Wannan motor three-phase asynchronous motor manufacturers to decrypt the star delta starting principle

In actual use process, sometimes motor power 11kw requires star delta start, such as rated power 11kw wind machine at startup current is 7-9 times (100a), according to the normal configuration of thermal relay is fundamental to start not closing door is useless), thermal relay with too high and law to protect the motor, it is proposed that the adoption of star delta starter.

The starting current of the motor is proportional to the supply voltage, and the starting current of the power grid is only 1/3 of the full voltage starting current, so the starting torque is only 1/3 of the full voltage starting torque. Star delta starter is a step-down to start, it is to sacrifice the power at the expense of reduce the starting current of the, so can not be generalized to the size of the motor power to determine whether the star delta start depends on the load is what kind of. When the starting load is light, running load of negative load can be used in the case of star delta starting, the starting current of the squirrel cage motor is 5-7 times, and the grid voltage requirement is generally positive and negative 10%, in order to make the motor starting current does not have a big impact on the power grid voltage, can be used to start the star triangle. General requirements for the squirrel cage motor power over the transformer rated power of 10% when the use of the star triangle start.

The motor is connected with the star in the starting of the motor. When the motor is started, the motor is switched to a triangular connection (and the switch is quickly switched on).

When the load on the motor starting torque without strict requirements but also restrict the motor starting current, motor to meet 380V/ delta connection conditions, and the normal operation of the motor stator winding resistance is connected in a triangle to the star delta starting method.