Motor winding temperature rise test device based on resistance method

Abstract

The present invention relates to a motor winding temperature rise test device based on a resistance method, comprising a switch, a contactor KM1, a contactor KM2, a resistance measuring instrument F1, a resistance measuring instrument F2 and three wiring terminals XT1, XT2 and XT3; each contactor is provided with at least two normally open contacts and two normally closed contacts, and the normally open contacts and the normally closed contacts are interlocked; the wiring terminals XT2 and XT3 are respectively connected to the two ends of the resistance measuring instrument F2 through two of the normally closed contacts of the contactor, and the wiring terminals XT1 and XT2 are respectively connected to the two ends of the resistance measuring instrument F1 through the other two normally closed contacts of the contactor on the one hand, and are also respectively powered out through two of the normally open contacts of the contactor on the other hand; the switch is used to switch the power-on state / power-off state of the control coils of all contactors. The present invention can realize that one person can complete the test independently, and both cold and hot winding resistance tests can be completed quickly, and can be applied to a variety of loads that need to test the temperature rise of the winding.

Description

Technical Field

[0001] The invention relates to a motor performance test, and in particular to a motor winding temperature rise test device based on a resistance method. Background Art

[0002] For motors, winding temperature rise is one of the important indicators for evaluating their performance. In each application, the motor needs to be tested for temperature rise when applied to the corresponding whole machine load. The resistance method is a commonly used method for testing motor winding temperature rise. The specific test steps are as follows:

[0003] 1) According to the test requirements of each model, fix the motor to the whole machine load to be applied;

[0004] 2) Move the whole machine load to the test site, wait for 120 minutes, and after the motor state is stable, use the thermometer to record the ambient temperature t1 at the beginning of the test. Generally, 25°C is recommended;

[0005] 3) Conduct cold winding resistance test: Use a multimeter to test the cold resistance of the motor winding at the beginning of the test (here, take a single-phase single-speed asynchronous motor as an example. First, test the cold resistance R1 and R1' of the main winding and the auxiliary winding. The usual test method is to manually test the two-phase winding resistance of the motor one by one using the resistance range of the multimeter);

[0006] 4) Prepare the test power supply, power on and let the motor run continuously for 4 hours (manual timing). After the temperature rise of the motor winding coil stabilizes, use the thermometer to record the ambient temperature t2 at the end of the test;

[0007] 5) Conduct hot winding resistance test: Cut off the power supply. In order to quickly and accurately obtain the temperature rise data at this time, generally use flexible devices (such as foam or wood) to quickly stop the motor from the running state, and then use a multimeter to manually test the hot resistance R2 and R2' of the main winding and auxiliary winding of the motor one by one when the motor stops;

[0008] 6) According to the following formula, calculate the temperature rise values ​​△t and △t' of the main winding and the secondary winding. For example, taking the copper enameled wire commonly used in motor windings as an example, the corresponding resistance method temperature rise test formula is:

[0009]

[0010] In the formula, △t is the winding temperature rise; R1 is the resistance at the beginning of the test; R2 is the resistance at the end of the test; t1 is the temperature at the beginning of the test; t2 is the temperature at the end of the test; 234.5 is the copper winding coefficient.

[0011] The defects of the above method are:

[0012] It is necessary to manually use a multimeter to test the resistance of each winding of the motor in the cold and hot states. Because the test process involves different types of motors, such as single-phase motors need to test the main winding and auxiliary winding separately, and three-phase motors need to test the three-phase winding separately. This process involves powering on, powering off, manually preventing the motor from stopping, reading the resistance values ​​of different windings, etc. Therefore, one person often cannot complete the temperature rise test alone. At this time, it is particularly urgent to design test tooling. Summary of the invention

[0013] The present invention aims to improve the deficiencies of the prior art and provides a motor winding temperature rise test device based on a resistance method.

[0014] To achieve the above object, the present invention is implemented by the following technical solutions:

[0015] Provide a motor winding temperature rise test device based on the resistance method.

