Water supply device and method for detecting abnormality in the water supply device

Abstract

To provide a water feeder that can detect a malfunction in components of pump units without setting a threshold for malfunction determination according to the rotation speed of a motor, and a method for detecting a malfunction in the water feeder.SOLUTION: A water feeder controls a plurality of pump units so as to perform parallel running or alternate parallel running. A malfunction in the water feeder is determined on the basis of the output from a vibration detector when a motor is controlled to shift into a small-water-amount stop mode where the rotation speed of the motor is fixed or a forced starting mode in a time zone with a small amount of the used water.SELECTED DRAWING: Figure 9

Description

[Technical field]

[0001] The present invention relates to a water supply device and an abnormality detection method for a water supply device, and more particularly to a water supply device that detects an abnormality using a vibration sensor and an abnormality detection method for the water supply device. [Background technology]

[0002] Water supply devices are widely used to supply water for use in apartment buildings, buildings, factories, etc. As shown in Fig. 12, water supply device 100 has two pump units 101A and 101B and a control device (not shown) that controls the pump units, and each of pump units 101A and 101B is controlled by the control device to operate independently or simultaneously in parallel. Each pump unit 101A, 101B is composed of a pump 102A, 102B that generates lift, and a motor 103A, 103B that transmits rotational power to the pump 102A, 102B, and the rotation of the motor 103A, 103B is controlled according to the amount of water used in the apartment complex, etc., and the operation of the multiple pump units 101A, 101B is controlled independently or simultaneously. In this way, the water supply device 100 pumps up tap water supplied from a water pipe and supplies it to an elevated water tank, etc., of the apartment complex.

[0003] A suction pressure sensor 105 is connected to the upstream side of the pump unit 101A and pump unit 101B, and flow rate sensors 106A, 106B and a discharge pressure sensor 107 are connected to the downstream side, respectively, which detect the water pressure and flow rate on the suction side and discharge side of the pump unit 101A and pump unit 101B and output them to the control device. In addition, an accumulator tank 108 is connected to the discharge side of the pump unit 101A and pump unit 101B, which maintains the pressure on the discharge side at a predetermined pressure. Reference numeral 109 denotes a check valve.

[0004] By combining and operating two pump units 101A and 101B in parallel, it is possible to make the entire device more compact and improve energy conservation compared to operating one large pump device. For example, Patent Document 1 proposes a water supply device that achieves a wide range of pumping performance and energy conservation by switching the connection between the two pump units.

[0005] Meanwhile, the water supply system is composed of mechanical parts such as an impeller that generates the lifting force for pumping water, and a motor that rotates and drives the impeller. In order to prevent deterioration or damage to these mechanical components that may cause a decrease in water supply performance or operation stoppage, maintenance work such as inspection and replacement of the components is performed. A vibration sensor is attached to the water supply system, and the presence or absence of an abnormality in the water supply system is monitored by comparing the output of the vibration sensor with a threshold value for determining an abnormality, and the appropriate timing for part replacement or maintenance is determined. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] JP 2020-176537 A Summary of the Invention [Problem to be solved by the invention]

[0007] As described above, the presence or absence of an abnormality can be monitored by comparing the output of the vibration sensor with the threshold for abnormality determination. However, since the output of the vibration sensor changes significantly with the operating state of the pump unit, it may be difficult to set an appropriate threshold. Specifically, for example, when a vibration sensor is attached to a motor to monitor the vibration level in order to determine an abnormality in the motor, the vibration level varies significantly depending on the rotation speed of the motor. That is, when the amount of water used is small, the motor rotates at a low speed and the vibration level is small. On the other hand, when the amount of water used is large, the motor rotates at a high speed and the vibration level is large. In this way, the appropriate value of the threshold for abnormality determination is significantly different between when the motor rotates at a low speed and when the motor rotates at a high speed. Although it is possible to set multiple thresholds according to the rotation speed of the motor, it is necessary to perform test operation in advance, measure the vibration level for each rotation speed, and set the threshold, which increases the number of test steps.In addition, it is necessary to change and set the threshold for abnormality determination according to the rotation speed, which causes a problem of complicating the abnormality determination process.

[0008] Therefore, the present invention has been made in consideration of the above-mentioned problems, and its object is to provide a water supply device that can detect the occurrence of an abnormality using a threshold value for abnormality detection in a simpler manner. [Means for solving the problem]

[0009] The above-mentioned problem is solved by the water supply device of the present invention, which includes a pump unit having a pump and an electric motor for driving the pump, and a control circuit for controlling the electric motor of the pump unit to a variable rotation speed mode in which the rotation speed is variably controlled according to the amount of water used, and a fixed rotation speed mode in which the rotation speed of the electric motor of the pump unit is controlled to be constant regardless of the amount of water used. and controlling the operation of the pump unit in the variable rotation speed mode and the fixed rotation speed mode. a control unit for controlling the pump unit to rotate in the fixed rotation speed mode, a vibration detector disposed in the pump unit, and an abnormality determination unit for determining an abnormality in the pump unit based on an output of the vibration detector when the control unit controls the electric motor to the fixed rotation speed mode. The fixed rotation speed mode is an operating state in which the rotation speed of the motor is stabilized at a predetermined rotation speed when the amount of water used becomes equal to or less than a predetermined amount of water, and the abnormality determination unit determines an abnormality in the pump unit by comparing the output of the vibration detector with a threshold value that is preset for an operating state at the predetermined rotation speed and does not correspond to an operating state other than the predetermined operating state. This is solved by:

[0010] According to the above configuration, the abnormality determination unit determines an abnormality based on the output of the vibration detector when the motor is controlled to a fixed rotation speed mode in which the rotation speed of the motor is constant, and therefore the occurrence of an abnormality can be detected by comparing the output of the vibration detector with a threshold value in the fixed rotation speed mode. This eliminates the need to measure and set an abnormality determination threshold value for each rotation speed of the motor that changes according to the amount of water used, thereby suppressing an increase in the number of test steps required to set the threshold value. Furthermore, since there is no need to change and set a threshold value for abnormality determination for each rotation speed, the abnormality determination process is prevented from becoming complicated.

