Soft starter motor on the use of advantages

- Aug 12, 2019-

Soft starter motor on the use of advantages


With the development of our country's economy, more and more applications of motor, motor starting method has been paid more and more attention.Generally speaking, the motor soft starter should be used when the motor power exceeds 30KW, otherwise it will seriously affect the use and operation of other equipment in the power grid and damage the motor itself.Can be said to be "soft starter use in the motor benefits a lot"!

Hazards of direct full-voltage starting of motor and benefits of soft starter of motor:

1. causing grid voltage fluctuation affecting operation of other power grid equipment

When the ac motor starts directly at full voltage, the starting current will reach 4~7 times of the rated current. When the capacity of the motor is relatively large, the starting current will cause a sharp drop in the voltage of the grid, affecting the normal operation of other equipment in the grid.

When the motor USES soft start cabinet, the starting current is generally 2-3 times of the rated current, and the voltage fluctuation of the power grid is generally within 10%, which has very little impact on other equipment.

2. Impact on the power grid

The impact on the power grid is mainly manifested in two aspects:

(1) super large motor directly starting large current impact on the grid is almost similar to the impact of three-phase short circuit on the grid, often cause power oscillation, make the grid lose stability.

(2) the starting current contains a large number of high harmonics, will cause high-frequency resonance with the network circuit parameters, causing relay protection misoperation, automatic control failure and other faults.

When the motor starts with soft start cabinet, the starting current is greatly reduced, and the above effects can be completely eliminated.

3. Damaging the insulation of a motor reduces the service life of the motor

(1) the joule heat generated by the large current repeatedly ACTS on the insulation outside the wire, which accelerates the aging of insulation and reduces its life.

(2) the mechanical force generated by the large current makes the wires rub against each other, reducing the insulation life.

(3) high voltage switch closing contact jitter phenomenon on the motor stator winding operation overvoltage, sometimes can reach the applied voltage of more than 5 times, such a high overvoltage will cause great harm to the insulation of the motor.