Common Faults and Solutions for Soft Starter Maintenance

1. During the debugging process, the starter reports a phase loss fault, the soft starter fault light is on, and the motor does not respond. The possible causes of the fault are:

(1) When the starting method is live, the operation sequence is incorrect (the correct operation sequence should be to send the main power first and then the control power);

(2) The power supply is phase-lost and the soft starter protection is activated (pleasecheck the power supply);

(3) The output end of the soft starter is not connected to the load (the soft starter can only work normally after the output end is connected to the load)

2. During the use of the user, the bypass contactor does not attract after the start is completed. The possible causes of the fault are:

(1) During the starting process, the protection device malfunctions due to under-setting. (Re-set the protection device)

(2) During debugging, the parameters of the soft starter are not set properly. (It is mainly aimed at soft starters below 55KW, and the parameters of the soft starter are reset)

(3) The control circuit has poor contact (pleasecheck the control circuit)

3. During the starting process, the user occasionally experiences the phenomenon of the air switch tripping. The reasons for the failure are:

(1) The setting value of the long delay of the air switch is too small or the air switch selection is not compatible with the motor. (The parameters of the air switch are appropriately increased or the air switch is re-selected)

(2) The starting voltage parameter of the soft starter is set too high or the starting time is too long. (According to the load conditions, the starting voltage is appropriately reduced or the starting time is appropriately shortened.)

(3) During the starting process, due to the large fluctuation of the grid voltage, it is easy to cause the soft starter to issue an erroneous command. The phenomenon of early bypass occurs. (It is recommended that users do not start high-power motors at the same time)

(4) Start at full load during starting (pleasetry to reduce the load during starting)

4. When the user uses the soft starter, the display screen is blank or garbled, and the soft starter does not work. The possible causes of the failure are:

(1) The vibration generated by external components during the use of the soft starter loosens the internal connection of the soft starter (open the cover of the soft starter and re-tighten the display connection)

(2) The soft starter control board is faulty (contact the manufacturer to replace the control board)

5. The soft starter reports a fault during startup, the soft starter does not work, and the motor does not respond. The possible causes of the failure are:

(1) The motor is missing a phase (pleasecheck the motor and peripheral circuits)

(2) The main component of the soft starter, the thyristor, is short-circuited (check whether the motor and the grid voltage are abnormal. Contact the manufacturer to replace the thyristor)

(3) The filter board is short-circuited (replace the filter board)

6. When the soft starter starts the load, the start timeout occurs. The soft starter stops working and the motor stops freely. The causes of the fault are:

(1) Parameter setting is unreasonable (re-adjust the parameters, increase the starting voltage appropriately, and increase the time appropriately)

(4) Start at full load during startup (the load should be reduced as much as possible during startup)

7. During the startup process, the current is unstable and the current is too large. The reasons may be:

(1) The ammeter indication is inaccurate or does not match the transformer (replace a new ammeter)

(2) The grid voltage is unstable and fluctuates greatly, causing the soft starter to malfunction (contact the manufacturer to replace the control board)

(3) The soft starter parameter setting is unreasonable. (Re-adjust the parameters)

8. The soft starter starts repeatedly. The causes of the fault are:

During the startup process, the peripheral protection components are activated and the contactor cannot be attracted, causing the soft starter to start repeatedly (check the peripheral components and circuits)

9. The overheating fault light is on during startup and the soft starter stops working:

(1) Frequent startups cause the temperature to be too high, causing the soft starter overheating protection to operate. (The number of soft starter starts should be controlled within 6 times per hour, especially for heavy loads)

(2) During the starting process, the protection element is activated, so that the contactor cannot be bypassed, and the soft starter works for a long time, causing the protection to be activated. (Check the peripheral circuit)

(3) The load is too heavy and the starting time is too long, causing overheating protection. (When starting, reduce the load as much as possible)

(4) The parameter setting of the soft starter is unreasonable. The time is too long and the starting voltage is too low. (Increase the starting voltage)

(5) The cooling fan of the soft starter is damaged and cannot work normally. (Replace the fan)

10. Thyristor damage:

(1) When the motor is started, the overcurrent will break down the soft starter (check whether the soft starter power matches the motor power and whether the motor is started with load)

(2) The cooling fan of the soft starter is damaged (replace the fan)

(3) Frequent starting and high temperature will damage the thyristor (control the number of starts)

(4) The filter board is damaged (replace the damaged component)