[0012] The water supply device of the present invention provides a pump unit having a pump and an electric motor for driving the pump, and a variable rotation speed mode for variably controlling the rotation speed of the electric motor of the pump unit in accordance with the amount of water used. a fixed rotation speed mode in which the rotation speed of the electric motor of the pump unit is controlled to a constant value regardless of the amount of water used; Controlled and controlling the operation of the pump unit in the variable rotation speed mode and the fixed rotation speed mode. a control unit, a vibration detector disposed in the pump unit, an abnormality determination unit that determines an abnormality in the pump unit based on an output of the vibration detector, and a discharge pressure sensor on the discharge side of the pump unit, wherein in the variable rotation speed mode, the control unit variably controls the rotation speed of the motor of the pump unit in accordance with an amount of water used so that the output of the discharge pressure sensor coincides with a preset target pressure value, The fixed rotation speed mode is An operating state in which the pump unit is forcibly started from a state in which the pump unit is stopped, and the rotation speed of the electric motor is stabilized at a predetermined rotation speed. and The abnormality determination unit resolves this problem by determining an abnormality in the pump unit by comparing the output of the vibration detector with a threshold value that is preset for an operating state at the specified rotational speed and does not correspond to any operating state other than that operating state.

[0013] It is also preferable that the pump unit is provided with a temperature detector, the abnormality determination unit determines a temperature abnormality of the pump unit based on an output of the temperature detector when the control unit controls the electric motor to the variable rotation speed mode, and the control unit controls to stop operation of the pump unit based on the result of the temperature abnormality determination. This makes it possible to monitor abnormal heat generation of the motor and control to stop operation of the pump unit when abnormal heat generation is detected.

[0014] It is also preferable that the vibration detector is disposed in the electric motor to detect vibrations of the electric motor, thereby making it possible to detect an abnormality in the electric motor, which is one of the mechanical components that constitute the water supply apparatus and has a high frequency of abnormalities.

[0015] It is also preferable that the vibration detector has a three-axis vibration sensor, and the abnormality determination unit determines an abnormality based on a composite signal obtained by combining the vibration signals output from each axis of the three-axis vibration sensor. This enables the abnormality determination unit to detect an abnormality by an abnormality determination process common to both horizontal and vertical water supply devices. In addition, since there is no need to precisely align the installation position and installation direction of the vibration detector, the workload associated with installing the vibration detector can be reduced.

[0016] The problem is also solved by a method for detecting an abnormality in a water supply device having a pump unit having a pump and an electric motor for driving the pump, a control unit for controlling the operation of the pump unit, a vibration detector disposed in the pump unit, and an abnormality determination unit for determining an abnormality in the pump unit, the method including the steps of: the control unit controlling the electric motor of the pump unit to a variable rotation speed mode in which the rotation speed is variably controlled according to the amount of water used; and the control unit controlling the electric motor of the pump unit to a fixed rotation speed mode in which the rotation speed is controlled to a constant value regardless of the amount of water used. The control unit controls operation of the pump unit in the variable rotation speed mode and the fixed rotation speed mode; The control unit controls the electric motor The above and a step in which the abnormality determination unit determines an abnormality in the pump unit based on an output of the vibration detector when the pump unit is controlled to a fixed rotation speed mode. The fixed rotation speed mode is a state in which the rotation speed of the motor is stabilized at a predetermined rotation speed when the amount of water used becomes equal to or less than a predetermined amount of water, and the step of determining an abnormality determines an abnormality in the pump unit by comparing the output of the vibration detector with a threshold value that is preset for an operating state at the predetermined rotation speed and does not correspond to an operating state other than the operating state. This is solved by:

[0017] According to the above configuration, the abnormality determination unit determines an abnormality based on the output of the vibration detector when the motor is controlled to a fixed rotation speed mode in which the rotation speed of the motor is constant, and therefore the occurrence of an abnormality can be detected by comparing the output of the vibration detector with a threshold value in the fixed rotation speed mode. This eliminates the need to measure and set an abnormality determination threshold value for each rotation speed of the motor that changes according to the amount of water used, thereby suppressing an increase in the number of test steps required to set the threshold value. Furthermore, since there is no need to change and set a threshold value for abnormality determination for each rotation speed, the abnormality determination process is prevented from becoming complicated. Effect of the Invention

[0018] According to the water supply device of the present invention, it is possible to detect abnormalities in components of the pump unit without setting a threshold value for abnormality judgment for each motor rotation speed, thereby suppressing an increase in testing labor and the complication of the abnormality judgment process. [Brief description of the drawings]

[0019] [Figure 1] 1 is a perspective view of a water supply device according to one embodiment of the present invention; [Diagram 2] FIG. [Diagram 3] FIG. 2 is a partial perspective side view of the pump unit. [Figure 4] FIG. [Diagram 5] FIG. 2 is a diagram showing functional blocks of the water supply device. [Figure 6] FIG. 11 is a diagram illustrating a method for controlling the pump unit. [Figure 7] FIG. 13 is a diagram showing the flow of alternating operation and alternating parallel operation of the water supply apparatus. [Figure 8] FIG. 4 is a diagram showing the relationship between the operating frequency of an inverter and a vibration level. [Figure 9] FIG. 4 is a diagram showing a flow of an abnormality determination process. [Figure 10] 13A and 13B are diagrams illustrating modified examples regarding the mounting position of the vibration sensor. [Figure 11] FIG. 11 is a diagram showing a flow of a temperature abnormality determination process. [Figure 12] FIG. 1 is a diagram showing a schematic configuration of a conventional water supply device. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0020] An embodiment of the present invention (hereinafter, this embodiment) will be described below with reference to Figs. 1 to 12. The water supply device 10 of this embodiment will be described as being used to supply water for daily life in an apartment building or building, or other general water supply systems. However, this is not limited to this, and it can also be used to supply water for simple water supply systems, agricultural water, and industrial water, for example. In the following description, we will assume that a direct connection method is adopted in which the water supply device 10 is directly connected to a water pipe and tap water supplied from the water pipe is directly pumped up; however, it can also be used in a water tank method in which tap water is first stored in a water tank and then pumped up from a water supply device connected to the water receiving tank. In addition, although the following description will use as an example a horizontal water supply device in which the main shaft of the motor (electric motor) is arranged horizontally, the present invention can also be applied to a vertical water supply device in which the main shaft of the motor is arranged vertically.

[0021] 1 and 2 are a perspective view and a plan view of a water supply device 10 in this embodiment. The water supply device 10 has a base 11, two pump units (a first pump unit 19A and a second pump unit 19B) installed side by side on the base 11, and a control panel 13 that houses a control device 12 (not shown) that controls the operation of the two pump units 19A and 19B. The two pump units 19A and 19B are controlled by the control device 12 to operate in parallel either alone or simultaneously. The two pump units 19A and 19B increase the pressure of tap water sucked from a suction pipe connected to the suction ports 28A and 28B, and merge the discharged water in a junction pipe 14 connected to the discharge sides of the two pump units 19A and 19B, and discharge the water from a junction discharge port 15.

[0022] Here, since the first pump unit 19A and the second pump unit 19B have the same configuration, in the following description, when there is no need to particularly distinguish between the first pump unit 19A and the second pump unit 19B, they will be simply described as "pump unit 19." The same is true for the motor 24 and the flow rate sensor 20, which are components of the pump unit 19 described later, and the inverter 21 (see FIG. 5) that supplies electric energy to the motor 24.

