The starting winding of a resistive split-phase motor is wound with thinner wires and has fewer turns, while the running winding is wound with thicker wires and has more turns. Comparing the two, the former has large resistance and small inductance, while the latter has small resistance and large inductance.
When the two windings are connected in parallel to a single-phase AC power supply, the current I2 through the starting winding lags behind the phase angle ω2 of the voltage U by a small amount, while the current I1 through the running winding lags behind the phase angle of the voltage U ω1 is larger.
Thus, the single-phase current is divided into two-phase currents with a phase difference ω = ω1-ω2. Although these two currents are not 90° different like the two-phase current, their phase angle difference ω has It is enough to produce 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. The starting winding will overheat and burn if it works for a long time.
Starting circuit diagram of resistance split-phase motor:
Extended information:
Single-phase motor refers to an asynchronous motor powered by 220V AC single-phase power supply. electric motor. Because 220V power supply is very convenient and economical, and household electricity is also 220V, single-phase motors are not only used in large quantities in production, but are also closely related to people's daily lives, especially as people's living standards improve day by day. The use of single-phase motors in household electrical equipment is also increasing.
In production, micro water pumps, refiners, threshers, crushers, woodworking machinery, medical equipment, etc. are used. In daily life, there are electric fans, hair dryers, exhaust fans, washing machines, electric fans, etc. Refrigerators, etc., have more types, but less power.
Reference source: Baidu Encyclopedia-Single-phase motor