Compressor and monitoring method of compressor

Abstract

A compressor is provided with: a compressor main body (1) housed in a housing (4); a motor (2) for driving the compressor body (1); an electromagnetic switch (6) for switching a circuit for supplying current to the motor (2); the temperature sensor (9) is arranged in the shell (4); and a control device (7) that counts the switching of the electromagnetic switch (6), stores the cumulative switching count, and controls the electromagnetic switch (6), the control device (7) corrects the count value of the switching of the electromagnetic switch (6) on the basis of the temperature detected by the temperature sensor (9), and outputs a signal to the outside when the cumulative switching count exceeds a threshold value.

Description

Technical Field

[0001] The present invention relates to a compressor and a method for monitoring the compressor. Background Art

[0002] In electromagnetic switches (electromagnetic switches), when the contacts are opened to shut off a motor, for example, the current that was previously flowing continues to flow, generating sparks that wear out the contacts. This phenomenon becomes more pronounced with higher currents, shortening the life of the electromagnetic switch.

[0003] To address this phenomenon, Patent Document 1 discloses a load control device that records the number of switching times by applying a larger correction to the added value of the number of switching times when the current (main circuit current) when the contacts of an electromagnetic switch (electromagnetic contactor) are higher when the contacts are cut off, thereby accurately grasping the remaining life of the electromagnetic switch.

[0004] Prior art literature

[0005] Patent Literature

[0006] Patent Document 1: Japanese Patent Application Laid-Open No. 6-78438 Summary of the Invention

[0007] Technical problem to be solved by the invention

[0008] However, in compressor electromagnetic switches, the current that flows momentarily when the contacts touch (inrush current, also known as surge current) is often larger than the current that flows when the contacts are open (circuit current), and the magnitude of the inrush current significantly affects the remaining life.

[0009] Furthermore, Patent Document 1 states that when an electromagnetic switch is closed, the temperature of the contacts rises due to continuous operation. Arc discharge generated during disconnection strikes the heated contacts, causing contact wear and shortening their lifespan. However, in compressors, intermittent operation is controlled to keep tank pressure within a specified range, resulting in frequent on / off cycles within a short period of time. Therefore, the contact temperature rise caused by the rated current is less likely to occur, and the shortening of the lifespan due to the interruption current is less likely to occur. This is believed to be the reason why, in compressors, inrush current has a greater impact on the remaining lifespan than the interruption current.

[0010] That is, in a compressor, the inrush current has a greater influence on the remaining life of the electromagnetic switch than the trip current, and the correction based only on the trip current in Patent Document 1 makes it difficult to accurately grasp the remaining life.

[0011] An object of the present invention is to provide a compressor capable of accurately grasping the remaining life of an electromagnetic switch of the compressor.

[0012] Technical solutions to problems

[0013] In order to achieve the above-mentioned purpose, the present invention provides a compressor, which includes: a compressor body housed in a shell; an electric motor that drives the above-mentioned compressor body; an electromagnetic switch that switches a circuit for supplying current to the above-mentioned motor; a temperature sensor arranged in the above-mentioned shell; and a control device that counts the switching of the above-mentioned electromagnetic switch and stores the cumulative number of switching times, and controls the above-mentioned electromagnetic switch, the above-mentioned control device corrects the switching count value of the above-mentioned electromagnetic switch according to the detected temperature of the above-mentioned temperature sensor, and outputs a signal to the outside when the above-mentioned cumulative number of switching times exceeds a threshold value.

[0014] Effects of the Invention

[0015] According to the present invention, the remaining life of the electromagnetic switch of the compressor can be grasped with high accuracy, thereby improving the accuracy of compressor maintenance management. Other problems, structures, and effects than those described above will become clear from the following description of the embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 This is a front view showing a portion of a front panel of the compressor according to the first embodiment of the present invention.

[0017] Figure 2 It is a partial cross-sectional view of the compressor body in a loaded state.

[0018] Figure 3 It is a partial cross-sectional view of the compressor body in the unloaded state.

[0019] Figure 4 This is a control circuit diagram of a compressor according to the first embodiment of the present invention.

[0020] Figure 5 This is a timing chart schematically showing the operation of the electric motor and the pressure in the tank when the control device executes intermittent operation control.

[0021] Figure 6 This is a timing chart schematically showing the operation of the electric motor and the pressure in the tank when the control device executes continuous operation control.

[0022] Figure 7 This is a diagram showing an example of a flowchart of a switching process of an electromagnetic switch and a life determination process of the electromagnetic switch executed by the control device of the first embodiment.

[0023] Figure 8 This is a diagram showing an example of a flowchart of a switching process of an electromagnetic switch and a life determination process of the electromagnetic switch executed by the control device of the second embodiment.

[0024] Figure 9This is a table showing an example of the inrush current of the electric motor mounted on the compressor.

[0025] Figure 10 This is a table showing an example of a combination of a rated current and a rated number of electrical switch durability of an electromagnetic switch mounted on a compressor.

[0026] Figure 11 This table shows an example of the types of electric motors and electromagnetic switches installed in compressors, correction coefficients for the electrical switch durability counts of the electromagnetic switches, and corrected electrical switch durability counts (values ​​obtained by multiplying the rated electrical switch durability counts by the correction coefficients).

[0027] Figure 12 This is a diagram showing an example of the flow of a switching process of an electromagnetic switch and a life determination process of the electromagnetic switch executed by the control device of the third embodiment.

[0028] Figure 13 This is a diagram showing an example of the flow of a switching process of an electromagnetic switch and a life determination process of the electromagnetic switch executed by the control device of the fourth embodiment.

[0029] Figure 14 This is a diagram showing an example of the flow of a switching process of an electromagnetic switch and a life determination process of the electromagnetic switch executed by the control device of the fifth embodiment. DETAILED DESCRIPTION

[0030] Hereinafter, the structure and operation of the compressor according to the first to fifth embodiments of the present invention will be described with reference to the drawings.

[0031] (First embodiment)

[0032] Figure 1 This is a front view showing a portion of the front panel of the compressor 10 according to the first embodiment of the present invention. The compressor 10 according to this embodiment is, for example, a reciprocating air compressor that compresses air by reciprocating a piston.

[0033] like Figure 1 As shown, the compressor 10 is provided with: a compressor body 1 that sucks in and compresses air; an electric motor 2 that drives the compressor body 1; a tank 3 that stores the air compressed by the compressor body 1; a housing 4 that fixes and accommodates these devices; an unloading device 5 that reduces the starting load of the compressor body 1; an electromagnetic switch 6 that switches the circuit that supplies current to the electric motor 2; a control device 7 that controls the compressor 10; and a stop valve 8 that opens and closes the pipe that discharges the compressed air stored in the tank 3 to the outside of the compressor 10.

