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Basic wiring method of the main circuit:

1. Power input terminal (L1, L2, L3)

The main circuit input terminal of the soft starter is connected to the power supply, usually a three-phase AC power supply.

Connect the three-phase wires of the power supply to L1, L2, and L3 of the soft starter input terminal in sequence.

Make sure that the voltage and frequency of the power supply meet the rated requirements of the soft starter.

2. Output terminal (T1, T2, T3)

The output terminal of the soft starter (usually marked as T1, T2, T3) is connected to the input terminal of the motor.

Note that the wiring sequence of the output terminal must be consistent with the phase sequence of the input terminal to ensure the forward direction of the motor.

When it is necessary to connect to the inverter in some occasions, please confirm the compatibility.

3. Bypass contactor

After the start is completed, the soft starter may switch to bypass operation to reduce its heat generation and power consumption due to long-term power supply.

The bypass contactor is connected in parallel to the output terminal (T1, T2, T3) of the soft starter and realizes automatic switching through the control circuit.

The capacity of the bypass contactor must match the rated current of the motor.

4. Protection components

Circuit breaker/fuse: used to protect the main circuit from short circuit and overload.

Thermal relay: used for motor overload protection, usually connected to the motor end or downstream of the soft starter.

Surge protection device: prevents instantaneous high voltage from damaging the equipment.

5. Grounding (PE)

The grounding terminal of the soft starter must be reliably connected to the earth to ensure safe operation of the equipment.

The motor housing also needs to be well grounded.

Summary of wiring steps:

Make sure the equipment is powered off.

Connect the three-phase power supply according to the input (L1, L2, L3).

Connect to the motor according to the output (T1, T2, T3).

Install necessary protection devices and bypass contactors.

Confirm that the grounding is reliable.

Power on the test to check the phase sequence and operating status.

Notes:

Be sure to read the manual of the soft starter carefully before wiring.

Use cables of appropriate specifications to avoid overload.

Confirm that the rated parameters of the motor and soft starter match before starting.

Check the tightness of the wiring regularly to prevent looseness and cause failure.