What are the three-phase asynchronous motor starting methods?
For the three-phase asynchronous motor, no matter its rotor design, stator manufacturing, or rotor manufacturing, these two situations are involved.
When a single delta connection is used, the three-phase asynchronous motor can still start normally in the case of phase loss. However, under the long-term operation of the rotor of the three-phase asynchronous motor, if there is no starting torque, the starting current will increase, and the voltage of the grid will decrease. Happening. For a three-phase asynchronous motor with a delta connection, the line voltage is 3 times the root of the phase voltage, and if it is a star connection, it is 3 times the root of the phase voltage.
When the motor is connected in star-shaped operation, since the starting current is proportional to the square of the power supply voltage, the stator current of the motor increases in the star-connected state, and when the motor enters the rated capacity of the rated capacity, it cannot be restarted. And if it is, the line current is equal to 3 times the root sign of the phase current, that is, the line current per minute, that is, the lights gradually brighten and the lights gradually brighten. For a three-phase asynchronous motor with delta connection, the line voltage is three times the root sign of the phase voltage. If it is a star-connected motor, the line current is equal to the phase current. Under the state of rated current, the rotor current of the motor is the phase current. Root number 3 times.
When the motor is connected in a delta operation, since the current is proportional to the power supply voltage, the stator current of the motor is also three times the root sign of the phase current under the rated capacity.
When the motor is connected in star operation, the stator current of the motor is proportional to the root sign of the power supply voltage and the phase voltage, so the rotor current and the stator current of the motor interact with the rated current.
When the motor is connected in star operation, due to the relationship between the rated voltage and the rated current, the rated current is proportional to the square of the rated current, so the rotor current density of the motor is also the largest.
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