Motor direct current resistance automatic measurement system

Abstract

The utility model discloses an automatic measuring system for direct current resistance of a motor. The system comprises a power supply, a measured motor, a measuring device and a control device, the measuring device is connected in parallel with a line between the power supply and the measured motor; the control device is connected with the measuring device; the measuring device is used for measuring the resistance of the measured motor and sending the resistance to the control device; the control device is used for receiving the resistor and carrying out data processing on the resistor; according to the system, the measuring device is connected with the power supply and the tested motor to measure the thermal-state direct-current resistance generated by the tested motor during working, so that the direct-current resistance of the motor is effectively and automatically measured, errors are reduced, the test efficiency is improved, and meanwhile, the labor cost is reduced.

Description

Technical Field

[0001] The utility model relates to the technical field of motor testing, in particular to an automatic measurement system for direct current resistance of a motor. Background Art

[0002] The motor DC resistance measurement test can be used to check whether the motor's three-phase winding is balanced, whether the welding at the winding wire connection is good, and whether the wire specifications and resistivity meet the requirements. In addition, it is also the core parameter of the temperature rise test and loss calculation in the motor performance assessment, which has an important impact on the accuracy of the calculation results. Therefore, it is of great significance to accurately measure the motor DC resistance. At present, the test station mainly uses the QJ84A double-arm bridge to measure the motor DC resistance. This bridge measurement method has high accuracy for terminal resistance measurements below 1Ω, and the instrument is simple to operate, easy to use, and has low requirements for test personnel. Therefore, it has also been widely used. However, this traditional measurement method has a low degree of automation and a high risk of human error. When measuring hot resistance, the synchronization between the measurement result and the timer is poor. These problems can easily cause the measurement results to fail to meet the national standards, resulting in test failure and retry.

[0003] The existing DC resistance method adopts a multi-person cooperation method. After thermal stabilization, the control room communicates with the on-site operator and agrees on a countdown before braking and energy cut-off. One person keeps the time, and one person connects the instrument to the motor terminal to start measuring and record the data. When an external cooling medium is used, another person is required to cut off the cooling medium. However, this method has a low degree of automation and a high risk of human error. When measuring hot resistance, the synchronization between the measurement result and the timer is poor. When multiple people cooperate, one person makes a mistake, resulting in the failure of the test and the need to repeat the test. The stability of the test success is poor. Moreover, after the test data is processed, the technician needs to manually calculate the temperature rise result, and the test efficiency and data processing efficiency are low.

[0004] In view of this, it is a technical problem that needs to be solved urgently by those skilled in the art to provide a motor DC resistance automatic measurement system and method with a high degree of automation and improved test efficiency. Utility Model Content

[0005] The purpose of the utility model is to provide a motor DC resistance automatic measurement system and method, which can effectively realize automatic measurement of the hot DC resistance of the motor, reduce errors and thus improve test efficiency, while reducing labor costs.

[0006] In order to solve the above technical problems, the technical solutions provided by the utility model are as follows:

[0007] An automatic measurement system for direct current resistance of a motor, comprising: a power supply, a motor to be measured, a measuring device and a control device;

[0008] The measuring device is connected in parallel with the circuit between the power supply and the motor under test;

[0009] The control device is connected to the measuring device;

[0010] The measuring device is used to measure the resistance of the motor under test and send the resistance to the control device;

[0011] The control device is used to receive the resistor and perform data processing on the resistor.

[0012] Preferably, the measuring device comprises: a resistance measurer, a high-voltage vacuum contactor, a high-voltage mutual inductor, a relay and a PLC controller;

[0013] The resistance measuring device is connected to the high-voltage vacuum contactor and the PLC controller respectively, and is connected to the motor under test through the high-voltage vacuum contactor;

[0014] The high voltage transformer is connected to the relay;

[0015] The relay is connected to the PLC controller.

[0016] Preferably, the measuring device further comprises: a temperature sensor and a temperature collector;

[0017] The temperature collector is connected to the temperature sensor, and the temperature collector is connected to the PLC controller.

[0018] Preferably, the control device comprises: an industrial computer;

[0019] The industrial computer is connected to the PLC controller.

[0020] Preferably, the resistance measurer is a microohmmeter.