[0034] The compressor body 1 is housed in the housing 4, and the piston reciprocates to suck air into the cylinder 11 and compress it, and discharge the compressed air into the tank 3. The compressor body 1 is provided with a cylinder 11 and a cylinder head 12 (see Figure 2 、 Figure 3 ).

[0035] The motor 2 is, for example, an induction motor and is connected to a power supply via an electromagnetic switch 6. When the motor 2 is driven, a pulley fixed to the output shaft of the motor 2 rotates a pulley 13 fixed to the crankshaft of the compressor body 1 via, for example, a V-belt 21, causing the piston to reciprocate.

[0036] Tank 3 is a device that stores compressed air and balances the pulsation of the compressed air discharged from compressor body 1, supplying compressed air to the customer's equipment. Tank 3 is equipped with a pressure sensor (described later) that detects the pressure within tank 3. Furthermore, a drain device 32 is provided at the bottom of tank 3 to drain any liquid accumulated within tank 3 to the outside. Tank 3 can also be equipped with an external tank to increase its capacity.

[0037] The housing 4 is a plurality of substantially plate-shaped members that cover the compressor 10 from six sides, and includes a base 41 , a front panel 42 , a left side panel 43 , a right side panel 44 , a rear panel 45 , and an upper panel 46 .

[0038] A stand 47 is fixed to the base 41 via vibration-isolating rubber. The motor 2 is fixed to the stand 47 with bolts, and a mounting base 48 is welded thereto. The compressor body 1 is fixed to the mounting base 48 with bolts, and the tank 3 is fixed to the left side of the mounting base 48 with bolts.

[0039] In addition, the front panel 42 is equipped with a start / stop switch 72 and a display 73 of the control device 7 described later, the left side panel 43 is equipped with a stop valve 8, and the air intake 12a (see FIG. Figure 2 、 3 ) A temperature sensor 9 is installed near it.

[0040] The unloading device 5 is used to open the suction valve 12c by force (refer to Figure 2 、 3 ) and makes the compressor body 1 into an unloaded state (unloaded state). The unloading device 5 of this embodiment includes a three-way electromagnetic valve 51, an unloading pipe 52, and an unloading piston 53 (see Figure 2 、 3 ). In addition, the structure of the unloading device 5 is not limited to the structure exemplified here as long as it can open and close the suction valve 12c according to the command of the control device 7.

[0041] The three-way solenoid valve 51 switches the connection destination of the unloading pipe 52 between the tank 3 and the outside air in response to a command (control signal) output from the control device 7. The unloading pipe 52 connects the three-way solenoid valve 51 to the unloading piston 53. The unloading piston 53 will be described later.

[0042] Figure 2 is a partial cross-sectional view of the compressor body 1 in a loaded state, Figure 3 It is a partial cross-sectional view of the compressor body 1 in the unloaded state.

[0043] The compressor body 1 includes a cylindrical cylinder 11 in which a piston reciprocates, and a cylinder head 12 attached to the front end of the cylinder 11 for sucking air and discharging compressed air.

[0044] The cylinder head 12 is provided with an air intake port 12 a for taking in air through a filter and an air discharge port 12 b for discharging compressed air, and is also provided with a suction valve 12 c , a discharge valve 12 d , and an unloading piston 53 .

[0045] The suction valve 12c is a valve arranged between the air inlet 12a and the opening of the cylinder 11. If the pressure in the compression chamber 11a is lower than the air pressure in the air inlet 12a during the descent of the piston, the valve opens due to the pressure difference and air is taken into the interior of the cylinder 11.

[0046] The discharge valve 12d is a valve arranged between the air discharge port 12b and the opening of the cylinder 11. If the pressure in the compression chamber 11a rises higher than the air pressure in the air discharge port 12b during the rise of the piston, the valve opens due to the pressure difference, allowing the compressed air in the cylinder 11 to be discharged from the air discharge port 12b.

[0047] The unloading piston 53 is one of the components constituting the unloading device 5. Figure 3 Force open as shown Figure 2 The closed intake valve 12c shown opens the compression chamber 11a of the compressor body 1, maintaining the unloaded state (unloaded state). The unloading piston 53 is provided with a pipe connection port for connecting to the unloading pipe 52, and a protrusion 53a that opens the intake valve 12c due to the compressed air flowing in from the pipe connection port. The unloading piston 53 thus configured is fixed to the cylinder head 12 so that the tip of the protrusion 53a contacts the intake valve 12c.

[0048] Figure 4 : is a control circuit diagram of the compressor 10 of this embodiment. Figure 4As shown, the control circuit of the compressor 10 includes: a pressure sensor 31 for measuring the pressure in the tank 3; a three-way solenoid valve 51 for switching the connection target of the unloading piping 52; an electromagnetic switch 6 for switching the circuit AC1 for supplying current from the power supply AC to the motor 2; a temperature sensor 9 for detecting an abnormality of the compressor 10; and a control device 7 for controlling the three-way solenoid valve 51, the electromagnetic switch 6, etc.

[0049] The pressure sensor 31 is a sensor that detects the pressure in the tank 3 as described above, and is electrically connected to the control device 7 . The pressure value in the tank 3 detected by the pressure sensor 31 is transmitted to the control device 7 .

[0050] As described above, the three-way solenoid valve 51 is used to connect the unloading pipe 52 (see Figure 1 ) is switched to a solenoid valve whose connection target is either the tank 3 or the atmosphere, and operates according to the instruction of the electrically connected control device 7.

[0051] The electromagnetic switch 6 is a device that switches a circuit by the action of an electromagnet and cuts off the circuit when an overload is applied. The electromagnetic switch 6 has a contact 61 and a thermal relay 62 and is electrically connected to the motor 2 and the control device 7 .

[0052] The contact 61 is a portion that opens and closes the circuit. In this embodiment, an A contact (a contact that is open (OFF state) when current does not flow through the coil (normally) and closed (ON state) by allowing current to flow through the coil) is used. The circuit is closed according to the instruction of the control device 7 to supply current to the motor 2.

[0053] The thermal relay 62 is a relay that uses heat generated by current to open and close contacts in order to protect the motor 2 from overload. When an excessive current flows through the motor 2, the contacts 61 open to cut off the circuit in order to prevent burnout.

[0054] The temperature sensor 9 is, for example, mounted on the air intake port 12a in the housing 4 (see Figure 2 、 3 ) is installed on the inner side of the rear panel 45 near the compressor 10. In this embodiment, the value detected by the temperature sensor 9 is not only used to detect abnormalities in the compressor 10, but also used in a correction mechanism to improve the accuracy of the switch count value of the electromagnetic switch 6 counted to understand the remaining life of the electromagnetic switch 6. In addition, in this embodiment, the air intake 12a (see Figure 2 、 3 The temperature detected by the temperature sensor 9 on the inner side surface of the rear panel 4 near the compressor 10 is used to correct the life of the electromagnetic switch 6. However, a temperature sensor other than the temperature sensor 9 may be installed on the electromagnetic switch 6 to detect the temperature of the electromagnetic switch 6.

