Circuit and working principle of resistance split-phase starting single-phase motor

The starting winding of resistance split-phase motor is wound with thinner wires with fewer turns, and the running winding is wound with thicker wires with more turns. Comparing the two, the former has large resistance and small inductance, while the latter has small resistance and large inductance.

When two windings are connected in parallel to a single-phase AC power supply, the phase angle ω2 of the current I2 flowing through the starting winding is smaller than that of the voltage U, while the phase angle ω 1 of the current I 1 flowing through the running winding is larger than that of the voltage U. ..

Therefore, the single-phase current is divided into two-phase current, and the phase difference ω = ω 1-ω 2. Although the difference between these two currents and the two-phase current is not 90 degrees, their phase angle difference ω is enough to generate a rotating magnetic field with the same properties as the two-phase current.

After the resistance split-phase motor is successfully started, the starting winding must be disconnected, and it will overheat and burn out after working for a long time.

Starting circuit diagram of resistance split-phase motor;

Extended data:

Single-phase motor refers to asynchronous motor powered by 220V AC single-phase power supply. Because the 220V power supply is very convenient and economical, and the domestic electricity consumption is also 220V, the single-phase motor is not only used in production, but also closely related to people's daily life, especially with the increasing improvement of people's living standards, the consumption of single-phase motors for household appliances is also increasing.

In terms of production, there are micro-pumps, refiners, threshers, shredders, woodworking machinery, medical instruments and so on. There are electric fans, hair dryers, exhaust fans, washing machines, refrigerators, etc. There are many kinds, but the power is small.

Reference source: Baidu Encyclopedia-Single-phase Motor