[0023] A flow rate sensor 20A is attached to the discharge side of the first pump unit 19A, and a flow rate sensor 20B is attached to the discharge side of the second pump unit 19B. A discharge pressure sensor 17 that detects the water pressure on the discharge sides of the two pump units 19A and 19B is attached to the junction pipe 14. A flow rate signal output by the flow rate sensor 20 and a pressure signal output by the discharge pressure sensor 17 are input to a control device 12 housed in a control panel 13. In addition, a pressure accumulator tank 18 is connected to the junction pipe 14 to maintain the water pressure in the junction pipe 14 at a predetermined pressure.

[0024] The control panel 13 houses a control device 12 for controlling the operation of the two pump units 19A, 19B (see FIG. 5). The control device 12 controls the operation of the pump units 19A, 19B based on output signals from the discharge pressure sensor 17 and the flow rate sensors 20A, 20B. The control device 12 can control the first pump unit 19A and the second pump unit 19B to operate independently or simultaneously in parallel, and controls the first pump unit 19A and the second pump unit 19B to operate alternately, as will be described in detail later.

[0025] In addition to the control device 12, the control panel 13 houses a first inverter 21A that supplies electric energy to the first pump unit 19A and a second inverter 21B that supplies electric energy to the second pump unit 19B (see FIG. 5). An operation panel 22 is provided on the side of the control panel 13, which receives input operations from an operator and outputs information regarding the operating state and abnormalities of the water supply device 10.

[0026] In this embodiment, the water supply device 10 has two pump units 19A and 19B, but in order to ensure the necessary pumping capacity, it may have three or more, for example, six pump units 19. In this case, the control device 12 housed inside the control panel 13 can control the six pump units 19 to operate individually or simultaneously in parallel.

[0027] 3 is a partial perspective side view of pump unit 19. Pump unit 19 has pump 23 that generates lift and motor (electric motor) 24 that transmits rotational power to pump 23. Motor 24 converts electric energy supplied from inverter 21 housed inside control panel 13 into rotational power, which rotates impeller 29 disposed inside pump 23. The rotational motion of impeller 29 applies centrifugal force to water sucked in from suction port 28. This centrifugal force becomes lift, and the sucked water is discharged from discharge port 30 in an increased pressure state. Discharge port 30 is connected to junction pipe 14 described above.

[0028] In FIG. 3, pump 23 has three stages of impellers 29 arranged in the direction of the rotation shaft inside casing 25. However, as long as the required pumping performance is obtained, one, two, or four or more stages may be arranged side by side. In addition, the pump 23 houses an impeller 29 inside the casing 25 with the casing cover 26 connected, and is connected to a motor bracket 35 by a connecting bolt 27 inserted into a connecting hole (not shown) formed in the casing cover 26.

[0029] 4 is a partial perspective side view of the motor 24. The motor 24 is covered by a motor housing 34, a motor bracket 35, and a protective cover 36, and a main shaft 31 supported by a first bearing 32 and a second bearing 33 is disposed inside the motor housing 34 so as to extend in the longitudinal direction of the motor 24. The first bearing 32 and the second bearing 33 are ball bearings whose outer rings are fixed to the motor bracket 35 and the protective cover 36, and whose inner rings rotatably support the main shaft 31. The main shaft 31 protrudes from a shaft hole formed in the motor bracket 35 so as to extend outside the motor bracket 35 , and transmits the rotational power generated by the motor 24 to the impeller 29 of the pump 23 . In this embodiment, the motor 24 is a permanent magnet synchronous motor (PM motor), but it is sufficient if the motor can transmit the necessary rotational power to the pump 23, and it may be, for example, an induction motor.

[0030] A vibration sensor 37 , which corresponds to a vibration detector, is fixed by screws to a position adjacent to the first bearing 32 on the surface of the motor bracket 35 to detect vibrations generated from the first bearing 32 . The reason why the vibration sensor 37 is attached at the position shown in FIG. 4 is that friction generated between the outer and inner rings of the first bearing 32 made of ball bearings causes deterioration and damage of the first bearing 32 together with the rotation of the main shaft 31. When such deterioration and damage accumulate, the first bearing 32 generates vibration together with the rotation of the main shaft 31. Furthermore, since a load generated together with the rotation of the impeller 29 connected to the main shaft 31 inside the pump 23 is applied to the first bearing 32 via the main shaft 31, this load also causes deterioration and damage of the first bearing 32. Even when such deterioration and damage accumulate, the first bearing 32 generates vibration together with the rotation of the main shaft 31. Therefore, the vibration can be accurately measured by attaching the vibration sensor 37 to a position adjacent to the first bearing 32. As will be described later, the water supply device 10 of this embodiment performs an abnormality determination based on the output of the vibration sensor 37.

[0031] The vibration sensor 37 may be a piezoelectric acceleration detector, but may be, for example, a capacitance type vibration sensor as long as it can obtain the desired vibration detection performance. In this embodiment, the vibration sensor 37 is fixed to the motor bracket 35 by screwing, but as long as it can accurately measure the vibration generated from the first bearing 32, it may be fixed using a fixing member other than a screw or by magnetic force.

[0032] It is desirable to attach the vibration sensor 37 to the motor bracket 35 in a position and orientation that allows it to detect vibrations in three axial directions (the vertical direction, the direction of the main shaft 31 of the motor 24, and the horizontal direction perpendicular to the vertical direction and the direction of the main shaft 31). This allows the presence or absence of an abnormality to be determined based on the amplitude level of the vibration signal in each of the three axial directions in an abnormality determination process executed by the abnormality determination unit 41, which will be described later.

[0033] Furthermore, the presence or absence of an abnormality may be determined using a composite signal obtained by combining the vibration signals for each axis of the vibration sensor 37 (three-axis vibration sensor). The composite signal V can be calculated by the following formula. Here, V1, V2, and V3 are the amplitude levels of the vibration signals for each axis output by the vibration sensor 37. By using such a composite signal, it is no longer necessary to accurately align the vibration sensor 37 with respect to the vertical direction, the direction of the main shaft 31, and the horizontal direction perpendicular to the vertical direction and the direction of the main shaft, thereby reducing the workload involved in installing the vibration sensor 37.

[0034]

number

[0035] Fig. 5 shows functional blocks of the water supply device 10. As shown in Fig. 5, the control panel 13 accommodates the control device 12, the first inverter 21A, and the second inverter 21B therein, and controls the operation of the first pump unit 19A and the second pump unit 19B by outputting control signals from the control device 12 to the first inverter 21A and the second inverter 21B. An operation panel 22 is provided on the side of the control panel 13, which accepts operation inputs to the control device 12 and outputs information relating to the operating state and abnormalities of the water supply device 10. Information relating to the operating state and abnormalities of the water supply device 10 may be output to a communication device 38 which can communicate with the outside world by wire or wirelessly.