[0055] As described above, the control device 7 controls the three-way electromagnetic valve 51, the electromagnetic switch 6, etc. based on the detection values ​​of the pressure sensor 31 and the temperature sensor 9. The control device 7 includes a control substrate 71, an operation / stop switch 72, a display 73, and an electronic circuit 74.

[0056] The control substrate 71 is a printed wiring board, on which a start / stop switch 72 , a display 73 , and an electronic circuit 74 are mounted.

[0057] The start / stop switch 72 is a switch for starting the operation of the compressor 10 that is stopped, or for stopping the compressor 10 that is in operation.

[0058] The display 73 is a device that displays characters and images based on an electric signal sent from the electronic circuit 74. The display 73 of this embodiment can also display the life of the electromagnetic switch 6.

[0059] Electronic circuit 74 controls electrically connected devices and includes a processing device 75, a storage device 76, electrical components such as resistors, capacitors, and oscillation circuits, and power elements such as transistors and relays. Pressure sensor 31, three-way solenoid valve 51, solenoid switch 6, and temperature sensor 9 are electrically connected to electronic circuit 74.

[0060] The processing device 75 is a processor such as a CPU (Central Processing Unit) mounted on a microcomputer, FPGA (Field Programmable Gate Array), or other device. The processing device 75 processes the detection value transmitted from the pressure sensor 31 into a command to the electromagnetic switch 6 or the three-way electromagnetic valve 51. Furthermore, the processing device 75 counts the number of times the electromagnetic switch 6 switches on and off, corrects the count based on the detection value transmitted from the temperature sensor 9, and transmits the corrected count to the storage device 76. If the cumulative number of times the electromagnetic switch 6 switches on and off, as stored in the storage device 76, exceeds a threshold, the processing device 75 outputs a signal to the outside.

[0061] The storage device 76 stores the control application program of the processing device 75, the number of switching times related to the life of the electromagnetic switch 6 calculated taking into account the inrush current, the cumulative number of switching times of the electromagnetic switch 6 counted by the processing device 75, and the like. The storage device 76 can be a RAM (Random Access Memory) for processing and storing data, or a ROM (Read Only Memory) for pre-storing the control application program. Furthermore, the storage device 76 must be updated and store the cumulative number of switching times of the electromagnetic switch 6 each time. It must be rewritable and maintain the cumulative number of switching times of the electromagnetic switch 6 even when the AC power is turned off. Therefore, the storage device 76 is preferably a rewritable nonvolatile memory, such as an HDD (Hard Disk Drive) or SSD (Solid State Drive).

[0062] Figure 5 It is a timing chart schematically showing the operation of the electric motor 2 and the pressure in the tank 3 when the control device 7 executes the intermittent operation control. Figure 6 It is a timing chart schematically showing the operation of the electric motor 2 and the pressure in the tank 3 when the control device 7 executes the continuous operation control.

[0063] When the controller 7 detects that the pressure value of the tank 3, detected by the pressure sensor 31, has reached a predetermined stop pressure Poff during operation of the compressor 10, it controls either the electromagnetic switch 6 or the three-way electromagnetic valve 51. When the controller 7 controls the electromagnetic switch 6, the intermittent operation control mode is used; when the controller 7 controls the three-way electromagnetic valve 51, the continuous operation control mode is used. The intermittent operation control mode and the continuous operation control mode are described below.

[0064] (Intermittent operation control method)

[0065] When the control device 7 detects that the pressure value of the tank 3 detected by the pressure sensor 31 during the operation of the compressor 10 reaches the predetermined stop pressure Poff, the control device 7 performs an open circuit control to separate the contact 61 from the electromagnetic switch 6. As a result, the power supply to the motor 2 is stopped. Figure 5 As shown, the motor 2 stops, the power to the compressor body 1 is lost, and the work of compressing air in the compressor body 1 stops.

[0066] After the compressor body 1 stops, the compressed air in the tank 3 is consumed by the operation of the customer's equipment connected to the shutoff valve 8 , and eventually reaches the recovery pressure Pon.

[0067] When the control device 7 detects that the pressure value of the tank 3 detected by the pressure sensor 31 reaches the recovery pressure Pon after the motor 2 stops, the control device 7 performs a closed circuit control to make the contact 61 contact the electromagnetic switch 6. As a result, the power supply to the motor 2 is restarted. Figure 5 As shown, the electric motor 2 is started, the power to the compressor body 1 is restored, and the work of compressing air in the compressor body 1 starts again.

[0068] This method stops the motor when the pressure in tank 3 reaches the stop pressure Poff, thus reducing power consumption. However, since the motor 2 is restarted at the recovery pressure Pon, the electromagnetic switch 6 frequently switches on and off, potentially shortening its lifespan.

[0069] (Continuous operation control mode)

[0070] When the control device 7 detects that the pressure value of the tank 3 detected by the pressure sensor 31 during the operation of the compressor 10 reaches the predetermined stop pressure Poff, it controls the unloading pipe 52 and the tank 3 to communicate with the three-way electromagnetic valve 51. As a result, the compressed air in the tank 3 flows into the unloading pipe 52. The compressed air flowing into the unloading pipe 52 causes the protrusion 53a of the unloading piston 53 to protrude. The protruding protrusion 53a presses the suction valve 12c to forcibly open it (see Figure 3 ).

[0071] By opening the suction valve 12c, the compressed air in the compression chamber 11a is released to the outside through the suction valve 12c and is not discharged to the tank 3 through the air discharge port 12b, so the supply of compressed air from the compressor body 1 to the tank 3 stops. Figure 6 As shown, the motor 2 is continuously operated while being kept in the ON state, and the power of the motor 2 does not become zero even if it decreases due to no-load operation (unload operation).

[0072] That is, the controller 7 in the continuous operation control mode operates the unloader 5 to forcibly open the suction valve 12c, stops the supply of compressed air from the compressor body 1 to the tank 3, performs no-load operation, and continuously operates the motor 2.

[0073] After the supply of compressed air from the compressor body 1 to the tank 3 is stopped, the air is consumed by the operation of the customer's equipment connected to the shutoff valve 8 , and eventually reaches the recovery pressure Pon.

[0074] When the control device 7 detects that the pressure value of the tank 3 detected by the pressure sensor 31 reaches the recovery pressure Pon after the motor 2 stops, the control device 7 stops the unloading device 5 and controls the suction valve 12 c to be forcibly kept open.

