The difference between dc motor and ac motor
The speed adjustment method is different: The reason that the stator magnetic field is rotating is the three-phase symmetric alternating current which is 120 degrees behind each other, and the stator field is changed by alternating current. By changing the speed of alternating current changes, the speed of the motor can be changed. Dc power supply, dc motor is the same constant voltage, and the coil connected to the actual location change of formation, and connected to the coil of the actual location of the change only associated with the speed of the rotor rotation; As long as the speed of the rotor is changed, the rotor speed is proportional to the voltage, and the change of voltage can change the speed, which is the speed adjustment.
Different speed control accuracy: Dc speed control does not change the load properties of the motor, and ac speed change the property of load. In other words, the frequency of the alternator is different. The resistance of the dc motor is constant while the voltage is different. Ac speed adjustment, due to unstable, it is difficult to realize fine speed adjustment. Dc speed adjustment, due to stability, it is easy to achieve fine speed adjustment, and several millivolt speed can be resolved.
Ac motor is only the stator winding and rotor cage shape is commonly, when during a stator winding in three-phase alternating current (ac), to produce a rotating magnetic field, rotor cutting lines of magnetic force movement, the induced electromotive force and induced magnetic fields, are produced by the interaction of two magnetic field drive motor rotation. Dc motors have two windings, a stator winding, a rotor winding, the stator zhongtong with direct current, a fixed magnetic field generated, passing a current in the rotor is, based on the function of electric conductor in magnetic field by force, and the effect of the rotor after electrify force, so that it rolls up, adjust the size of the current in the rotor, can change the speed of the motor, dc motor speed smooth, can realize stepless speed regulation. Now frequency conversion technology is mature, so use more and more frequency control of motor speed, dc motor without the answer