[0021] The utility model provides an automatic measurement system for direct current resistance of a motor, comprising: a power supply, a motor to be measured, a measuring device and a control device; the measuring device is connected in parallel with a line between the power supply and the motor to be measured; the control device is connected with the measuring device; the measuring device is used to measure the resistance of the motor to be measured and send the resistance to the control device; the control device is used to receive the resistance and perform data processing on the resistance; the system measures the direct current resistance generated by the motor to be measured when working by arranging the measuring device to be connected with the power supply and the motor to be measured, thereby effectively realizing automatic measurement of the hot direct current resistance of the motor, reducing errors and thus improving test efficiency, while reducing labor costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the embodiments of the utility model or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in the utility model. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0023] Figure 1 This is a schematic diagram of the structure of a motor DC resistance automatic measurement system in an embodiment of the utility model;

[0024] Figure 2 It is a schematic diagram of the structure of the measuring device in the embodiment of the utility model. DETAILED DESCRIPTION

[0025] In order to enable those skilled in the art to better understand the technical solutions in the utility model, the technical solutions in the embodiments of the utility model are described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments of the utility model, all other embodiments obtained by ordinary technicians in the field without creative work are within the scope of protection of the utility model.

[0026] like Figure 1 As shown, the embodiment of the utility model provides a motor DC resistance automatic measurement system, including: a power supply, a motor to be measured, a measuring device and a control device;

[0027] The measuring device is connected in parallel with the circuit between the power supply and the motor under test;

[0028] The control device is connected to the measuring device;

[0029] The measuring device is used to measure the resistance of the motor under test and send the resistance to the control device;

[0030] The control device is used to receive the resistor and perform data processing on the resistor.

[0031] In actual use, a power supply that provides electrical energy to the entire system is connected in series with the motor under test to form a main electrical circuit, and then a measuring device is connected in parallel to the main electrical circuit, wherein the motor is a three-phase winding motor, and a control device is also provided to connect with the measuring device; the hot DC resistance of one of the UV phase winding, UW phase winding and VW phase winding of the motor under test is measured by the measuring device, wherein the hot DC resistance refers to the DC resistance measured in the shortest time after the motor is powered off after it has stably run to thermal stability under specified load conditions; thereby effectively realizing the automated measurement of the hot DC resistance of the motor, reducing errors and thus improving test efficiency, while reducing labor costs; it should be noted that this system can not only measure the hot DC resistance after the thermal test, but also measure the DC resistance after other power transmission test items, such as no-load (characteristic) test, locked-rotor (characteristic) test, etc.

[0032] like Figure 2 As shown, preferably, the measuring device comprises: a resistance measuring device, a high-voltage vacuum contactor, a high-voltage mutual inductor, a relay and a PLC controller;

[0033] The resistance measuring device is connected to the high-voltage vacuum contactor and the PLC controller respectively, and is connected to the motor under test through the high-voltage vacuum contactor;

[0034] The high voltage transformer is connected to the relay;

[0035] The relay is connected to the PLC controller.

[0036] In actual use, one end of the resistance measuring device is connected to one of the UV phase winding, UW phase winding and VW phase winding of the motor under test through a high-voltage vacuum contactor to measure the hot DC resistance of one of the windings; the other end of the resistance measuring device is connected to the PLC controller to receive the hot DC resistance measured by the resistance measuring device and transmit it; one end of the high-voltage transformer is connected to the PLC controller through relay K2, and the other end of the high-voltage transformer is connected to the main power circuit through relay K1;

[0037] Specifically, when the main power circuit starts to supply power, the high-voltage transformer is in a closed state, the measuring circuit in the measuring device is disconnected, and strict physical isolation is used to eliminate the influence of the high-voltage power supply. At the same time, the four-terminal method is used to eliminate the contact resistance caused by the isolation method of the high-voltage vacuum contactor, so that it should not affect the accuracy of the measurement results; when the thermal test is completed, when the resistance meter measures the hot DC resistance, after the main power circuit is disconnected, when the control device receives the high-voltage signal collected by the high-voltage transformer on the main power circuit as 0, the control closes the measuring circuit in the measuring device, the high-voltage transformer is in a disconnected state, and starts to measure the hot DC resistance; the measuring device uploads the hot DC resistance and temperature data to the control device through the Ethernet through the PLC controller. After the measurement is completed, the control device controls the relay to disconnect, then the measuring circuit is disconnected, and the control device is based on the commonly used The resistance test formula is used to calculate the temperature rise test result of the motor; the measurement circuit in this embodiment is composed of a resistance meter, a high-voltage vacuum contactor, a high-voltage mutual inductor and a relay; the resistance meter used in this system is a precise micro-ohmmeter, which can measure resistance in the range of 0-100kΩ; it is mainly used to measure the wire resistance of cables, the contact resistance of switches, connectors, relays, the resistance of coils, motors, transformer windings and metal riveting resistance; other devices for measuring resistance can also be used according to actual conditions; the high-voltage vacuum contactor used is a switching function device used in high-voltage environments, and is often used for the control and protection of high-voltage motors; the high-voltage mutual inductor used is a mutual inductor suitable for converting high voltage into low voltage or high current into low current in 0.1 to 10kV power systems for easy measurement, protection and use.