[0075] Specifically, the control device 7 controls the three-way solenoid valve 51 to connect the unloading pipe 52 to the atmosphere. This releases the compressed air in the unloading pipe 52 to the atmosphere, retracts the protrusion 53a of the unloading piston 53, and prevents the intake valve 12c from being forcibly opened. Consequently, the compressed air in the compression chamber 11a is not released to the outside air through the intake valve 12c, but is discharged from the air outlet 12b into the tank 3, resuming the supply of compressed air from the compressor body 1 to the tank 3.

[0076] This continuous operation control method is used to suppress the load on the electromagnetic switch 6, etc. when the motor 2 is repeatedly stopped and started in a short period of time (for example, when the amount of air discharged by the compressor body 1 is small relative to the amount of air consumed by the customer's equipment, or when the volume of the tank 3 is small).

[0077] That is, the continuous operation control mode is a mode in which no-load operation is performed when the pressure of the tank 3 reaches the stop pressure Poff and normal load operation is returned to when the pressure reaches the recovery pressure Pon, without performing opening and closing control of the electromagnetic switch 6.

[0078] This method does not stop the motor 2 even when the pressure in the tank 3 reaches the stop pressure Poff, resulting in high power consumption. However, since the electromagnetic switch 6 does not repeatedly open and close, the burden on the electromagnetic switch 6 is reduced. Furthermore, by cooling the compressor body 1 with a pulley fan directly connected to the crankshaft, the compressor body 1 can be continuously cooled.

[0079] Figure 7 1 is a diagram showing an example of the flow of a switching process of the electromagnetic switch 6 and a process for determining the life of the electromagnetic switch 6 executed by the control device 7 of the present embodiment.

[0080] The control device 7 counts the number of times the electromagnetic switch 6 is opened and closed, stores the accumulated number of openings and closings, and controls the electromagnetic switch 6. Furthermore, the control device 7 corrects the count value of the number of times the electromagnetic switch 6 is opened and closed based on the temperature detected by the temperature sensor 9, and outputs a signal to the outside when the accumulated number of openings and closings exceeds a threshold value.

[0081] Specifically, the processing unit 75 of the control device 7 executes the following operations based on the program stored in the storage device 76, the ambient temperature Ta of the electromagnetic switch 6 in the housing 4 detected by the temperature sensor 9, and the pressure Pt in the tank 3 detected by the pressure sensor 31. Figure 7 The processing shown.

[0082] First, the operation of the compressor 10 is started by operating the operation button of the operation / stop switch 72. Figure 7 In the process, the processing device 75 makes the contact 61 contact in step 1 to close the electromagnetic switch 6 and start the motor 2.

[0083] Next, in step 2, the processing device 75 determines whether the ambient temperature Ta of the electromagnetic switch 6, detected by the temperature sensor 9, exceeds a predetermined temperature (hereinafter referred to as the temperature threshold T1). The temperature threshold T1 is the upper limit of the temperature detected by the temperature sensor 9 that does not affect the life of the electromagnetic switch 6.

[0084] If the ambient temperature Ta does not exceed the temperature threshold value T1 (No), the processing device 75 counts the detected switching number of the electromagnetic switch 6 as 1 in step 3 and adds 1 to the cumulative switching number stored in the storage device 76 .

[0085] If the ambient temperature Ta exceeds the temperature threshold T1 (YES), the processing device 75, in step 4, adds a value corrected by the difference between the detected temperature (ambient temperature Ta) and the temperature threshold T1 to the cumulative number of switching operations of the electromagnetic switch 6, in order to account for the effect of the ambient temperature Ta on the life of the electromagnetic switch 6. Specifically, for example, (Ta - T1) × 0.05 is added to the detected number of switching operations of the electromagnetic switch 6, and this value is added to the cumulative number of switching operations. Therefore, if the ambient temperature Ta exceeds the temperature threshold T1 (YES), the processing device 75 corrects the switching count of the electromagnetic switch 6 to a larger value as the temperature detected by the temperature sensor 9 increases.

[0086] Next, the processing device 75 determines in step 5 whether the cumulative number of switching operations is greater than or equal to a switching number threshold. The switching number threshold in this embodiment is the number of times the electromagnetic switch 6 has been operated for the electrical life of the electromagnetic switch 6. Specifically, it is the rated number of times the electromagnetic switch 6 has been operated for the rated electrical life of the electromagnetic switch 6 when the rated load is connected to the electromagnetic switch 6.

[0087] The processing device 75 proceeds to step 6 if the cumulative switching count is equal to or greater than the electrical switching durability count of the electromagnetic switch 6 (yes), and skips steps 6 and 7 and proceeds to step 8 if the cumulative switching count is not greater than the electrical switching durability count of the electromagnetic switch 6 (no).

[0088] In step 6, the processing device 75 outputs a signal to the outside world, notifying the electromagnetic switch of its end of life. Examples of such externally output signals include display 73 mounted on the housing 4 indicating the life of the electromagnetic switch 6, or notification to a remote device via wireless communication. Specifically, in step 6, the processing device 75 performs at least one of a process of displaying the end of life of the electromagnetic switch 6 on the display 73 or a process of notifying the remote device of the end of life via wireless communication. After executing step 6, the processing device 75 proceeds to step 7.

[0089] Step 7 determines whether the user has responded to the life notification of electromagnetic switch 6 in step 6. If the user has responded and pressed the stop button of the run / stop switch 72 in step 7 (Yes), the compressor 10 stops operating and the process ends. If the user has not responded to the life notification of electromagnetic switch 6 (No), the process proceeds to step 8.

[0090] In step 5, if it is determined that the cumulative number of switching times does not exceed the electrical switch durability number of the electromagnetic switch 6 (No), or if the user does not respond to the notification of the life of the electromagnetic switch 6 in step 7 (No), the processing device 75 controls the intermittent operation of the compressor 10 in steps 8 to 1.

[0091] Specifically, in step 8, the processing device 75 operates the motor 2 until the pressure Pt in the tank 3, as detected by the pressure sensor 31, reaches the stop pressure Poff. When the pressure Pt reaches or exceeds the stop pressure Poff, in step 9, the processing device 75 separates the contacts 61, opening the electromagnetic switch 6 to stop the motor 2. In step 10, the motor 2 is stopped until the pressure Pt in the tank 3, as detected by the pressure sensor 31, reaches the recovery pressure Pon. When the pressure Pt reaches the recovery pressure Pon, the processing device 75 returns to step 1, contacts the contacts 61, closes the electromagnetic switch 6, and starts the motor 2.

[0092] Furthermore, the processing device 75 executes steps 1 to 10 until the user responds in step 7 .

