How to connect the auto-coupling step-down starting control cabinet

The auto-coupling step-down starting control cabinet is a commonly used motor starting device. It uses an autotransformer to reduce the starting voltage of the motor, thereby reducing the starting current and protecting the motor and the power grid. This article will introduce the wiring method of the auto-coupling step-down starting control cabinet in detail, including the wiring of the main circuit, control circuit and protection circuit.

1. Main circuit wiring

The main circuit of the auto-coupling step-down starting control cabinet mainly includes auto-coupling transformer, contactor, motor and other components. The wiring steps are as follows:

1.1 Determine the rated voltage and power of the motor and select a suitable autotransformer. The rated voltage of the autotransformer should be the same as the rated voltage of the motor, and the rated capacity should be greater than the power of the motor.

1.2 Connect the high voltage side of the autotransformer to the power supply and the low voltage side to the motor. The specific wiring method is as follows:

• Connect the three-phase wires of the power supply to the three input terminals on the high-voltage side of the autotransformer respectively.

• Connect the three output terminals on the low-voltage side of the autotransformer to the three wiring terminals of the motor respectively.

1.3 Connect the contactor coil to the control circuit and the main contact to the motor. The specific wiring method is as follows:

• Connect the coil terminals of the contactor to the corresponding terminals of the control circuit.

• Connect the main contact terminals of the contactor to the three terminals of the motor respectively.

1.4 Check whether the wiring is correct and ensure there is no short circuit or wrong wiring.

1. Control circuit wiring

The control circuit of the auto-coupling step-down starting control cabinet mainly includes start button, stop button, time relay, contactor coil and other components. The wiring steps are as follows:

2.1 Connect the start button and stop button to the control circuit. The specific wiring method is as follows:

• Connect the normally open contact of the start button to the start loop of the control circuit.

• Connect the normally closed contact of the stop button to the stop loop of the control circuit.

2.2 Connect the time relay to the control circuit. The specific wiring method is as follows:

• Connect the coil terminals of the time relay to the corresponding terminals of the control circuit.

• Connect the normally open contact of the time relay to the starting circuit of the control circuit.

2.3 Connect the contactor coil to the control circuit. The specific wiring method is as follows:

• Connect the wiring terminals of the contactor coil to the corresponding terminals of the control circuit.

2.4 Check whether the wiring is correct and ensure there is no short circuit or wrong connection.

1. Protection circuit wiring

The protection circuit of the auto-coupling step-down starting control cabinet mainly includes overload protection, short circuit protection, phase loss protection and other components. The wiring steps are as follows:

3.1 Connect the overload relay to the three-phase circuit of the motor. The specific wiring method is as follows:

• Connect the three input terminals of the overload relay to the three-phase terminals of the motor respectively.

• Connect the normally closed contact of the overload relay to the stop loop of the control circuit.

3.2 Connect the short-circuit relay to the three-phase circuit of the motor. The specific wiring method is as follows:

• Connect the three input terminals of the short-circuit relay to the three-phase terminals of the motor respectively.

• Connect the normally closed contacts of the short-circuit relay to the stop loop of the control circuit.

3.3 Connect the phase loss protector to the three-phase circuit of the motor. The specific wiring method is as follows:

• Connect the three input terminals of the phase loss protector to the three-phase terminals of the motor respectively.

• Connect the normally closed contact of the phase loss protector to the stop circuit of the control circuit.

3.4 Check whether the wiring is correct and ensure there is no short circuit or wrong wiring.

1. Debugging and trial operation

4.1 Check all wiring to make sure there are no omissions or errors.

4.2 Set the power switch of the control cabinet to the "ON" position and observe whether the indicator light of the control cabinet lights up normally.

4.3 Press the start button and observe whether the motor starts normally. If the start is successful, the motor should run smoothly without abnormal sound or vibration.

4.4 Press the stop button and observe whether the motor stops normally.

4.5 Check whether the protection circuit is working properly. You can simulate overload, short circuit or phase loss faults to observe whether the protection circuit can cut off the power supply in time to protect the motor.

1. Precautions

5.1 During the wiring process, make sure that all connections are correct and secure to avoid short circuits or wrong connections.

5.2 During debugging and trial operation, be sure to pay attention to safety and avoid electric shock or mechanical injuries.

5.3 During use, regularly check the wiring and components of the control cabinet to ensure they are functioning properly.

5.4 If a fault is found in the control cabinet, the power supply should be cut off in time, the cause of the fault should be found and repaired.

1. in conclusion

The wiring method of the auto-coupling step-down starting control cabinet includes the wiring of the main circuit, control circuit and protection circuit. During the wiring process, attention should be paid to the correctness and safety of the wiring. Through debugging and trial operation, the normal operation of the control cabinet can be ensured. During use, regular inspection and maintenance of the control cabinet can extend its service life and ensure the safe operation of the motor.