Anti-burnout protection circuit for frequent starting of motor

Abstract

The utility model discloses a motor frequent start anti-burnout protection circuit, which comprises a main loop and a master control loop, the master control loop comprises a contactor KM starting loop and an intermediate relay KA coil loop which are connected in parallel, and the master control loop is connected with a circuit breaker QF1 in series. The utility model has the advantages that the device can timely and effectively remind an operator when to restart the motor, so as to avoid burnout caused by starting the motor when the motor is not completely cooled, and effectively prolong the service life of the motor.

Description

Technical field:

[0001] The utility model relates to the technical field of motor control, in particular to a motor frequent starting anti-burning protection circuit. Background technology:

[0002] Motor restart is usually divided into cold start and hot start. Cold start means that the winding temperature has reached the natural temperature when the motor starts, while hot start means that the temperature of the motor before starting is higher than the natural temperature.

[0003] During use, only by waiting for the motor to cool down completely before restarting can the service life of the motor be effectively extended and the motor burning caused by frequent restarting before the motor is completely cooled can be avoided. However, in actual operation, operators often ignore the above situation during the restart process, especially for new employees. Restarting the motor without waiting for the motor to cool down completely often causes the motor to burn out due to the short starting time interval, seriously affecting normal production. Utility model content:

[0004] The utility model aims to provide a motor frequent starting anti-burning protection circuit which is beneficial to prolonging the service life of the motor.

[0005] The utility model is implemented by the following technical scheme: a motor frequent starting anti-burning protection circuit, which includes a main circuit and a total control circuit, the total control circuit includes a contactor KM starting circuit and an intermediate relay KA coil circuit connected in parallel, and a circuit breaker QF1 is connected in series to the total control circuit;

[0006] The normally closed auxiliary contacts of the contactor KM connected in series and the motor start permission indicator light HL1 are connected in parallel with the normally open auxiliary contacts of the contactor KM connected in series and the contactor KM coil, and then connected in series with the normally closed switch SB1 and the normally closed auxiliary contacts of the intermediate relay KA to form the contactor KM start circuit. The normally open auxiliary contacts of the contactor KM are connected in parallel with the normally open switch SB2.

[0007] The coil circuit of the intermediate relay KA includes a normally open switch SB1, a power-on delayed disconnection contact of the time relay KT, and a coil of the intermediate relay KA connected in series. The normally closed switch SB1 is interlocked with the normally open switch SB1. The normally open auxiliary contact of the intermediate relay KA is connected in parallel to the normally open switch SB1. The power-on delayed disconnection contact of the time relay KT and the coil of the intermediate relay KA connected in series are connected in parallel with the coil of the time relay KT and the motor starting not allowed indicator light HL2.

[0008] Furthermore, the main circuit includes a control switch QF connected in series with the three-phase winding of the motor M, a normally open main contact of the contactor KM and a coil of a thermal relay FR.

[0009] Furthermore, the normally closed auxiliary contact of the thermal relay FR is connected in series to the contactor KM coil on the contactor KM starting circuit.

[0010] The utility model has the advantages that the utility model can timely and effectively remind the operator when to restart the motor, thus avoiding the burning of the motor caused by starting the motor before it is completely cooled, and effectively prolonging the service life of the motor. Description of the drawings:

[0011] Figure 1 It is a schematic diagram of the control circuit of the utility model.

[0012] Figure 2 It is a schematic diagram of the main circuit of the utility model.

[0013] The components in the attached drawings are marked as follows: main circuit 1, total control circuit 2, contactor KM starting circuit 3, intermediate relay KA coil circuit 4. Specific implementation method:

[0014] The following will be combined with the drawings in the embodiments of the utility model to clearly and completely describe the technical solutions in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments in the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0015] like Figure 1 and Figure 2 As shown, this embodiment provides a motor frequent starting anti-burning protection circuit, which includes a main circuit 1 and a total control circuit 2. The main circuit 1 includes a control switch QF connected in series with the three-phase winding of the motor M, a normally open main contact of the contactor KM and a thermal relay FR coil.