[0093] (Effect)

[0094] In the compressor 10, the electromagnetic switch 6 generates heat due to the current flowing when the electromagnetic switch 6 is switched on and off. However, compared with the circuit-breaking current generated when the electromagnetic switch 6 is opened (when the motor 2 is switched from on to off), the inrush current generated when the electromagnetic switch 6 is closed (when the motor is switched from off to on) is larger, and the heating of the electromagnetic switch 6 is mainly caused by the magnitude of the inrush current.

[0095] Furthermore, in the compressor 10 , the electric motor 2 is frequently turned on and off. Therefore, the heat generated by the electromagnetic switch 6 due to the inrush current becomes more significant, and the temperature inside the casing is likely to rise.

[0096] Therefore, in the compressor 10 of the present embodiment, the effect of the detected temperature of the temperature sensor 9 provided in the housing 4 on the life of the electromagnetic switch 6 is set to, for example, (Ta-T1)×0.05 times, and the value of the count of the switching of the electromagnetic switch 6 is added to the cumulative number of switching times by adding 1. When the cumulative number of switching times reaches the switching number threshold, it is notified that the electromagnetic switch 6 has reached the end of its life.

[0097] In this way, when the heat generated by the electromagnetic switch 6 accompanying the on / off operation of the motor 2 is estimated based on the detected temperature of the temperature sensor 9, and the switching count value of the electromagnetic switch 6 is corrected based on the detected temperature to manage the cumulative number of switching times, the shortening of the life of the electromagnetic switch 6 caused by the frequent inrush currents generated by the intermittent operation of the motor 2 can be taken into account, so that the remaining life of the electromagnetic switch 6 can be grasped with high precision.

[0098] That is, according to the present embodiment, the remaining life of the electromagnetic switch 6 of the compressor 10 can be grasped with high accuracy, thereby improving the accuracy of maintenance management of the compressor.

[0099] Furthermore, the compressor 10 of this embodiment can use the temperature sensor 9 installed at the compressed air intake port of a standard compressor 10 as the "temperature sensor 9 provided within the casing," for example. Therefore, there is no need to provide a new current sensor for detecting inrush current. Therefore, the existing structure of multiple compressors 10 can be utilized to address this issue, thus suppressing cost increases.

[0100] Furthermore, the electromagnetic switch lifespan is notified, for example, via a display. This differs from warnings such as alarms that require replacement when the electromagnetic switch reaches its end of life. This allows for the predicted replacement period, similar to the replacement of consumables such as filters and oil, allowing for planned replacement of the electromagnetic switch 6. Furthermore, the electromagnetic switch lifespan can be communicated to a remote device via wireless communication. For example, by transmitting the electromagnetic switch lifespan notification to a portable device of a maintenance person or uploading it to the cloud, the person in charge can be informed of the compressor lifespan and can provide services such as recommended maintenance to the user.

[0101] In the above description, the compressor 10 includes the unloader 5. However, the switching process of the electromagnetic switch 6 and the life determination process of the electromagnetic switch 6 in this embodiment can be executed even without the unloader 5, and the compressor 10 does not need to include the unloader 5.

[0102] (Second embodiment)

[0103] Figure 8 This figure shows an example of a flow of electromagnetic switch switching processing and electromagnetic switch life determination processing executed by a compressor control device according to a second embodiment of the present invention. The compressor of this embodiment differs from the compressor 10 of the first embodiment in the following points.

[0104] That is, the compressor 10 of the first embodiment notifies the life of the electromagnetic switch 6 when the cumulative number of opening and closing times of the electromagnetic switch 6 whose count value is corrected according to the temperature detected by the temperature sensor 9 becomes equal to or greater than the electrical switch durability number.

[0105] On the other hand, the compressor of this embodiment notifies the life of the electromagnetic switch 6 when the cumulative number of switching times of the electromagnetic switch 6 counted without correction is greater than the corrected electric switch endurance number obtained by correcting the rated electric switch endurance number of the electromagnetic switch 6 based on the inrush current of the motor 2 and the rated current of the electromagnetic switch 6 (if the answer is "yes" in step 205).

[0106] Specifically, in step 1, the processing device 75 of this embodiment does not perform step 2 of the first embodiment (determining whether the ambient temperature Ta exceeds the temperature threshold T1) after closing the electromagnetic switch 6. In step 3, the detected number of switching times of the electromagnetic switch 6 is counted as 1, and 1 is added to the cumulative number of switching times stored in the storage device 76.

[0107] Next, in step 205, the processing device 75 determines whether the cumulative number of switching times is greater than the corrected electric switch endurance times obtained by correcting the rated electric switch endurance times of the electromagnetic switch 6 based on the inrush current of the motor 2 and the rated current of the electromagnetic switch 6. If the cumulative number of switching times is greater than the corrected electric switch endurance times (yes), the process proceeds to step 6; if the cumulative number of switching times is less than the corrected electric switch endurance times (no), the process proceeds to step 8.

[0108] Here, use Figures 9 to 11 The corrected electric switch durability count obtained by correcting the rated electric switch durability count of the electromagnetic switch 6 will be described.

[0109] Figure 9 This is a table showing an example of the inrush current of the electric motor 2 mounted on the compressor. Figure 10 This is a table showing an example of a combination of a rated current and a rated number of electrical switch durability of the electromagnetic switch 6 mounted on the compressor. Figure 11 This table shows an example of the types of the electric motor 2 and electromagnetic switch 6 mounted in the compressor, the correction coefficient of the electric switch durability count of the electromagnetic switch 6 , and the corrected electric switch durability count (a value obtained by multiplying the rated electric switch durability count by the correction coefficient).

[0110] like Figure 9 As shown in FIG. 1 , the inrush current varies depending on the output of the motor 2 mounted on the compressor and the compressor mode (compressor type). Figure 10 As shown, the electromagnetic switches 6 include electromagnetic switches having different combinations of rated current and rated electrical switch durability times, and the electromagnetic switch model numbers in the figure represent identifiers of these combinations.

[0111] like Figure 9As shown in FIG. 1 , the inrush current varies depending on the output of the motor 2 mounted on the compressor and the compressor type (compressor type). In addition, since the required current varies depending on the number of turns, number of poles, etc. of the motor, the inrush current of a high-power motor is not necessarily large. Therefore, in this embodiment, the output β of the No. 2 motor may be larger than the output γ of the No. 3 motor. In addition, as Figure 10 As shown, the rated current and rated number of electrical switching durability of the electromagnetic switch 6 mounted on the compressor vary depending on the model.