[0036] The control device 12 includes a pump unit control section 39, a sensor signal acquisition section 40, an abnormality determination section 41, and a timing section . The sensor signal acquisition unit 40 acquires output signals from the discharge pressure sensor 17, the flow rate sensor 20, and the vibration sensor 37, and outputs the pressure signal, the flow rate signal, and the vibration signal to the pump unit control unit 39 and the abnormality determination unit 41. The sensor signal acquisition unit 40 has an A / D converter, an LPF (low pass filter), and a BPF (band pass filter), and can convert analog signals to digital signals as necessary, remove noise in unnecessary frequency bands, and output signals having desired frequency components.

[0037] As described below, the pump unit control unit 39 outputs control signals for the first pump unit 19A and the second pump unit 19B via the first inverter 21A and the second inverter 21B based on the signal acquired by the sensor signal acquisition unit 40. The first inverter 21A and the second inverter 21B are connected to a single-phase or three-phase AC commercial power source, and perform frequency conversion of the AC signal based on a control signal from the pump unit control unit 39, thereby controlling the operation of the first pump unit 19A and the second pump unit 19B.

[0038] The abnormality determination unit 41 determines the presence or absence of an abnormality based on the amplitude level of the vibration signal of the vibration sensor 37 acquired by the sensor signal acquisition unit 40. The method of abnormality determination by the abnormality determination unit 41 will be described later. The timer unit 42 uses a crystal oscillator and measures the operation time of the low water volume stop mode, which will be described later, and the start timing of the forced start mode. The timer unit 42 only needs to be able to obtain the necessary accuracy for timing, and may use a ceramic oscillator.

[0039] The control device 12 is equipped with a CPU, non-volatile memory, and volatile memory (not shown), and the non-volatile memory stores programs for implementing the functions of the pump unit control unit 39 and the abnormality determination unit 41. The CPU loads these programs from the non-volatile memory to the volatile memory and executes them. As a result, the control device 12 functions as the pump unit control unit 39 and the abnormality determination unit 41.

[0040] FIG. 6 is a diagram showing a method of controlling the pump unit 19 by the pump unit control unit 39. When the water supply device 10 starts, the pump unit control unit 39 controls the output of the discharge pressure sensor 17 acquired via the sensor signal acquisition unit 40 so that it coincides with a preset target pressure value. Specifically, the pump unit control unit 39 performs a PID calculation based on the preset target pressure value and the output of the discharge pressure sensor 17 acquired by the sensor signal acquisition unit 40, and calculates the operation frequency of the inverter 21. The rotation speed of the motor 24 is controlled by the operation frequency of the inverter 21. The water sucked from the suction port 28 is pressurized by transmitting the rotational power of the motor 24 to the impeller 29 of the pump 23. At this time, the output of the discharge pressure sensor 17 is fed back and used again as an input signal for the PID calculation. The pump unit control unit 39 controls the operation of the pump unit 19 by the above control method. Either the constant discharge pressure control method or the constant estimated end pressure control method may be adopted.

[0041] For example, in an environment where the amount of water used varies depending on the time of day, such as an apartment building or a building, the pump unit control unit 39 must constantly variably control the rotation speed of the motor 24 according to the amount of water used in order to keep the output of the discharge pressure sensor 17 constant. That is, the pump unit control unit 39 starts the operation of the pump unit 19 and controls the operation of the pump unit 19 in the variable rotation speed mode. The pump unit control unit 39 controls the operation of the pump unit 19 in the variable rotation speed mode except in the low water volume stop mode and forced start mode, which will be described later.

[0042] Next, the alternating operation and the alternating parallel operation of the first pump unit 19A and the second pump unit 19B will be described. The water supply device 10 in this embodiment has two pump units 19A and 19B, and supplies the water to be used by controlling the operation of these units. Specifically, when the amount of water used can be supplied by one pump unit 19, the amount of water used is supplied by alternately operating either the first pump unit 19A or the second pump unit 19B. This is called alternating operation. On the other hand, when the amount of water used exceeds the amount of water that can be supplied by one pump unit 19, the two pump units 19A and 19B are operated in parallel at the same time, and the order of starting and stopping the operation is alternated to supply the amount of water used. This is called alternating parallel operation.

[0043] Fig. 7 shows the flow of alternating operation and alternating parallel operation executed by the pump unit control unit 39. Specifically, steps S10 to S17 in Fig. 7 show the flow of alternating operation, and steps S10 to S12 and steps S18 to S23 show the flow of alternating parallel operation. As an example of operation control, the pump unit control section 39 performs constant discharge pressure control by setting a predetermined set pressure P1 as the target pressure H. Alternatively, as another example of normal operation control, the pump unit control section 39 performs constant estimated terminal pressure control by setting a fluctuation value between the estimated terminal pressure P2 and a predetermined set pressure P1 as the target pressure H.

[0044] When water is used by residents of an apartment building or the like, the pressure value P output by the discharge pressure sensor 17 decreases. Therefore, in step S10, the pump unit control unit 39 determines whether the pressure value P output by the discharge pressure sensor 17 has fallen below a preset start pressure P3. If the pressure value P of the discharge pressure sensor 17 is not below the start pressure P3 (step S10; No), the pump unit control unit 39 waits until the pressure value P falls below the start pressure P3.

[0045] On the other hand, if the pressure falls below the starting pressure P3 (step S10; Yes), the pump unit control section 39 outputs a control signal to the first inverter 21A to start the rotation of the motor 24A of the first pump unit 19A (step S11). Here, the first pump unit 19A is described as starting to operate before the second pump unit 19B, but the second pump unit 19B may start to operate before the first pump unit 19A. As described above, the pump unit control section 39 outputs a control signal to the first inverter 21A so that the pressure value P of the discharge pressure sensor 17 coincides with the target pressure H that is determined in advance.

[0046] Then, the pump unit control unit 39 determines whether the amount of water usage has decreased to the stop flow rate Q1 or less (step S12). If the amount of water usage is below the stop flow rate Q1 (step S12; Yes), the pump unit control unit 39 controls the first pump unit 19A to stop operation in step S13.

