Canned electric motor capable of monitoring rotating speed of rotor in real time, and real-time monitoring method

Abstract

The present invention relates to the field of canned electric motor rotating speed monitoring. Disclosed are a canned electric motor capable of monitoring the rotating speed of a rotor in real time, and a real-time monitoring method. The canned electric motor comprises an electric motor body, which has an electric motor rotor and an electric motor stator, wherein a measurement base is mounted on the electric motor stator, a plurality of coils are mounted on the measurement base, and the electric motor rotor is in mechanical transmission connection with a permanent magnet; all the coils are located in a magnetic field of the permanent magnet, and the mounting positions of the coils relative to the permanent magnet meet the condition that "as the permanent magnet rotates, the magnetic flux of the coils will change"; the plurality of coils are connected in series, and the coils located at a head end and a tail end are connected to a processor; and a pressure-bearing sleeve is fixedly and hermetically assembled on the electric motor stator, and the permanent magnet and the structure thereof in mechanical transmission connection with the electric motor rotor are both located inside the pressure-bearing sleeve. By means of the present invention, the rotating speed of the rotor of the canned electric motor can be accurately monitored in real time, such that an abnormal rotating speed of the canned electric motor can be found in a timely manner, thereby preventing an accident from further deterioration.

Description

A shielded motor capable of real-time monitoring of rotor speed and a real-time monitoring method Technical Field

[0001] This invention relates to the field of shielded motor speed monitoring, and in particular to a shielded motor capable of real-time monitoring of rotor speed and a real-time monitoring method. Background Technology

[0002] Shielded motors are used to transport highly toxic, corrosive, radioactive, flammable, explosive, or valuable liquids, as well as liquids whose leakage would cause significant hazards. A shielded motor is directly connected to the pump impeller via its shaft to form a shielded pump. A shielded pump is a seal-less pump; the pump and drive motor are sealed within a pressure vessel filled with the pumped medium. This pressure vessel has only a static seal, eliminating the rotary seal found in centrifugal pumps, thus achieving complete leak-free operation. Historically, however, shielded motors have been prone to serious accidents due to the small stator-rotor clearance and significant shield wear, which can lead to shield bulging, rotor jamming, and ultimately, motor failure.

[0003] Currently, there are three main methods for measuring motor speed: excitation coil speed measurement, photoelectric digital speed measurement, and tachogenerator speed measurement. Excitation coil speed measurement works by setting two or more excitation coils on the shielded motor. An electrical signal is input to one set of excitation coils (A) when the motor is not in operation, and the output signal from another set of excitation coils (B) is detected. The signal is extracted from the output signal and then converted into the forced rotation speed of the rotor. However, its principle and structure cannot be applied to measuring the speed of shielded motors operating at high speeds. Photoelectric digital speed measurement works by converting light signals into electrical signals related to the motor speed using a speed sensor. Speed ​​sensors mainly include photoelectric encoders or gratings, both of which generate speed-related pulsed electrical signals. The speed is determined by measuring the number of pulses proportional to the speed per unit time, or by measuring the time required to generate one electrical pulse signal. However, its principle and structure cannot be applied to the high-pressure environment and various corrosive media environments of shielded motors, severely limiting its application. The principle of tachogenerator speed measurement is based on the fact that the output voltage of a DC generator is proportional to its rotational speed. A small DC generator is installed on the shaft of the motor under test, and the rotational speed of the motor is obtained simply based on the voltage output by the generator. However, this principle and structure cannot be applied to high-temperature and high-pressure shielded motors with compact structures and sealed internal shafts. Other speed measuring instruments based on principles such as leakage flux measurement and vibration measurement cannot be used to measure the rotor speed of shielded motors due to limitations in their structure or the operating environment.

[0004] In summary, due to the completely enclosed nature of shielded motors (rotating components cannot be observed from the outside), the rotor speed of shielded motors cannot be detected using normal motor speed measurement methods, ultimately leading to further deterioration of the shielded motor's malfunction. Therefore, there is a need in this field for a technical solution capable of real-time monitoring of the rotor speed of shielded motors. Summary of the Invention

[0005] The purpose of this invention is to address the aforementioned problems by providing a shielded motor and a real-time monitoring method that can monitor the rotor speed in real time. This method can accurately monitor the rotor speed of the shielded motor in real time, promptly detect abnormal speeds, and prevent further deterioration of the accident.