[0016] The total control circuit 2 includes a parallel contactor KM starting circuit 3 and an intermediate relay KA coil circuit 4. A circuit breaker QF1 is connected in series to the total control circuit 2. The normally closed auxiliary contacts of the contactor KM and the motor start permission indicator light HL1 connected in series are connected in parallel with the normally open auxiliary contacts of the contactor KM and the contactor KM coil connected in series, and then connected in series with the normally closed switch SB1 and the normally closed auxiliary contacts of the intermediate relay KA to form a contactor KM starting circuit 3. The contactor KM coil on the contactor KM starting circuit 3 is connected in series with the normally closed auxiliary contacts of the thermal relay FR, which plays an effective protection role. Use; the normally open switch SB2 is connected in parallel to the normally open auxiliary contact of the contactor KM; when the motor M is in normal operating state, the control switch QF and the circuit breaker QF1 are in the closed state, the coil of the contactor KM is in the energized state, the normally open auxiliary contacts of the contactor KM are closed and self-locked, the normally closed auxiliary contacts of the contactor KM are in the disconnected state, and the motor start-allowed indicator light HL1 is in the off state; when the motor M needs to be stopped, the normally closed switch SB1 is disconnected, the coil of the contactor KM loses power, the normally open main contacts of the contactor KM are disconnected, and at the same time, the normally closed auxiliary contacts of the contactor KM are closed.

[0017] The coil circuit 4 of the intermediate relay KA includes a normally open switch SB1, a power-on delayed disconnection contact of the time relay KT, and a coil of the intermediate relay KA in series. The normally closed switch SB1 is interlocked with the normally open switch SB1. The normally open auxiliary contact of the intermediate relay KA is connected in parallel to the normally open switch SB1. The power-on delayed disconnection contact of the time relay KT and the coil of the intermediate relay KA in series are connected in parallel to the coil of the time relay KT and the motor not allowed to start indicator HL2. When the normally closed switch SB1 is disconnected, the normally open switch SB1 is interlocked and closed, the coil of the intermediate relay KA is energized, the normally closed auxiliary contact of the intermediate relay KA is disconnected, the normally open auxiliary contact of the intermediate relay KA is closed and self-locked, the coil of the time relay KT is energized, and timing starts. At the same time, the motor not allowed to start indicator HL2 lights up to remind the operator Personnel are not allowed to start the motor M at this time, which is in a cooling state; when the time set by the time relay KT is reached, the coil of the time relay KT loses power, the power-on delay disconnection contact of the time relay KT is disconnected, the coil of the intermediate relay KA loses power, the normally open auxiliary contacts of the intermediate relay KA are disconnected, the motor is not allowed to start indicator HL2 goes out, the normally closed auxiliary contacts of the intermediate relay KA are closed, and the motor is allowed to start indicator HL1 lights up, reminding the operator that the motor M can be started. At this time, the operator presses the normally open switch SB2, the coil of the contactor KM is energized, the normally open main contacts of the contactor KM are closed, and the motor M starts; therefore, the utility model can timely and effectively remind the operator when to restart the motor, avoid starting the motor before it is completely cooled and causing burning, and effectively extend the service life of the motor.

[0018] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A motor frequent starting anti-burning protection circuit, which includes a main circuit and a total control circuit, characterized in that: The total control circuit includes a contactor KM start circuit and an intermediate relay KA coil circuit connected in parallel, and a circuit breaker QF1 is connected in series to the total control circuit; The normally closed auxiliary contacts of the contactor KM connected in series and the motor start permission indicator light HL1 are connected in parallel with the normally open auxiliary contacts of the contactor KM connected in series and the contactor KM coil, and then connected in series with the normally closed switch SB1 and the normally closed auxiliary contacts of the intermediate relay KA to form the contactor KM start circuit. The normally open auxiliary contacts of the contactor KM are connected in parallel with the normally open switch SB2. The coil circuit of the intermediate relay KA includes a normally open switch SB1, a power-on delayed disconnection contact of the time relay KT, and a coil of the intermediate relay KA connected in series. The normally closed switch SB1 is interlocked with the normally open switch SB1. The normally open auxiliary contact of the intermediate relay KA is connected in parallel to the normally open switch SB1. The power-on delayed disconnection contact of the time relay KT and the coil of the intermediate relay KA connected in series are connected in parallel with the coil of the time relay KT and the motor starting not allowed indicator light HL2.

2. A motor frequent start-up anti-burning protection circuit according to claim 1, characterized in that: The main circuit includes a control switch QF connected in series with the three-phase winding of the motor M, a normally open main contact of the contactor KM and a coil of a thermal relay FR.

3. A motor frequent start-up anti-burning protection circuit according to claim 1, characterized in that: The normally closed auxiliary contact of the thermal relay FR is connected in series to the contactor KM coil in the contactor KM starting circuit.

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