[0047] Here, the pump unit control section 39 controls the first pump unit 19A to transition to a small water volume stop mode immediately before stopping the operation of the first pump unit 19A. The small water volume stop mode is an operation state immediately before the rotation of the motor 24 is completely stopped, and is an operation in which the operation of the pump unit 19 is stopped after continuing the operation for a predetermined time (e.g., 2 seconds) in a state in which the rotation speed of the motor 24 is stabilized at a predetermined rotation speed regardless of the amount of water used. In order to keep the rotation speed of the motor 24 constant during the small water volume stop mode, the first pump unit 19A controls the operation frequency of the first inverter 21A to a constant frequency (e.g., the minimum frequency). Here, the constant rotation speed and the constant frequency do not need to be strictly constant rotation speeds (frequency), but include a state in which a stable value is maintained within a certain fluctuation range regardless of the amount of water used. As will be described later, when the pump unit control unit 39 transitions the first pump unit 19A to the low water volume stop mode, the abnormality determination unit 41 determines whether or not there is an abnormality in the pump unit 19A based on the output of the vibration sensor 37. The low water volume stop mode is an example of a fixed rotation speed mode.

[0048] Then, the pump unit control unit 39 judges whether or not the pressure value P output by the discharge pressure sensor 17 has fallen below the start pressure P3 again (step S14). If the pressure value P of the discharge pressure sensor 17 has not fallen below the start pressure P3 (step S14; No), the pump unit control unit 39 waits until the pressure value P falls below the start pressure P3. On the other hand, if the pressure falls below the starting pressure P3 (step S14; Yes), the pump unit control section 39 outputs a control signal to the second inverter 21B to start the rotation of the motor 24B of the second pump unit 19B (step S15). In this way, each time the amount of water used decreases and the pump unit 19 is stopped, the pump unit 19 to be started next is operated while being switched between the first pump unit 19A and the second pump unit 19B. This is called alternating operation.

[0049] Then, the pump unit control unit 39 judges whether the amount of water usage has decreased again and become equal to or less than the stop flow rate Q1 (step S16). If it is not below the stop flow rate Q1 (step S16; No), the operation is continued as is. On the other hand, if the amount of water usage falls below the stop flow rate Q1 (step S16; Yes), the pump unit control unit 39 controls the second pump unit 19B to stop operation (step S17). Specifically, the pump unit control unit 39 operates the second pump unit 19B in the small water volume stop mode and then stops the operation of the second pump unit 19B.

[0050] If the amount of water supply increases during isolated operation and it is determined that the pressure value P is equal to or lower than the target pressure H, the process proceeds to step S18. The pump unit control section 39 increases the operating frequency of the first inverter 21A so as to change the rotation speed of the first motor 24A of the first pump unit 19A to a high speed rotation.

[0051] Next, a case will be described in which the amount of water used further increases and it becomes impossible to control the pressure value P to coincide with the target pressure H by a single pump unit 19. At this time, the pressure value P of the discharge pressure sensor 17 becomes lower than the target pressure H. Therefore, in step S18, the pump unit control section 39 determines whether or not the pressure value P is lower than the target pressure H. If the pressure value P is not lower than the target pressure H (step S18; No), the operation is continued as is.

[0052] On the other hand, when the pressure value P falls below the target pressure H (step S18; Yes), the pump unit control section 39 controls the second pump unit 19B, which is in a stopped state, to start operation (step S19). As a result, the two pump units 19A and 19B are brought into a state of operating in parallel.

[0053] Thereafter, the pump unit control section 39 judges whether the pressure value P exceeds the target pressure H and the motors 24 of the pump units 19 operating in parallel are stable at a predetermined rotation speed, i.e., whether the inverters 21 are stable at a predetermined operating frequency (e.g., the minimum frequency) (step S20). If the motors 24 are not stable at the predetermined rotation speed (step S20; No), the parallel operation is continued as it is. On the other hand, if the rotation speed is stable at a predetermined speed (step S20; Yes), the amount of water used can be supplied by one pump unit 19, so the pump unit control section 39 controls the first pump unit 19A to stop operation (step S21). At this time, the first pump unit 19A, which had been in operation until then, goes into a suspended state, while the second pump unit 19B continues to operate.

[0054] Next, the pump unit control section 39 judges whether the amount of water usage has further decreased to the stop flow rate Q1 or less (step S22). If the amount of water usage has not decreased below the stop flow rate Q1 (step S22; No), the operation is continued as it is. On the other hand, if the flow rate falls below the stop flow rate Q1 (step S22; Yes), the pump unit control section 39 controls the second pump unit 19B to transition to the small water volume stop mode and then stop operation (step S23).

[0055] As described above, the pump unit 19 that started operation first stops operation first and goes into a suspended state when the amount of water used decreases after parallel operation. The pump unit 19 that started operation later continues operation after the pump unit 19 that started operation earlier stops operation, and then stops. In this way, the two pump units 19A and 19B are operated in parallel at the same time, and water is supplied by alternating the order of starting and stopping operation. This is called alternating parallel operation.

[0056] As described above, the pump unit control section 39 variably controls the rotation speed of the motor 24 according to the amount of water used, and controls the two pump units 19A, 19B to perform alternating operation and alternating parallel operation. When the amount of water used falls below the stop flow rate Q1, just before stopping the operation of the pump unit 19, it controls the mode to transition to a low water volume stop mode in which the motor 24 rotates at a constant rotation speed regardless of the amount of water used.

[0057] As described later, the abnormality determination section 41 determines whether or not there is an abnormality in the pump unit 19 based on the output of the vibration sensor 37 when the pump unit control section 39 transitions the motor 24 to the small water volume stop mode. This makes it possible to detect an abnormality without affecting the operation of the water supply device 10.

[0058] Next, the abnormality determination process performed by the abnormality determination unit 41 will be described. 8 is a diagram showing the relationship between the operating frequency of the inverter 21 and the amplitude level of the vibration signal output by the vibration sensor 37 for cases where there is no abnormality and where there is an abnormality in the first bearing 32. The abnormality determination unit 41 according to this embodiment determines that there is an abnormality in the first bearing 32 when the amplitude level exceeds a preset threshold value. However, the amplitude level of the vibration signal varies depending on the operation frequency of the inverter 21. For example, as shown in Fig. 8, the amplitude level of the vibration signal output by the vibration sensor 37 is significantly different when the inverter 21 is operated at the first operation frequency F1 and when it is operated at the second operation frequency F2. As shown in Fig. 8, the amplitude level of the vibration signal is higher when there is no abnormality when the inverter 21 is operated at the second operation frequency F2 than when there is an abnormality when the inverter 21 is operated at the first operation frequency F1. Therefore, it is not possible to set a common threshold value when the inverter 21 is operated at the first operation frequency F1 and when it is operated at the second operation frequency F2.

[0059] Here, it is also conceivable to set a plurality of thresholds (for example, th1 and th2) for each operating frequency of the inverter 21. In that case, however, it is necessary to carry out a test run in advance to set the threshold for each operating frequency, and to obtain the output of the vibration sensor 37 while changing the operating frequency. Furthermore, when the water supply device 10 is used in an environment where the amount of water used varies greatly, such as an apartment building, the operating frequency of the inverter 21 frequently changes depending on the amount of water used, and it becomes necessary to change the threshold each time, which complicates the abnormality determination process described below.

