Why Doesn't The Rotation Of A Single-phase Motor Change When It Is Connected To The Mains?

Single-phase motor refers to an asynchronous motor powered by a 220V AC single-phase power supply. Because 220V power supply is very convenient and economical, and our country's household electricity is also 220V, single-phase motors are 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 daily life, single-phase motors are the most widely used; when single-phase motors are connected to the power supply, sockets are generally used, whether it is a two-hole or three-hole socket, the power supply motor works on the live wire and the neutral wire. I have never considered which is the live wire and which is the neutral wire, but the motor has never had a reverse rotation problem.

Since the phase-shifting effect of the capacitor is relatively obvious, as long as a capacitor with an appropriate capacity is connected in series with the starting winding, the current phase difference between the two windings can be made close to 90°, and the synthetic rotating magnetic field at this time is close to the circular rotating magnetic field, so the motor The starting torque is large, and the starting current is small.

As we talked to you in the previous article, what determines the direction of the motor is the connection between the capacitor and the winding. Let's take the following figure as an example, which is the circuit diagram of a single-phase and one-way rotating motor. No matter which one is the live wire in the power supply, it is not It will change the connection relationship between the capacitor and the winding, and it will not change the phase relationship between the two windings, and naturally it will not affect the motor steering.

From a safety point of view, the current power sockets on the market are all 3 holes, that is, with a ground wire; the motor plug corresponding to the power supply also has a ground wire. In practical applications, as long as the power supply and motor wiring are normal, both The natural connection can ensure the normal operation of the motor.

Ungrounded electrical appliances can be used normally, but there are certain safety hazards. If electrical appliances such as washing machines and refrigerators have leakage faults, the shell will be charged, and electric shock accidents may occur easily.