[0006] The technical solution adopted in this invention is as follows: A shielded motor capable of real-time monitoring of rotor speed includes a motor body, which has a motor rotor and a motor stator. The motor stator is fixed, and the motor rotor rotates relative to the motor stator. A measuring base is directly or indirectly mounted on the motor stator, and multiple coils are installed on the measuring base. The motor rotor is mechanically connected to a permanent magnet, which can obtain rotational power from the motor rotor. All coils are located within the magnetic field of the permanent magnet, and the permanent magnet rotates about the perpendicular bisector of its own north-south pole line as its axis. The plane where coil 4 is located is perpendicular to the perpendicular bisector. Multiple coils are connected in series, and the coils at the beginning and end are connected to a processor. A pressure-bearing sleeve is also fixedly and sealed on the motor stator, and the permanent magnet and its mechanically connected structure to the motor rotor are located within the pressure-bearing sleeve.

[0007] Furthermore, the permanent magnet is fixed to the measuring rod, and the measuring rod is connected to the motor rotor through a mechanical transmission connection structure.

[0008] Furthermore, the top of the measuring rod is provided with a countersunk hole, the permanent magnet is assembled in the countersunk hole, and the opening of the countersunk hole is sealed and fixedly connected with a cap.

[0009] Furthermore, the geometry and size of the countersunk hole are matched to the permanent magnet.

[0010] Furthermore, the measuring rod, as a mechanical transmission connection structure, is fixedly connected to the motor rotor along the same axis.

[0011] Furthermore, the measuring base has a mounting cavity, and the coil is fixed inside the mounting cavity; the pressure-bearing sleeve is fitted onto the measuring rod and passes through the mounting cavity, so that the permanent magnet is located inside the mounting cavity.

[0012] Furthermore, the pressure-bearing sleeve is made of a non-magnetic material.

[0013] Furthermore, the coil is connected to the processor via a frequency transmitter.

[0014] A method for real-time monitoring of the rotational speed of a shielded motor, utilizing the aforementioned shielded motor capable of real-time rotor speed monitoring, includes the following steps:

[0015] S1: The motor rotor rotates, synchronously rotating with the permanent magnet;

[0016] S2: The permanent magnet rotates, the magnetic flux of the coil changes, and a periodic induced electromotive force is generated;

[0017] S3: The frequency at which the processor acquires the induced electromotive force;

[0018] S4: The rotational speed of the motor rotor is obtained based on the frequency of the induced electromotive force.

[0019] In summary, due to the adoption of the above technical solution, the beneficial effects of the present invention are:

[0020] 1. This invention enables passive measurement of the rotational speed of a shielded motor, meaning that the rotational speed of the shielded motor can be acquired in real time without the need for an external power supply to power the measuring part. Only power needs to be supplied to the processor and / or the frequency transmitter.

[0021] 2. In this invention, the permanent magnet follows the rotor's rotation, causing a change in the magnetic flux of the coil, which in turn generates an induced electromotive force. The rotor speed is then determined based on the frequency of the induced electromotive force.

[0022] 3. This invention forms a pressure boundary by setting a pressure-bearing sleeve, which isolates the internal and external environments of the shielded motor, so that the permanent magnet and coil can be used to monitor the speed of the motor rotor of the shielded motor without being affected by high pressure, corrosion and other environmental factors. Attached Figure Description

[0023] The present invention will be described by way of example and with reference to the accompanying drawings, wherein:

[0024] Figure 1 is a schematic diagram of the structure of the present invention;

[0025] Figure 2 shows the frequency diagram of output at different speeds;

[0026] The markings in the diagram are: 1-measuring base; 11-mounting cavity; 2-permanent magnet; 3-measuring rod; 4-coil; 5-cover; 6-pressure bearing sleeve; 7-motor stator. Embodiments of the present invention

[0027] In the description of this invention, it should be noted that if terms such as "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," or "outer" are used to indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship in which the product of this invention is usually placed, they are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this invention.

[0028] Furthermore, the use of terms such as "horizontal" and "vertical" in the description of this invention does not imply that the components are required to be absolutely horizontal or suspended, but rather that they can be slightly tilted. For example, "horizontal" simply means that its direction is more horizontal than "vertical," and does not mean that the structure must be completely horizontal, but can be slightly tilted.

[0029] In the description of this invention, it should also be noted that, unless otherwise explicitly specified and limited, the terms “set,” “install,” “connect,” and “link” should be interpreted broadly. For example, a link can be a fixed link, a detachable link, or an integral link; it can be a mechanical link or an electrical link; it can be a direct link or an indirect link through an intermediate medium; or it can be a connection within two components.

[0030] Example 1

[0031] As shown in Figures 1 and 2, a shielded motor capable of real-time monitoring of rotor speed includes a motor body, which has a motor rotor and a motor stator 7. The motor stator 7 is fixed, and the motor rotor rotates relative to the motor stator 7. The assembly relationship between the motor rotor and the motor stator 7 is known to those skilled in the art and will not be described in detail in this specification.

