The synchronous electric motor is an AC motor, and the stator winding is the same as that of the asynchronous motor. The rotating speed of the rotor is the same as that of the rotating magnetic field produced by the stator winding, so it is called a synchronous motor. Because of this, the current of the synchronous motor is ahead of the voltage in the phase, that is, the synchronous motor is a capacitive load. For this reason, at many times, the synchronous electric motor is used to improve the power factor of the power supply system.
There are roughly two types of synchronous electric motor in the structure:
1, the rotor is excited by direct current. The rotor of the rotor is made of pole type. The magnetic field coils mounted on the core of the magnetic pole are connected in series, and have polarity with alternating polarity. Two leads are connected to two slip rings mounted on the shaft. The magnetic field coil is excited by a small DC generator or battery. In most of the synchronous motors, the DC generator is mounted on the motor shaft to supply the exciting current of the rotor pole coil. Since the synchronous motor can not be automatically started, the rotors are also equipped with squirrel cage windings as an electric motor. The squirrel cage winding is placed around the rotor, and the structure is similar to that of the asynchronous motor. When a three-phase AC power is connected to the stator winding, a rotating magnetic field is generated in the motor, and the induced magnetic current is generated by squirrel cage winding, so that the motor rotates. The rotation of the motor, the speed slowly increased to slightly lower than the speed of the rotating magnetic field, the magnetic field of the rotor coil via the DC power supply excitation, the rotor formed on certain magnetic poles, the magnetic poles will attempt to track the rotating magnetic poles on the stator, so as to increase the rate of the motor rotor and rotating magnetic field rotation until the synchronization so far.
2. The synchronous motor that does not need excitation of the synchronous motor rotor without excitation can be applied to the single-phase power supply, and can also be used in multiphase power supply. In this motor, there is a stator winding similar to the stator of the split phase motor or multiphase motor, and there is a squirrel cage rotor at the same time, and the rotor surface is cut into a plane. So it belongs to the polar rotor, the rotor pole is made of a magnetized steel, and it can always keep magnetic. The squirrel cage winding is used to generate the starting torque. When the motor rotates to a certain speed, the rotor's apparent pole will synchronize with the current and frequency of the stator coil. The polarity of the salient pole is induced by the stator, so its number should be equal to the pole number of the stator. When the motor goes to its proper speed, the squirrel cage winding will lose its function. The maintenance of rotation depends on the synchronization of the rotor and the pole with the magnetic pole of the stator.
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Lucy | Director Manager
WINGO STAR MOTOR
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