[0016] It includes a switch, a contactor KM1, a contactor KM2, a resistance measuring instrument F1, a resistance measuring instrument F2 and three wiring terminals XT1, XT2 and XT3;

[0017] Each contactor is provided with at least two normally open contacts and two normally closed contacts, and the normally open contacts and the normally closed contacts are interlocked;

[0018] The wiring terminals XT2 and XT3 are connected to the two ends of the resistance measuring instrument F2 through two normally closed contacts of the contactor, and the wiring terminals XT1 and XT2 are connected to the two ends of the resistance measuring instrument F1 through the other two normally closed contacts of the contactor, and are also powered through two normally open contacts of the contactor.

[0019] The switch is used to switch the energized state / de-energized state of the control coils of all contactors.

[0020] Furthermore, it also includes a timing instrument, which is triggered by the action of the switch, and switches the control coils of all contactors to a powered state, and switches the control coils of all contactors to a de-powered state after a set time.

[0021] Furthermore, the timing instrument is specifically a time relay, and the switch is used to control the energized state / de-energized state of the control coil of the time relay. The time relay is provided with a normally open contact to supply power to the control coils of all contactors.

[0022] Furthermore, the switch has a plurality of conduction channels, and after the connection terminals XT1 and XT2 are each connected in series with a normally open contact, each uses a conduction channel to draw power from the outside.

[0023] Furthermore, it also includes a contactor KM3 and a resistance measuring instrument F3. The wiring terminals XT1 and XT3 are respectively connected to the two ends of the resistance measuring instrument F3 via two normally closed contacts not used in the contactor, and the wiring terminal XT3 draws power externally via another normally open contact of the contactor.

[0024] Furthermore, the switch has a plurality of conduction channels, and after the connection terminals XT1, XT2, and XT3 are each connected in series with a normally open contact, each terminal uses a conduction channel to draw power from the outside.

[0025] Furthermore, the switch has at least one unused conduction channel for externally connecting to the N line.

[0026] Furthermore, the switch is specifically a circuit breaker.

[0027] Furthermore, the resistance measuring instrument is specifically a multimeter.

[0028] Beneficial effects:

[0029] The motor winding temperature rise test device of the present invention can enable one person to complete the test independently, and both cold and hot winding resistance tests can be completed quickly. In addition, the motor winding temperature rise test device can be reused and can be applicable to a variety of loads that require winding temperature rise testing.

[0030] The above description is only an overview of the technical solution of the present invention. In order to more clearly understand the technical means of the present invention, it can be implemented according to the contents of the specification. In order to make the above and other purposes, features and advantages of the present invention more obvious and easy to understand, the specific implementation methods of the present invention are listed below. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Various other advantages and benefits will become apparent to those of ordinary skill in the art by reading the detailed description of the preferred embodiments below. The accompanying drawings are only for the purpose of illustrating the preferred embodiments and are not to be considered as limiting the present invention. Moreover, the same reference symbols are used throughout the accompanying drawings to represent the same components. In the accompanying drawings:

[0032] Figure 1 It is a circuit diagram when the test device of the present invention is applied to a single-phase load test;

[0033] Figure 2 It is a circuit diagram of the test device of the present invention when applied to three-phase load testing. DETAILED DESCRIPTION

[0034] The exemplary embodiments of the present disclosure will be described in more detail below with reference to the accompanying drawings. Although the exemplary embodiments of the present disclosure are shown in the accompanying drawings, it should be understood that the present disclosure can be implemented in various forms and should not be limited by the embodiments set forth herein. On the contrary, these embodiments are provided to enable a more thorough understanding of the present disclosure and to fully convey the scope of the present disclosure to those skilled in the art.

[0035] Example 1

[0036] See Figure 1 The test device of this embodiment is applied to single-phase load test, and mainly includes:

[0037] (1) Circuit breaker QF1, its selection requirements are: the number of poles is selected as 2 poles according to the needs, and the rated current is selected according to the load;

[0038] (2) Time relay KT1, its selection requirements are: the timing time can be set as needed, with at least one set of normally open contacts, and the rated voltage and current of the contacts meet the working requirements of the matching AC contactor;

[0039] (3) AC contactors KM1 and KM2, the selection requirements are: with 2 normally open contacts and 2 normally closed contacts, the normally open contacts and the normally closed contacts are interlocked, and the rated voltage and current of the contacts meet the test load requirements;

[0040] (4) Conventional multimeter F1, F2, and terminal blocks XT1, XT2, and XT3.

