How to adjust the speed of the motor through stator voltage regulation?

Update:07 Apr 2020

When the load torque is constant, as the motor stator v […]

When the load torque is constant, as the motor stator voltage decreases, the main magnetic flux decreases, the rotor induced electromotive force decreases, the rotor current decreases, the electromagnetic force received by the rotor decreases, the slip rate s increases, and the speed decreases to achieve speed The purpose of adjustment; in the same way, the stator voltage increases and the speed increases.

The advantages of limingmotor motor voltage and speed regulation are smooth speed regulation. When the closed-loop system is used, the mechanical characteristics are hard and the speed regulation range is wide. The disadvantage is that at low speeds, the slip power loss is large, the power factor is low, the current is large, and the efficiency low. The speed regulation is neither constant torque speed regulation nor constant power speed regulation, which is more suitable for the load of fan pump characteristics. The indoor fan on the split machine uses the stator voltage to adjust the speed.

According to the feedback signal of the fan speed, the phase angle of the thyristor SCR conduction is controlled, thereby controlling the input voltage of the fan stator to control the wind speed of the fan.

Three-phase windings that differ from each other by 2π / 3 rad electrical angles in space can be rotated in time by a phase difference of 2π / 3 rad phase angles, which can produce a rotating magnetic field. Rotating magnetic fields can also be generated by passing two-phase windings of rad electrical angle with a time difference of π / 2 rad phase angle. The function of the capacitor C is to shift the phase of one phase current to produce an alternating current with a phase angle difference of π / 2 rad from each other in time. The internal structure of the fan is guaranteed.