[0060] Therefore, the abnormality determination unit 41 of this embodiment determines an abnormality using the amplitude level of the vibration signal from the vibration sensor 37 when the motor 24 of the pump unit 19 is transitioned to the low water volume stop mode and the rotational speed of the motor 24 is fixed at a constant rotational speed regardless of the amount of water used. This makes it possible to detect an abnormality in the first bearing 32 without setting a plurality of threshold values ​​for each operating frequency.

[0061] FIG. 9 shows the flow of the abnormality determination process executed by the abnormality determination unit 41. First, the abnormality determination unit 41 determines whether the motor 24 of the first pump unit 19A or the second pump unit 19B has been controlled to the small water volume stop mode (step S30). When the pump unit control unit 39 controls the motor 24A of the first pump unit 19A to the small water volume stop mode, the pump unit control unit 39 stores a small water volume stop flag for the first pump unit 19A in the volatile memory of the control device 12. Then, when the first pump unit 19A completely stops, the pump unit control unit 39 performs a process of erasing the small water volume stop flag from the volatile memory. Therefore, the abnormality determination unit 41 can determine that the first pump unit 19A has been controlled to the small water volume stop mode by checking whether the small water volume stop flag is stored in the volatile memory. The same applies to the second pump unit 19B.

[0062] If it is determined that the mode has not been controlled to the small water volume stop mode (step S30; No), the abnormality determination unit 41 waits until the mode is controlled to the small water volume stop mode. On the other hand, if it is determined that the motor 24 has been controlled to the small water volume stop mode (step S30; Yes), the abnormality determination unit 41 acquires the vibration signal of the vibration sensor 37 via the sensor signal acquisition unit 40 (step S31). Specifically, the abnormality determination unit 41 acquires the vibration signal for a predetermined measurement time during the period in which the motor 24 is controlled to the small water volume stop mode and rotates at a constant rotation speed.

[0063] Next, the abnormality determination unit 41 calculates a composite signal of the acquired vibration signals (step S32). That is, the composite signal is calculated from the three vibration signals corresponding to the three axes using the above-mentioned formula 1. This makes it possible to execute a common abnormality determination process not only for the horizontal water supply apparatus described in this embodiment, but also for the vertical water supply apparatus. Also, since there is no need to precisely align the mounting position and mounting direction of the vibration sensor 37 with respect to the motor bracket 35, the workload associated with fixing the vibration sensor 37 can be reduced.

[0064] Next, the abnormality determination unit 41 determines the peak level and the effective value (step S33). In this embodiment, the peak level is the largest signal level of all the composite signals during the measurement time. In addition, in this embodiment, the effective value is the average value of the squared values ​​of the composite signal. In calculating the average value, the average value of all the squared values ​​during the measurement time may be calculated, or the target interval for calculating the average value may be shifted sequentially and the average value obtained for each target interval, i.e., the moving average value, may be calculated.

[0065] Next, the abnormality determination unit 41 determines the presence or absence of an abnormality in step S34. Specifically, it determines whether the peak level is greater than a first threshold value TH1, and determines whether the effective value is greater than a second threshold value TH2. Here, the first threshold value TH1 is a threshold value that is preset for determining an abnormality in the first bearing 32 based on the peak level. Also, the second threshold value TH2 is a threshold value that is preset for determining an abnormality in the first bearing 32 based on the effective value. In this embodiment, the abnormality determination unit 41 determines that an abnormality exists when the peak level is determined to be greater than the first threshold value TH1 and the effective value is determined to be greater than the second threshold value TH2. In this manner, by comparing both the peak level and the effective value with the first threshold value TH1 and the second threshold value TH2, respectively, the reliability of abnormality detection can be improved. Here, if the peak level is not determined to be greater than the first threshold value TH1, the effective value may not be calculated. Conversely, if the effective value is not determined to be greater than the second threshold value TH2, the peak level may not be calculated.

[0066] If it is determined that there is an abnormality (step S34; Yes), the abnormality determination unit 41 outputs a warning signal to the operation panel 22 (step S35), and a warning is displayed on the operation panel 22. In addition, the abnormality determination unit 41 outputs a warning signal to the communication device 38 that can communicate with an external monitoring device by wired or wireless communication, and ends the abnormality determination process. On the other hand, if it is determined that no abnormality exists (step S34; No), the abnormality determination unit 41 ends the abnormality determination process without outputting a warning.

[0067] In this way, the abnormality determination unit 41 in this embodiment determines whether or not an abnormality exists using a threshold value that is preset for the low water volume stop mode, so there is no need to switch between multiple threshold values ​​for each rotation speed of the motor 24, and the complexity of the abnormality detection process can be suppressed. In addition, the abnormality determination unit 41 performs abnormality determination in the low water volume stop mode, which is entered when the amount of water used decreases in an apartment building or the like and is about to be switched to just before the pump unit 19 stops operating, so that it is possible to determine whether or not an abnormality exists without affecting the water supply performance of the water supply device 10.

[0068] The method of determining an abnormality is not limited to the above-mentioned method. For example, F(E) calculated by the following polynomial may be used as a determination value, and the determination value may be compared with a threshold value to determine an abnormality. Here, E is an effective value, and a0, a1, a2, and a3 are each predetermined coefficients. By comparing the determination value calculated by the following polynomial with the threshold value, rather than comparing the effective value with the threshold value, the accuracy of determining an abnormality can be improved.

[0069]

number

[0070] 10 shows a modified example regarding the mounting position of the vibration sensor 37. In the above-described embodiment, the vibration sensor 37 is described as being mounted on the surface of the motor bracket 35 at a position adjacent to the first bearing 32. In contrast, the vibration sensors 37a, 37b, and 37c according to this modified example are mounted at positions different from this, and measure vibrations generated by a cause different from that of the first bearing 32.

[0071] The vibration sensor 37a is attached to a position adjacent to the second bearing 33 on the surface of the protective cover 36, and measures the vibration generated by the second bearing 33. The second bearing 33 is a ball bearing like the first bearing 32, and friction generated between the outer ring and the inner ring causes deterioration and damage to the second bearing 33. When such deterioration and damage accumulates, the vibration generated from the second bearing 33 increases as the main shaft 31 rotates. This is measured by the vibration sensor 37a. Then, the abnormality determination unit 41 executes the abnormality determination process described above to determine an abnormality in the second bearing 33. Here, as the threshold value for determining an abnormality in the second bearing 33, a threshold value different from the threshold value for determining an abnormality in the first bearing 32 may be set.