[0041] In the test device, the wiring terminals XT2 and XT3 are connected to the two ends of the multimeter F2 via the two normally closed contacts (5 / 6 and 7 / 8) of the AC contactor KM2 respectively. The wiring terminals XT1 and XT2 are connected to the two ends of the multimeter F1 via the two normally closed contacts (5 / 6 and 7 / 8) of the AC contactor KM1 respectively, and are connected to the circuit breaker QF1 via the two normally open contacts (1 / 2 and 3 / 4) of the AC contactor KM1 respectively on the other hand, and power is taken to the outside through the circuit breaker QF1.

[0042] Among them, two lines between the two normally open contacts of the AC contactor KM1 and the circuit breaker QF1 supply power to the control coil (A1 and A2) of the time relay KT1, and a group of normally open contacts (15 and 18) of the time relay KT1 supplies power to the control coils (A1 and A2) of the AC contactors KM1 and KM2.

[0043] The test device of this embodiment is used as follows:

[0044] (1) Figure 1After the preparation of the whole machine load (Load) with the motor is completed, the wiring is completed according to the dotted line on the right. After the whole machine load is placed in the test site for a specified time, the cold resistance values ​​of the main winding (brown + black) and the secondary winding (red + black) of the motor are directly read through the multimeters F1 and F2, and the ambient temperature t1 at this time is recorded. In this process, since the circuit breaker QF1 has not been closed, the normally closed contacts of the AC contactors KM1 and KM2 are always in the closed state, so the multimeters F1 and F2 are automatically connected to the connection position without manual operation;

[0045] (2) According to the test requirements, set the timing time of time relay KT1;

[0046] (3) Connect the test power supply to the whole load by closing the circuit breaker QF1, so that the load is powered on and the test starts. At this time, the control coil (A1 and A2) of the time relay KT1 is energized, and the time relay KT1 starts timing. Its normally open contacts (15 and 18) are changed from normally open to normally closed, so that the control coils (A1 and A2) of KM1 and KM2 are energized, and the normally open contacts (1 / 2 and 3 / 4) of KM1 and KM2 are changed from normally open to closed, and the motor is powered on. At the same time, the normally closed contacts (5 / 6 and 7 / 8) of KM1 and KM2 are changed from normally closed to open, automatically cutting off the connection between the multimeters F1 and F2 and the motor windings, and stopping the cold resistance test;

[0047] (4) When the working time of KT1 reaches the set timing time, its normally open contacts (15 and 18) are changed from normally closed to normally open. At this time, the control coils (A1 and A2) of KM1 and KM2 are cut off from power, the normally open contacts (1 / 2 and 3 / 4) of KM1 and KM2 are disconnected, and the motor stops working due to power loss. At the same time, the normally closed contacts (5 / 6 and 7 / 8) of KM1 and KM2 are closed, and the multimeters F1 and F2 are connected. At this time, the motor is quickly stopped from the running state by artificial flexible devices. The hot resistance values ​​of the main winding (brown + black) and the auxiliary winding (red + black) can be directly read at once through the multimeters F1 and F2, and the ambient temperature t2 at this time is recorded;

[0048] (5) The temperature rise value of the motor is calculated using the formula mentioned in the background technology.

[0049] The advantages of the test device of this embodiment are:

[0050] (1) There is a circuit breaker at the power input end. In case of a short circuit caused by a wiring error, the circuit breaker will trip in time to prevent danger;

[0051] (2) It is implemented by pure electrical circuits, does not require software and hardware design, has simple components, is low cost, and can quickly build a test platform;

[0052] (3) Once the test tooling is completed, the test can be completed independently by one person, and both cold and hot winding resistance tests can be completed quickly;

[0053] (4) The test fixture is reusable and can be designed once and applied to a variety of loads that need to test the temperature rise of the winding using the same solution.

[0054] It should be noted that, in this embodiment, the time relay KT1 can be replaced by other timing instruments, such as a controller to time and control the control coils of KM1 and KM2, the multimeters F1 and F2 can be replaced by other resistance measuring instruments, and the circuit breaker QF1 can be replaced by other switches.

