Three-phase asynchronous motor after applying current to the stator

A three-phase asynchronous motor is a motor that is powered by a 380V three-phase AC power supply (with a difference of 120 degrees) at the same time. Since the rotor and stator rotating magnetic fields of the three-phase asynchronous motor rotate in the same direction and at different speeds, there is a difference in the rotational speed, so it is called a three-phase asynchronous motor. Three-phase asynchronous motors are induction motors. After the current is applied to the stator, part of the flux will pass through the short circuit and create a current in it.

The current in the short-circuit ring of the motor hinders the change of the magnetic flux, so that the magnetic flux generated by the part with the short-circuit ring and the part without the short-circuit ring has a phase difference, thereby forming a rotating magnetic field. After electrification, due to the relative motion between the rotor and the magnetic field, the rotor winding will induce electromotive force and current. That is to say, the rotating magnetic field and the rotor have a relative speed, and interact with the magnetic field to generate electromagnetic torque, which makes the rotor rotate and realize energy conversion. The working principle of the three-phase asynchronous motor: Assuming that the rotation of the magnetic field is counterclockwise, this is equivalent to the metal frame cutting the magnetic field line in a clockwise direction relative to the permanent magnet, and the metal frame is marked in a small circle in the direction of the figure.

2-pole motors with a center height of 180mm and below are generally double-layer windings, which can increase the fundamental winding coefficient by about 15%, that is, the actual number of turns can be reduced by about 15%, and the actual number of turns can be reduced while ensuring the same effective number of turns , while maintaining the same slot full rate, the conductor cross section can be increased, which will reduce the stator resistance and stator loss, and improve the efficiency of the motor. Due to the requirements of the original double-layer winding off-line process, the 2-pole motor adopts 2/3 short distance, too The short distance will make the magnetic field waveform very bad. After adopting the appropriate single-layer winding form, the magnetic field waveform is improved, which can reduce miscellaneous consumption, increase efficiency, reduce temperature rise, and improve start-up performance. The above two factors can improve efficiency. Energy saving.

Another feature of single-layer winding is that the number of turns per slot is flexible. It is feasible to increase or decrease one turn in single-layer winding or double-layer winding, but it is difficult to do it in single-layer winding and double-layer winding. Using single-layer And double-layer winding, you can choose a reasonable number of turns per pole and each phase in series to get a reasonable electromagnetic design scheme.