[0072] Vibration sensor 37b is attached to the annular surface of disk-shaped suction port 28 of pump 23. Vibration sensor 37c is attached to a suction pipe connected to suction port 28. Vibration sensors 37b and 37c measure vibrations caused by cavitation occurring near suction port 28. To explain cavitation, when pump unit 19 is in operation, the water pressure near suction port 28 is reduced by impeller 29 rotating at high speed. The reduced water pressure lowers the boiling point, which can cause the suctioned water to vaporize and generate bubbles. This phenomenon of vaporizing suctioned water is called cavitation. When cavitation occurs, it generates vibrations and noise from around suction port 28, reduces the pumping performance of pump 23, and causes damage to pump 23 and the suction piping.

[0073] Therefore, by providing the vibration sensors 37b, 37c to the suction port 28 and the suction piping, the occurrence of cavitation can be reliably detected. As described above, cavitation occurs when the motor 24 rotates at high speed and the water pressure near the suction port 28 drops, but does not occur in the low water volume stop mode.

[0074] In this way, by attaching a plurality of vibration sensors 37, 37a, 37b, 37c to the water supply apparatus 10, it is possible to detect abnormalities in the components of the water supply apparatus 10 and the occurrence of cavitation. Here, the number and positions of vibration sensors 37 to be attached are not limited to those mentioned above. For example, in addition to vibration sensors 37, 37a, 37b, and 37c, vibration sensor 37d may be disposed on the upper surface of base 11 (see FIG. 1) of water supply device 10 to measure the vibration of base 11 in order to identify the cause of vibration in water supply device 10. By identifying the cause of vibration, such as an abnormality in first bearing 32 or second bearing 33, which are components of water supply device 10 described above, or the occurrence of cavitation, it becomes possible to take prompt action, such as replacing parts.

[0075] 11 shows a modified example of the abnormality determination unit 41, and illustrates a temperature abnormality determination process executed by the abnormality determination unit 41. In the above-described embodiment, the abnormality determination unit 41 has been described as detecting an abnormality in the first bearing 32 based on the output of the vibration sensor 37. In contrast, the abnormality determination unit 41 according to this modified example detects abnormality in the first bearing 32 based on the output of the vibration sensor 37, and in addition detects abnormal heat generation (temperature abnormality) in the motor 24 based on the output of the temperature sensor 43 corresponding to a temperature detector, and determines whether or not the operation of the pump unit 19 needs to be stopped. In this way, the abnormality determination unit 41 detects an abnormality occurring in the first bearing 32 and detects abnormal heat generation in the motor 24, and stops the operation of the pump unit 19 when abnormal heat generation is detected.

[0076] Here, the temperature sensor 43 is attached on the surface of the motor bracket 35 at a position adjacent to the first bearing 32 and the vibration sensor 37. The temperature sensor 43 can monitor heat generation from the armature winding (stator) housed inside the motor housing 34. In this modification, if abnormal heat generation is detected, the pump unit control unit 39 stops the operation of the pump unit 19.

[0077] 11, in step S40, the abnormality determination unit 41 acquires the temperature signal output by the temperature sensor 43 via the sensor signal acquisition unit 40. Next, the abnormality determination unit 41 determines whether or not abnormal heat is occurring (step S41). That is, it determines whether or not the temperature signal is greater than a third threshold value TH3. The third threshold value TH3 is a temperature that can be set in advance based on the operable temperature of the motor 24. The operable temperature of the motor 24 is an allowable operating temperature of the motor 24 that is determined based on the temperature at which the insulation of the armature winding can be ensured, etc.

[0078] If it is determined that there is an abnormality (step S41; Yes), the abnormality determination unit 41 outputs a warning signal to the operation panel 22 and the communication device 38 (step S42). Next, the abnormality determination unit 41 outputs a signal to stop the operation of the pump unit 19 to the pump unit control unit 39 (step S43), and ends the abnormality determination process. On the other hand, if it is determined that no abnormality exists (step S41; No), the abnormality determination process ends without outputting a warning signal and an operation stop signal.

[0079] According to this modification, it is possible to monitor abnormal heat generation of the motor 24 and control the operation of the pump unit 19 to stop based on the result of the abnormal heat generation. If an abnormality in the first bearing 32 is detected, a warning is output and the operation of the pump unit 19 is continued, and the operation of the pump unit 19 is controlled to stop only when an abnormal temperature of the motor 24 is detected. In other words, it is possible to appropriately control the operation of the pump unit 19 depending on the cause of the abnormality. Although the temperature abnormality determination process has been described as being executed regardless of the operation mode of the motor 24, it is also possible to detect a temperature abnormality only in the variable rotation speed mode described above.

[0080] Also, the temperature abnormality determination process may be executed immediately before the operation of the pump unit 19 is started, and if a temperature abnormality is detected, the operation of the pump unit 19 may not be started. That is, the abnormality determination section 41 performs the temperature abnormality determination process immediately before the pump unit control section 39 controls the start of operation of the pump unit 19, and if it is determined that there is a temperature abnormality, it outputs an operation stop signal for the pump unit 19 to the pump unit control section 39. As a result, the pump unit 19 does not start operating.

[0081] Next, a second modified example of the abnormality determination process executed by the abnormality determination unit 41 will be described. In the above embodiment, the abnormality determination unit 41 has been described as detecting an abnormality based on the output of the vibration sensor 37 when the motor 24 is controlled to the low water volume stop mode. In contrast, in this modified example, when the two pump units 19A and 19B are stopped during a time period when water usage is low in an apartment building or the like (for example, from 2:00 a.m. to 5:00 a.m.), the pump unit control unit 39 detects an abnormality in a forced start mode in which the two pump units 19A and 19B are forced to start in sequence. The forced start mode is an operation mode in which the motor 24 of the pump unit 19 is rotated at a constant rotation speed for a predetermined short period of time from a state in which the motor 24 is stopped. The forced start mode is an example of a fixed rotation speed mode.

[0082] The pump unit control section 39 determines whether or not the timing to transition to the forced start mode has arrived, based on the time information output by the timer section 42 and the operating states of the two pump units 19A, 19B. Then, when it is time to switch to the forced start mode (for example, 2:00 a.m.) and it is determined that both pump units 19A and 19B are in a stopped state, the first pump unit 19A is forced to start, and the motor 24 is rotated at a constant rotation speed. After a predetermined time has elapsed, the first pump unit 19A is controlled to stop, and the same control is performed on the second pump unit 19B.