[0112] On the other hand, the electrical durability index of the electromagnetic switch 6 is specified to close at six times the rated current of the contact 61 and to open at one times the rated current of the contact 61. Therefore, if the inrush current exceeds six times the rated current, the electrical switching durability count of the electromagnetic switch 6 is considered to be reduced. Therefore, in this embodiment, if the inrush current of the motor 2, determined based on the type of compressor 10 and the output power of the motor 2, exceeds six times the rated current of the mounted electromagnetic switch 6, the corrected electrical switching durability count used in step 205 is corrected to a value smaller than the electrical switch durability count (e.g., the rated electrical switching durability count).

[0113] Furthermore, the inventors believe that the reduced life span (number of electrical switch durability) L′c of the electromagnetic switch 6 can be calculated by the following formula.

[0114] [Formula 1]

[0115]

[0116] In the above formula 1, Is is the inrush current of the motor 2 (A), Ie is the rated current of the electromagnetic switch 6 (A), Lc is the rated switching endurance number of the electromagnetic switch 6 (times), and f ON-OFF is the switching frequency of the electromagnetic switch 6 (times / h).

[0117] The lifespan L'c of the electromagnetic switch 6 calculated using the above formula varies depending on the inrush current and the rated current. The inrush current varies depending on the output of the motor 2. Furthermore, the motor 2 and electromagnetic switch 6 installed in the compressor vary depending on the compressor model, so the lifespan L'c of the electromagnetic switch 6 also varies depending on the compressor model. For example, the lifespan L'c of the electromagnetic switch 6 in a small air compressor is 50-100% of the rated number of electrical switching cycles. Some compressors even reach the end of their lifespan at half the rated number of cycles.

[0118] Furthermore, the number of electrical switching cycles of the electromagnetic switch 6 varies depending on conditions such as the load capacity (contact voltage, contact current), type, switching frequency, and ambient temperature. Furthermore, during contact switching, inrush currents can be generated, several to dozens of times greater than the normal current, depending on the load type. Therefore, the lifespan of the electromagnetic switch 6 varies significantly depending on the inrush current conditions.

[0119] Specifically, in this embodiment, a correction coefficient is calculated based on the model and usage method of the compressor, and the correction coefficient is multiplied by the rated electric switch durability number of the electromagnetic switch, thereby precalculating the corrected electric switch durability number, and the corrected electric switch durability number is stored in the storage device 76 of the control device 7.

[0120] For example, in the compressor mode A and equipped with a motor 2 with power β ( Figure 9 No.2) and electromagnetic switch 6 with a rated current of 5 amperes ( Figure 10 No.1 electromagnetic switch model a) compressor ( Figure 11 In No.2), the inrush current of motor 2 is based on Figure 9 The inrush current of the motor 2 is 45 amperes, which is 9 times greater than the rated current of the electromagnetic switch 6. Therefore, it is believed that the life of the electromagnetic switch of the compressor is from Figure 10 The rated electrical switching durability of the electromagnetic switch shown in No. 1 is reduced to 200,000 times.

[0121] In this case, the correction factor of 0.7 calculated based on the compressor model and usage is Figure 10 The rated electric switch durability number of the electromagnetic switch shown in No. 1 is multiplied by 200,000 times, and the corrected electric switch durability number is calculated in advance to be 140,000 times and stored in the storage device 76 of the control device 7 in advance.

[0122] On the other hand, in the compressor mode A and equipped with a motor 2 with a power of βkW ( Figure 9 No.2) and electromagnetic switch 6 with a rated current of 10 amperes ( Figure 10 In the compressor with the No.2 electromagnetic switch model b), the inrush current of the motor (45 amps) is 4.5 times the rated current of the electromagnetic switch (10 amps), which is less than 6 times. Therefore, it is believed that the life of the electromagnetic switch 6 installed in this compressor will not be shortened. Figure 10 The rated electrical switch durability number of the electromagnetic switch shown in No. 2 is reduced by 200,000 times. In this case, the rated electrical switch durability number of the electromagnetic switch (200,000 times) is stored in the storage device 76 as the corrected electrical switch durability number.

[0123] [Effect]

[0124] The compressor of this embodiment notifies the user of the life of electromagnetic switch 6 when the cumulative number of switching cycles exceeds a corrected electrical switch durability calculated using the motor's inrush current, the electromagnetic switch's rated current, and the rated electrical switch durability. Therefore, the electromagnetic switch's life can be accurately determined using the motor's inrush current, the electromagnetic switch's rated current, and the rated electrical switch durability, improving the accuracy of compressor maintenance and management.

[0125] Furthermore, since the influence of the inrush current is reflected in the life of the electromagnetic switch without using a high-performance electrical sensor capable of detecting the value of the inrush current, the remaining life of the electromagnetic switch 6 can be accurately grasped at no cost.

[0126] (Third embodiment)

[0127] Figure 12 This figure shows an example of a flow of electromagnetic switch switching processing and electromagnetic switch life determination processing executed by a compressor control device according to a third embodiment of the present invention. The compressor of this embodiment differs from the compressor 10 of the first embodiment in the following points.

[0128] Specifically, the switching count threshold for the compressor 10 in the first embodiment is the rated electrical switching endurance count of the electromagnetic switch 6. In step 5, a determination is made as to whether the cumulative switching count of the electromagnetic switch 6 is greater than or equal to the rated electrical switching endurance count. In contrast, in the compressor of the present embodiment, the switching count threshold is the corrected electrical switching endurance count obtained by correcting the rated electrical switching endurance count of the electromagnetic switch 6 based on the inrush current of the motor 2 and the rated current of the electromagnetic switch 6. Similar to the second embodiment, a determination is made as to whether the cumulative switching count of the electromagnetic switch 6 is greater than or equal to the corrected electrical switching endurance count in step 205.

[0129] In addition, in this embodiment, the switching number threshold is the corrected electric switch durability number, and the corrected electric switch durability number is corrected to a value smaller than the rated electric switch durability number as shown in the second embodiment when the inrush current of the motor 2 exceeds 6 times the rated current of the electromagnetic switch 6 (for example, by multiplying the correction coefficient 0.7 by the rated electric switch durability number).

[0130] [Effect]

[0131] The compressor of this embodiment is as shown in the first embodiment. In step 4, the count value of the switching of the electromagnetic switch 6 is corrected according to the detected temperature of the temperature sensor 9. Moreover, as shown in the second embodiment, in step 205, the cumulative number of switching times of the electromagnetic switch 6 is compared with the corrected electric switch endurance number obtained by correcting the electric switch endurance number of the electromagnetic switch 6 according to the inrush current of the motor 2 and the rated current of the electromagnetic switch 6.