[0032] In this embodiment, a measuring seat 1 is directly or indirectly mounted on the motor stator 7. It can be directly bolted to the motor stator 7; alternatively, the measuring seat 1 can be mounted on a base, which is bolted to the motor stator 7. Preferably, it is mounted on the motor body at the end furthest from the pump body to minimize the pump body's influence on the measurement. The motor rotor is mechanically connected to a permanent magnet 2, which obtains rotational power from the motor rotor. Specifically, the permanent magnet 2 can obtain rotational power from the motor rotor through mechanical transmission methods such as gears, coaxial cables, or chains. However, when a transmission ratio exists, it should be considered when determining the final motor speed. That is, the actual monitored speed is the speed of the permanent magnet 2. Determining the motor speed requires conversion using the transmission ratio. The conversion method is known to those skilled in the art and will not be elaborated upon in this specification.

[0033] In this embodiment, to measure the rotational speed of the permanent magnet 2 and thus obtain the rotational speed of the shielded motor rotor, at least one coil 4 can be set on the measuring base 1. All coils 4 are located within the magnetic field of the permanent magnet 2, and the installation position of the coils 4 relative to the permanent magnet 2 satisfies the condition that "as the permanent magnet 2 rotates, the magnetic flux of the coil 4 will change." That is, if the permanent magnet 2 rotates around the perpendicular bisector of its own north-south pole line as its axis, the plane where the coil 4 is located forms a certain angle with the perpendicular bisector, preferably 90°, so that the change in magnetic flux of the coil 4 is maximized, thereby maximizing the induced electromotive force of the coil 4. The coil 4 is connected to the processor, which acquires the induced electromotive force of the coil 4 and processes the data of the induced electromotive force, such as peak value, period, frequency, etc. In this embodiment, the rotational speed of the permanent magnet 2 can be obtained based on the frequency of the induced electromotive force, thereby obtaining the rotational speed of the shielded motor rotor.

[0034] In this embodiment, multiple coils 4 are connected in series, and the coils 4 at the beginning and end are connected to the processor, so that the induced electromotive force generated by each coil 4 is superimposed, thereby increasing the effective signal and improving the stability of signal acquisition.

[0035] It should be noted that when connecting each coil 4 in series with wires, the positive and negative directions of the induced electromotive force generated by the coil 4 need to be considered. This is known to those skilled in the art, and will not be described in detail in this specification.

[0036] In this embodiment, a pressure-bearing sleeve 6 is also fixedly and sealed on the motor stator, meaning that there is relative rotation between the pressure-bearing sleeve 6 and the permanent magnet 2, which will not affect the measured data. The permanent magnet 2 and its mechanical transmission connection with the motor rotor are all located inside the pressure-bearing sleeve 6, which actually isolates the internal environment of the shielded motor from the external environment. That is, the medium is located inside the pressure-bearing sleeve 6, so that the pressure-bearing sleeve 6 forms a pressure boundary to prevent the medium inside the shielded motor from leaking into the external environment.

[0037] Furthermore, the pressure sleeve 6 is made of non-magnetic material to prevent the formation of magnetic shielding and ensure the accuracy of the measured data.

[0038] In summary, the solution disclosed in this embodiment enables passive measurement of the speed of a shielded motor. That is, it allows for real-time acquisition of the motor's speed during operation without requiring an external power source to power the measurement unit; only the processor and / or frequency transmitter need to be supplied with power. By having the permanent magnet 2 rotate with the rotor, the magnetic flux of the coil 4 changes, thereby generating an induced electromotive force (EMF) in the coil 4. The rotor speed is then determined based on the frequency of this induced EMF. By setting a pressure-bearing sleeve 6 to form a pressure boundary, the internal and external environments of the shielded motor are isolated, allowing the permanent magnet 2 and coil 4 to be used for monitoring the rotor speed of the shielded motor without being affected by high pressure, corrosion, or other environmental factors.

[0039] Example 2

[0040] Based on Example 1, further feasible implementation methods are proposed.

[0041] In one feasible implementation, the permanent magnet 2 is fixed on the measuring rod 3, which can be fixedly connected to the motor rotor on the same axis. That is, the permanent magnet 2 is connected to the motor rotor through the measuring rod 3, which facilitates the installation of the permanent magnet 2 and also enables the rotation speed of the permanent magnet 2 to be synchronized with the rotation speed of the motor rotor without the need for too many conversion procedures.

[0042] Furthermore, the bottom of the measuring rod 3 is used for fixed connection with the motor rotor on the same axis, and the top of the measuring rod 3 is provided with a countersunk hole. The permanent magnet 2 is assembled in the countersunk hole, and the opening of the countersunk hole is sealed and fixedly connected with a cover 5, which effectively avoids the medium inside the motor from contaminating or corroding the permanent magnet 2.

