The basic feature of the three-phase induction electric motor (MIT) is to operate at a speed somewhat below the synchronous speed. And this speed is defined by the number of poles and the frequency of power.
MIT has a major drawback in that the direct current output is very high at about 10 times its rated current. The reason for this high current is the low value of its equivalent equivalent impedance at the start, which is sometimes less than its rated speed. When you just want to smooth the starting of the electric motor without changing its speed, the soft-starter electronic device must be used, so that the current is as low as possible.
The advantages of the three-phase system over the single-phase system are:
– For the same size, three-phase generators and motors have higher power than single-phase motors;
– Three-phase transmission lines require less copper than single-phase transmission lines to carry the same power;
– Single-phase (other than collector) motors do not have their own starting; The three-phase can leave without outside assistance.