[0132] Therefore, as shown in the first embodiment, the shortened life of the electromagnetic switch 6 caused by the frequent inrush currents associated with the intermittent operation of the motor 2 can be considered. Furthermore, as shown in the second embodiment, the life of the electromagnetic switch can be accurately determined using the motor's inrush current, the electromagnetic switch's rated current, and the rated number of electrical switch endurance tests, thereby improving the accuracy of compressor maintenance and management. Furthermore, because the impact of the inrush current is reflected in the electromagnetic switch's life without the use of a high-performance electrical sensor capable of detecting the inrush current value, the remaining life of the electromagnetic switch 6 can be accurately determined at no cost.

[0133] (Fourth embodiment)

[0134] Figure 13 This figure shows an example of a flow of a switching process of the electromagnetic switch 6 and a process for determining the number of electrical switching durability of the electromagnetic switch 6, executed by the controller 7 of the compressor according to the fourth embodiment of the present invention. The compressor according to this embodiment differs from the compressor 10 according to the first embodiment in the following respects.

[0135] That is, in the first embodiment, when the cumulative number of switching times stored in the storage device 76 exceeds the electrical switching durability number of the electromagnetic switch 6 in step 5 (yes), the processing device 75 notifies the electromagnetic switch 6 of the end of its life through the display of the display 73 in step 6, and enters step 7.

[0136] In contrast, in the present embodiment, in step 5, when the cumulative number of switching times stored in the storage device 76 exceeds the electrical switch durability number of the electromagnetic switch 6 (yes), in step 406, the processing device 75 notifies the electromagnetic switch 6 of the end of its life by displaying on the display 73, etc., and performs at least one of the control of increasing the stop pressure Poff and the control of decreasing the recovery pressure Pon, thereby expanding the difference (pressure range) between the stop pressure Poff and the recovery pressure Pon, and proceeds to step 7.

[0137] In addition, the control of the fourth embodiment can be applied to the second embodiment. Figure 8 In step 205 of the second embodiment shown, step 6 to which the program proceeds when it is determined that the cumulative number of switching times is equal to or greater than the corrected electric switch durability number (yes) is replaced with step 406 .

[0138] (Effect)

[0139] In this embodiment, in step 5, when the cumulative number of switching times stored in the storage device 76 exceeds the electrical switch durability number of the electromagnetic switch 6 (yes), in step 406, the processing device 75 notifies the electromagnetic switch 6 through the display of the display 73, etc. that the electrical switch durability number has been reached, and increases the difference between the stop pressure Poff and the recovery pressure Pon.

[0140] Thus, the number of switching times of the electromagnetic switch 6 can be reduced from the time when the cumulative number of switching times stored in the storage device 76 exceeds the electrical switching durability number of the electromagnetic switch 6 until the user responds to the notification and ends the operation of the compressor.

[0141] For example, before the compressor of this embodiment exceeds the electric switch durability number of the electromagnetic switch 6, the difference between the stop pressure Poff and the recovery pressure Pon is 0.05 MPa, Tcyc (refer to Figure 5 ) is 1 minute, the number of switching times of the electromagnetic switch 6 is 60 times / h.

[0142] On the other hand, if the cumulative number of switching cycles stored in storage device 76 exceeds the electrical switching endurance of electromagnetic switch 6, processing device 75 increases the difference between stop pressure Poff and return pressure Pon by, for example, three times 0.15 MPa in step 406. In this case, Tcyc is 3 minutes, and the number of switching cycles of electromagnetic switch 6 is 20 times / hour, so the number of switching cycles of electromagnetic switch 6 is reduced.

[0143] Therefore, in the compressor of this embodiment, when the cumulative switching times of the electromagnetic switch 6 exceeds the durability times of the electric switch, the switching times of the electromagnetic switch 6 are reduced, thereby extending the period from the notification that the electromagnetic switch 6 has reached the durability times of the electric switch to the time when the electromagnetic switch 6 stops working due to exhaustion of its life, and extending the period for the user to respond to the notification.

[0144] (Fifth embodiment)

[0145] Figure 14 This is a diagram showing an example of the flow of a switching process of the electromagnetic switch 6 and a life determination process of the electromagnetic switch 6 executed by the compressor control device according to the fifth embodiment of the present invention.

[0146] The compressor of this embodiment is different from the compressor 10 of the first embodiment in the following points.

[0147] That is, in the first embodiment, if the user does not respond to the notification of the life of the electromagnetic switch 6 from the processing device 75 in step 7 , the processing device 75 controls the intermittent operation of the compressor 10 (step 8 to step 1 ).

[0148] In contrast, in this embodiment, if the user does not respond to the notification of the life of the electromagnetic switch 6 from the processing device 75 in step 7 , the processing device 75 controls the continuous operation of the compressor 10 (steps 508 to 501 ).

[0149] Specifically, in step 7 , when the user does not respond to the notification of the life of the electromagnetic switch 6 from the processing device 75 (No), the processing device 75 proceeds to step 508 .

[0150] Next, in step 508 , the processing device 75 operates the electric motor 2 until the pressure Pt in the tank 3 detected by the pressure sensor 31 reaches the stop pressure Poff.

[0151] When the pressure Pt reaches or exceeds the stop pressure Poff, the processing device 75 controls the three-way solenoid valve 51 to connect the unloading pipe 52 to the tank 3 (unloading control). As a result, the compressed air in the tank 3 flows into the unloading pipe 52, and the protrusion 53a of the unloading piston 53 connected to the unloading pipe 52 protrudes and presses the suction valve 12c, forcing the suction valve 12c to remain open (see Figure 3 The compressed air in the compression chamber 11a is not discharged from the air outlet 12b to the tank 3 but is released to the outside from the air inlet 12a. Therefore, the supply of compressed air to the tank 3 is stopped while the motor 2 is continuously operated.

[0152] Next, in step 510, the processing device 75 controls the three-way solenoid valve 51 to unload until the pressure Pt within the tank 3, as detected by the pressure sensor 31, reaches the recovery pressure Pon. When the pressure Pt reaches the recovery pressure Pon, the processing device 75 releases the unloading control of the three-way solenoid valve 51 in step 501. Specifically, the processing device 75 controls the three-way solenoid valve 51 to release the unloading pipe 52 from the connection with the tank 3 and connects the unloading pipe 52 to the atmosphere. This releases the compressed air within the unloading pipe 52 to the atmosphere, retracts the protrusion 53a of the unloading piston 53, releases the forced opening of the intake valve 12c, and resumes the supply of compressed air from the compressor body 1 to the tank 3.

[0153] The processing device 75 performs the continuous operation control (steps 508 to 501 ) in step 7 until the user responds to the notification of the life of the electromagnetic switch 6 from the processing device 75 .

[0154] Furthermore, the control of the fifth embodiment can also be applied to the second embodiment. Figure 8 In step 7 of the second embodiment shown, if the user does not respond to the notification of the life of the electromagnetic switch 6 from the processing device 75 , the compressor is controlled to be continuously operated (step 508 to step 501 ).