[0043] In one feasible implementation, the size of the countersunk hole matches the size of the permanent magnet 2. With the constraint of the cover 5, the permanent magnet 2 is fixed in the countersunk hole, so that the permanent magnet 2 can be completely synchronized when rotating with the motor rotor. It will not lag in starting to rotate due to the inertia of the permanent magnet 2 itself, nor will it delay stopping to rotate.

[0044] In one feasible implementation, regarding the installation of the coil 4, a mounting cavity 11 can be opened on the measuring base 1, the coil 4 is fixed in the mounting cavity 11, the measuring rod 3 passes through the mounting cavity 11, and the permanent magnet 2 is located in the mounting cavity 11; the coil 4 is arranged in a circumferential array around the rotation axis of the measuring rod 3.

[0045] In one feasible implementation, coil 4 is connected to the processor via a frequency transmitter to transmit the frequency signal of the induced electromotive force. The processor receives the frequency signal and determines the rotational speed of the motor rotor based on the frequency signal. In this embodiment, the frequency transmitter can be an ASGFC-H1D transmitter, and the processor can be a microprocessor.

[0046] It should be noted that the frequency transmitter and microprocessor can be connected to an external power supply to ensure a continuous power supply and maintain the stability of frequency signal transmission and processing.

[0047] Example 3

[0048] A method for real-time monitoring of the rotational speed of a shielded motor, using a shielded motor capable of real-time rotor speed monitoring as described in any one of the embodiments 1-2, includes the following steps:

[0049] S1: The motor rotor rotates, causing the permanent magnet 2 to rotate synchronously;

[0050] S2: When the permanent magnet 2 rotates, the magnetic flux of the coil 4 changes, generating a periodic induced electromotive force.

[0051] S3: The frequency at which the processor acquires the induced electromotive force;

[0052] S4: The rotational speed of the motor rotor is obtained based on the frequency of the induced electromotive force.

[0053] This invention is not limited to the specific embodiments described above. The invention extends to any new feature or combination disclosed in this specification, as well as any new method or process step or combination disclosed herein.

Claims

1. A shielded motor capable of real-time monitoring of rotor speed, comprising a motor body having a motor rotor and a motor stator (7), wherein the motor stator (7) is fixed and the motor rotor rotates relative to the motor stator (7); characterized in that: A measuring seat (1) is directly or indirectly mounted on the motor stator (7), and multiple coils (4) are installed on the measuring seat (1). The motor rotor is mechanically connected to a permanent magnet (2), which can obtain rotational power from the motor rotor. All coils (4) are located in the magnetic field of the permanent magnet (2), and the permanent magnet (2) rotates about the perpendicular bisector of its own north-south pole line. The plane where the coil 4 is located is perpendicular to the perpendicular bisector. Multiple coils (4) are connected in series, and the coils (4) at the beginning and end are connected to the processor. A pressure sleeve (6) is also fixedly and sealed on the motor stator (7). The permanent magnet (2) and its mechanical transmission connection with the motor rotor are located in the pressure sleeve (6).

2. The shielded motor according to claim 1, characterized in that: The permanent magnet (2) is fixed on the measuring rod (3), and the measuring rod (3) is connected to the motor rotor through a mechanical transmission connection structure.

3. The shielded motor according to claim 2, characterized in that: The top of the measuring rod (3) is provided with a countersunk hole, the permanent magnet (2) is assembled in the countersunk hole, and the opening of the countersunk hole is sealed and fixedly connected with a cap (5).

4. The shielded motor according to claim 3, characterized in that: The geometry and size of the countersunk hole are matched to the permanent magnet.

5. The shielded motor according to claim 2, characterized in that: The measuring rod (3) serves as a mechanical transmission connection structure and is fixedly connected to the motor rotor on the same axis.

6. The shielded motor according to claim 5, characterized in that: The measuring base (1) has a mounting cavity (11), and the coil (4) is fixed inside the mounting cavity (11); the pressure sleeve (6) is fitted onto the measuring rod (3) and passes through the mounting cavity (11), so that the permanent magnet (2) is located inside the mounting cavity (11).

7. The shielded motor according to claim 6, characterized in that: The pressure sleeve (6) is made of non-magnetic material.

8. The shielded motor according to claim 1, characterized in that: The coil (4) is connected to the processor via a frequency transmitter.

9. A method for real-time monitoring of the rotational speed of a shielded motor, using the shielded motor capable of real-time monitoring of rotor speed as described in any one of claims 1-8, characterized in that: Includes the following steps: S1: The motor rotor rotates, carrying the permanent magnet (2) to rotate synchronously; S2: When the permanent magnet (2) rotates, the magnetic flux of the coil (4) changes, generating a periodic induced electromotive force; S3: The frequency at which the processor acquires the induced electromotive force; S4: The rotational speed of the motor rotor is obtained based on the frequency of the induced electromotive force.

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