[0038] Preferably, the measuring device further comprises: a temperature sensor and a temperature collector;

[0039] The temperature collector is connected to the temperature sensor, and the temperature collector is connected to the PLC controller.

[0040] In actual application, the measuring device also includes a temperature sensor and a temperature collector; the temperature collector is connected to the temperature sensor, and the temperature collector is connected to the PLC controller; the collected ambient temperature signal is sent to the temperature collector through the set temperature sensor, the temperature collector converts the ambient temperature signal into a digital signal, and then transmits the digital signal to the PLC controller for processing and recording; the present embodiment adopts a PT100 temperature sensor, which is an instrument that converts a temperature variable into a transmittable standardized output signal; the temperature collector used is an electronic device for measuring and recording ambient temperature, and can be any temperature collector in the field.

[0041] Preferably, the control device comprises: an industrial computer;

[0042] The industrial computer is connected to the PLC controller.

[0043] In actual application, the control device used is an industrial computer, which integrates the control system, data acquisition and analysis system, and uses a network cable to transmit the data collected by the measuring device to the industrial computer. The control system of the industrial computer controls the cutting in and out of the measuring loop, and the data acquisition and data processing software of the industrial computer receives and post-processes the data transmitted by the measuring device.

[0044] It should be noted that when an element is referred to as being "fixed on" or "set on" another element, it can be directly on the other element or indirectly set on the other element; when an element is referred to as being "connected to" another element, it can be directly connected to the other element or indirectly connected to the other element.

[0045] It should be understood that the terms "length", "width", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0046] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of the present utility model, "multiple" and "several" mean two or more, unless otherwise clearly and specifically defined.

[0047] It should be noted that the structures, proportions, sizes, etc. illustrated in the drawings of this specification are only used to match the contents disclosed in the specification so that people familiar with this technology can understand and read them. They are not used to limit the conditions under which the present utility model can be implemented, so they have no substantive technical significance. Any structural modification, change in proportional relationship or adjustment of size should still fall within the scope of the technical content disclosed by the present utility model without affecting the effects and purposes that can be achieved by the present utility model.

[0048] The above description of the disclosed embodiments enables those skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but will conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A motor DC resistance automatic measurement system, characterized in that: include: Power supply, motor under test, measuring device and control device; The measuring device is connected in parallel with the circuit between the power supply and the motor under test; The control device is connected to the measuring device; The measuring device is used to measure the resistance of the motor under test and send the resistance to the control device; The control device is used to receive the resistor and perform data processing on the resistor.

2. The motor DC resistance automatic measurement system according to claim 1, characterized in that: The measuring device comprises: a resistance measuring device, a high-voltage vacuum contactor, a high-voltage mutual inductor, a relay and a PLC controller; The resistance measuring device is connected to the high-voltage vacuum contactor and the PLC controller respectively, and is connected to the motor under test through the high-voltage vacuum contactor; The high voltage transformer is connected to the relay; The relay is connected to the PLC controller.

3. The motor DC resistance automatic measurement system according to claim 2, characterized in that: The measuring device also includes: a temperature sensor and a temperature collector; The temperature collector is connected to the temperature sensor, and the temperature collector is connected to the PLC controller.

4. The motor DC resistance automatic measurement system according to claim 2, characterized in that: The resistance measuring device is a microohm meter.

5. The motor DC resistance automatic measurement system according to claim 2, characterized in that: The control device comprises: an industrial computer; The industrial computer is connected to the PLC controller.

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