[0155] (Effect)

[0156] In this embodiment, in step 7 , if the user does not terminate the operation of the compressor 10 in response to the notification of the life of the electromagnetic switch 6 from the processing device 75 (No), the processing device 75 controls the continuous operation of the motor 2 (steps 508 to 501 ).

[0157] Thus, after the cumulative number of switching cycles exceeds the electrical switch durability count of electromagnetic switch 6, the electromagnetic switch 6 can be prevented from switching until the user responds to the notification. For example, if a compressor that starts and stops once a minute is operated for 8 hours, the electromagnetic switch 6 will be switched 480 times. On the other hand, the compressor of this embodiment operates continuously after the cumulative number of switching cycles exceeds the electrical switch durability count until the user responds to the notification. Therefore, the electromagnetic switch 6 is switched only once when the compressor is stopped.

[0158] Therefore, in the compressor of this embodiment, after the cumulative number of opening and closing of the electromagnetic switch 6 reaches or exceeds the electric switch durability number, continuous operation control is performed to suppress the opening and closing of the electromagnetic switch 6. Therefore, even after the electromagnetic switch 6 reaches the electric switch durability number, the compressor can be operated continuously for a long period of time, allowing for compressor maintenance such as replacing the electromagnetic switch 6 without delay and in sufficient time.

[0159] Furthermore, the present invention is not limited to the above-described embodiments and includes various variations. For example, the above-described embodiments are described in detail to facilitate understanding of the present invention and are not limited to having all the structures described. In addition, a portion of the structure of a certain embodiment can be replaced with the structure of another embodiment, and the structure of another embodiment can be added to the structure of a certain embodiment. In addition, with respect to a portion of the structure of each embodiment, other structures can be added, deleted, or replaced.

[0160] Furthermore, some or all of the aforementioned structures and functions may be implemented in hardware, for example, by designing them using integrated circuits. Furthermore, the aforementioned structures and functions may be implemented in software by having a processing device (microcomputer) interpret and execute programs that implement the respective functions. Information such as programs, tables, and files that implement the various functions can be stored in a storage device such as a memory, a hard disk, or an SSD (Solid State Drive), or a recording medium such as an IC card, SD card, or DVD.

[0161] Furthermore, the present invention may also be implemented in the following manner. For example, in the above embodiment, the compressor is a reciprocating type. However, this is not limiting and, for example, it may be a screw type or a scroll type, or a booster compressor that receives primary pressure from an external source and recompresses it. Furthermore, in the above embodiment, it is configured as an air compressor. However, this is not limiting and it may also be a compressor for other gases, such as nitrogen.

[0162] Description of Reference Numerals

[0163] 1...compressor body, 11...cylinder, 12c...suction valve, 2...motor, 3...tank, 31...pressure sensor, 4...housing, 45...rear panel, 5...unloading device, 51...three-way solenoid valve, 52...unloading piping, 53...unloading piston, 6...electromagnetic switch, 61...contact, 7...control device, 72...run / stop switch, 73...display, 75...processing device, 76...storage device, 9...temperature sensor, 10...compressor.

Claims

1. A compressor, characterized in that: include: a compressor body housed in the housing; an electric motor for driving the compressor body; an electromagnetic switch for switching a circuit for supplying current to the motor; a temperature sensor disposed in the housing; and a control device that counts the number of times the electromagnetic switch is opened and closed and stores the accumulated number of times the electromagnetic switch is opened and closed, and controls the electromagnetic switch; The control device corrects a count value of the electromagnetic switch on and off based on the temperature detected by the temperature sensor, and outputs a signal to the outside when the cumulative number of on and off times becomes equal to or greater than a threshold value of the number of on and off times.

2. The compressor according to claim 1, characterized in that: The switching count threshold value is a count indicating the number of times the electromagnetic switch can be electrically switched on and off.

3. The compressor according to claim 1, characterized in that: The switching count threshold is a corrected switching durability count obtained by correcting the switching durability count of the electromagnetic switch based on the inrush current of the motor and the rated current of the electromagnetic switch.

4. The compressor according to claim 1, characterized in that: The switching count threshold value is corrected to a smaller value when the inrush current of the electric motor, which is determined based on the type of the compressor and the power of the electric motor, exceeds six times the rated current of the electromagnetic switch.

5. The compressor according to claim 1, characterized in that: The control device corrects the switching count value of the electromagnetic switch to a larger value as the detected temperature of the temperature sensor increases.

6. The compressor according to claim 1, characterized in that: The control device increases the difference between the recovery pressure and the stop pressure of the compressor when the cumulative number of switching operations becomes equal to or greater than the switching number threshold.

7. The compressor according to claim 1, characterized in that: The control device controls the compressor to continuously operate when the cumulative number of on-off cycles becomes equal to or greater than the on-off cycle threshold.

8. The compressor according to claim 1, characterized in that: The control device determines whether the detected temperature of the temperature sensor exceeds a temperature threshold. If the detected temperature exceeds the temperature threshold, the control device corrects the switch count value of the electromagnetic switch by adding a value corrected according to the difference between the detected temperature and the temperature threshold to the switch count value of the electromagnetic switch.

9. The compressor according to claim 1, characterized in that: The temperature sensor is provided at the suction port of the compressor body and detects the temperature of gas sucked into the compressor body.

10. The compressor according to claim 1, characterized in that: The signal output to the outside is a display of the life of the electromagnetic switch by a display provided on the housing, or a notification of the end of the life of the electromagnetic switch to a remote device by wireless communication.

11. A compressor monitoring method, which is the compressor monitoring method according to claim 1, wherein: It is monitored whether the accumulated number of switching times is greater than the rated electric switch durability number or the corrected electric switch durability number.

12. The compressor monitoring method according to claim 11, characterized in that: The count value added to the cumulative number of switching times is corrected using the temperature detected by the temperature sensor.

13. The compressor monitoring method according to claim 11, wherein: The rated electric switch durability number is corrected based on the inrush current of the motor and the rated current of the electromagnetic switch.

14. A compressor, characterized in that: include: a compressor body housed in the housing; an electric motor for driving the compressor body; an electromagnetic switch for switching a circuit for supplying current to the motor; and a control device that counts the number of times the electromagnetic switch is opened and closed and stores the accumulated number of times the electromagnetic switch is opened and closed, and controls the electromagnetic switch; The control device outputs a signal to the outside when the cumulative number of switching times becomes equal to or greater than a corrected electric switch durability number obtained by correcting the electric switch durability number of the electromagnetic switch based on the inrush current of the motor and the rated current of the electromagnetic switch.

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