[0083] The abnormality determination unit 41 determines whether or not the motor 24 has been controlled to the forced start mode by the pump unit control unit 39. To explain this determination method, when the pump unit control unit 39 controls the motor 24 to the forced start mode, it stores a forced start flag in the volatile memory of the control device 12. Then, when the forced start mode of the motor 24 ends and the motor 24 stops, a process is performed to erase the forced start flag from the volatile memory. Therefore, the abnormality determination unit 41 can determine whether or not the pump unit 19 has been controlled to the forced start mode by checking whether or not the forced start flag is stored in the volatile memory.

[0084] When the pump unit 19 is controlled to the forced start mode, the abnormality judgment unit 41 acquires the vibration signal output by the vibration sensor 37 via the sensor signal acquisition unit 40, and judges whether or not an abnormality exists by the abnormality judgment processing of the above-mentioned embodiment. This makes it possible to detect an abnormality during times when water usage is low and when the pump unit 19 is stopped, making it possible to detect an abnormality without affecting water supply performance.

[0085] If water is used by residents of an apartment building or the like during the forced start mode and the pressure value P output by the discharge pressure sensor 17 drops below the start pressure P3, the forced start mode is immediately terminated. The pump unit control section 39 then starts controlling the operation of the pump unit 19 in the variable rotation speed mode. After operation in the variable rotation speed mode is terminated, the forced start mode can be switched back to and an abnormality can be detected.

[0086] Although the embodiment and some modified examples of the present invention have been described, these are merely examples for facilitating understanding of the present invention and are not intended to limit the present invention. In other words, the present invention can be modified or improved without departing from the spirit of the present invention, and of course, the present invention includes equivalents thereof. [Explanation of symbols]

[0087] 10 Water supply device 11 Foundation 12 Control device 13 Control Panel 14 Confluence pipe 15 Merging outlet 17 Discharge pressure sensor 18 Accumulator tank 19 Pump unit 19A First pump unit 19B Second pump unit 20 Flow Sensor 20A First Flow Sensor 20B Second flow sensor 21 Inverter 21A First Inverter 21B Second inverter 22 Operation Panel 23 Pump 24 Motor 24A First Motor 24B Second Motor 25 Casing 26 Casing cover 27 Connecting bolt 28 Intake port 29 Impeller 30 outlet 31 Main shaft 32 First Bearing 33 Second Bearing 34 Motor housing 35 Motor bracket 36 Protective cover 37 Vibration Sensor 38 Communication Equipment 39 Pump unit control section 40 Sensor signal acquisition unit 41 Abnormality determination section 42 Timing section 43 Temperature Sensor 100 Water supply equipment 101A First pump unit 101B Second pump unit 102A First Pump 102B Second Pump 103A First Motor 103B Second motor 105 Suction pressure sensor 106A, 106B Flow Sensor 107 Discharge pressure sensor 108 Accumulator Tank 109 Check valve

Claims

1. A pump unit having a pump and an electric motor for driving the pump; a control unit that controls the electric motor of the pump unit between a variable rotation speed mode in which the rotation speed is variably controlled according to the amount of water used, and a fixed rotation speed mode in which the rotation speed of the electric motor of the pump unit is controlled to be constant regardless of the amount of water used, and controls the operation of the pump unit in the variable rotation speed mode and the fixed rotation speed mode; A vibration detector disposed in the pump unit; an abnormality determination unit that determines an abnormality of the pump unit based on an output of the vibration detector when the control unit controls the electric motor to the fixed rotation speed mode, The fixed rotation speed mode is an operating state in which the rotation speed of the motor is stabilized at a predetermined rotation speed when the amount of water used becomes equal to or less than a predetermined amount of water, The water supply device is characterized in that the abnormality determination unit determines an abnormality in the pump unit by comparing the output of the vibration detector with a threshold value that is preset for an operating state at the specified rotational speed and does not correspond to any operating state other than that operating state.

2. A pump unit having a pump and an electric motor for driving the pump; a control unit that controls the electric motor of the pump unit between a variable rotation speed mode in which the rotation speed is variably controlled according to the amount of water used, and a fixed rotation speed mode in which the rotation speed of the electric motor of the pump unit is controlled to be constant regardless of the amount of water used, and controls the operation of the pump unit in the variable rotation speed mode and the fixed rotation speed mode; A vibration detector disposed in the pump unit; an abnormality determination unit that determines an abnormality in the pump unit based on an output of the vibration detector; a discharge pressure sensor on the discharge side of the pump unit; The control unit is In the variable rotation speed mode, the rotation speed of the motor of the pump unit is variably controlled in accordance with the amount of water used so that the output of the discharge pressure sensor coincides with a preset target pressure value; the fixed rotation speed mode is an operating state in which the pump unit is forced to start from a state in which the operation of the pump unit is stopped, and the rotation speed of the electric motor is stabilized at a predetermined rotation speed; The water supply device is characterized in that the abnormality determination unit determines an abnormality in the pump unit by comparing the output of the vibration detector with a threshold value that is preset for an operating state at the specified rotational speed and does not correspond to any operating state other than that operating state.

3. A temperature detector is provided in the pump unit, the abnormality determination unit determines a temperature abnormality of the pump unit based on an output of the temperature detector when the control unit controls the electric motor to the variable rotation speed mode, 3. The water supply apparatus according to claim 1, wherein the control unit controls the pump unit to stop operation based on the result of the determination of the temperature abnormality.

4. 4. The water supply apparatus according to claim 1, wherein the vibration detector is disposed on the electric motor and detects vibration of the electric motor.

5. The vibration detector is a three-axis vibration sensor, The water supply device according to any one of claims 1 to 4, characterized in that the abnormality determination unit determines an abnormality based on a composite signal obtained by combining the vibration signals output for each axis of the three-axis vibration sensor.

6. A pump unit having a pump and an electric motor for driving the pump; A control unit for controlling an operation of the pump unit; A vibration detector disposed in the pump unit; An abnormality detection method for a water supply apparatus having an abnormality determination unit that determines an abnormality in the pump unit, The control unit controls the electric motor of the pump unit to a variable rotation speed mode in which the rotation speed is variably controlled according to an amount of water used; The control unit controls the electric motor of the pump unit to a fixed rotation speed mode in which the rotation speed is controlled to be constant regardless of an amount of water used; The control unit controls operation of the pump unit in the variable rotation speed mode and the fixed rotation speed mode; and a step in which the abnormality determination unit determines an abnormality in the pump unit based on an output of the vibration detector when the control unit controls the electric motor to the fixed rotation speed mode, The fixed rotation speed mode is a state in which the rotation speed of the motor is stabilized at a predetermined rotation speed when the amount of water used becomes equal to or less than a predetermined amount of water, A method for detecting an abnormality in a water supply system, characterized in that the step of determining an abnormality determines an abnormality in the pump unit by comparing the output of the vibration detector with a threshold value that is preset for an operating state at the specified rotational speed and does not correspond to any operating state other than that operating state.

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