[0055] Furthermore, a display screen can be provided to display the detection values ​​of each multimeter (such as resistance value), the detection values ​​of the current test environment (such as temperature, humidity) during the test, and the test results (such as motor winding temperature rise) when the test is completed.

[0056] Example 2

[0057] See Figure 2 , Example 2 is based on Example 1, with the addition of AC contactor KM3 and multimeter F3, and the circuit breaker QF1 is selected as a 4-pole circuit breaker, then the circuit becomes:

[0058] The wiring terminals XT1 and XT3 are connected to the two ends of the multimeter F3 via the two normally closed contacts (5 / 6 and 7 / 8) of the AC contactor KM3, and the wiring terminals XT2 and XT3 are connected to the two ends of the multimeter F2 via the two normally closed contacts (5 / 6 and 7 / 8) of the AC contactor KM2. On the one hand, the wiring terminals XT1 and XT2 are connected to the two ends of the multimeter F1 via the two normally closed contacts (5 / 6 and 7 / 8) of the AC contactor KM1, and on the other hand, they are connected to the L1 and L2 poles of the circuit breaker QF1 via the two normally open contacts (1 / 2 and 3 / 4) of the AC contactor KM1, and the L3 pole of the circuit breaker QF1 is connected to the wiring terminal XT3 via one of the normally open contacts (1 / 2) of the AC contactor KM3.

[0059] The control coil (A1 and A2) of the time relay KT1 is powered by one of the poles of the phase power and the N pole of the circuit breaker QF1. A set of normally open contacts (15 and 18) of the time relay KT1 supplies power to the control coils (A1 and A2) of the AC contactors KM1, KM2, and KM3.

[0060] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit the scope of protection of the present invention. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solution of the present invention can be modified or replaced by equivalents without departing from the essence and scope of the technical solution of the present invention.

Claims

1. A motor winding temperature rise test device based on the resistance method, characterized in that: It includes a switch, a contactor KM1, a contactor KM2, a resistance measuring instrument F1, a resistance measuring instrument F2 and three wiring terminals XT1, XT2 and XT3; Each contactor is provided with at least two normally open contacts and two normally closed contacts, and the normally open contacts and the normally closed contacts are interlocked; The wiring terminals XT2 and XT3 are connected to the two ends of the resistance measuring instrument F2 through two normally closed contacts of the contactor, and the wiring terminals XT1 and XT2 are connected to the two ends of the resistance measuring instrument F1 through the other two normally closed contacts of the contactor, and are also powered through two normally open contacts of the contactor. The switch is used to switch the energized state / de-energized state of the control coils of all contactors; It also includes a timing instrument, which is triggered by the action of the switch, and switches the control coils of all contactors to a powered state, and switches the control coils of all contactors to a de-powered state after a set time. The timing instrument is specifically a time relay, and the switch is used to control the powered state / de-powered state of the control coil of the time relay. The time relay is provided with a normally open contact to supply power to the control coils of all contactors; The resistance measuring instrument is specifically a multimeter.

2. The motor winding temperature rise test device according to claim 1, characterized in that: The switch has a plurality of conduction channels. After the connection terminals XT1 and XT2 are connected in series with normally open contacts, each terminal uses a conduction channel to draw power from the outside.

3. The motor winding temperature rise test device according to claim 2, characterized in that: The switch is specifically a circuit breaker.

4. The motor winding temperature rise test device according to claim 1, characterized in that: It also includes a contactor KM3 and a resistance measuring instrument F3. The wiring terminals XT1 and XT3 are respectively connected to the two ends of the resistance measuring instrument F3 via two normally closed contacts not used in the contactor, and the wiring terminal XT3 draws power externally via another normally open contact of the contactor.

5. The motor winding temperature rise test device according to claim 4, characterized in that: The switch has a plurality of conduction channels. After the connection terminals XT1, XT2, and XT3 are connected in series with normally open contacts, each terminal uses a conduction channel to draw power from the outside.

6. The motor winding temperature rise test device according to claim 5, characterized in that: The switch at least leaves an unused conduction channel to be externally connected to an N line.

7. The motor winding temperature rise test device according to claim 6, characterized in that: The switch is specifically a circuit breaker.

Images