What are the differences between AC motors and DC motors?
(1) the same structure, alternating current generator and DC motor structure are composed of stator, rotor, iron core, coil, magnetic pole, brush and so on.(2) the same electromagnetic applications are the applications of electro magnetic and magneto electric phenomena.(3) using the same conversion asynchronous motor, as long as the prime mover (such as turbine, diesel engine etc.) drag, rotor speed is n higher than the rotating magnetic field N1 synchronous speed, slip even if S= is negative, coupled with the exciting current, turned into AC asynchronous generator; DC motor, if the power part it changes the rotation for external power, armature winding and excitation winding end it on a DC voltage, the DC motor can also be used as a DC generator.(4) operation and maintenance are required to check the operation of the same operation, sound and vibration is normal, the ventilation is good, the bearing lubricating oil is sufficient, the stator windings and the temperature of each part is normal, there is no abnormal rotor brush spark voltage and current is in the rated range, chassis grounding or zero is good.
(Dan Xiang) the AC motor has only one winding, and the rotor is squirrel cage. When a single-phase sinusoidal current through the stator windings, the motor generates an alternating magnetic field, the magnetic field strength and direction for sinusoidal variation with time, but the spatial position is fixed, so it is also called the magnetic field is alternating pulsating magnetic field. The alternating pulsating magnetic field can be divided into two with the same speed, the rotation direction of the rotating magnetic field are on the contrary, when the rotor is at rest, the two rotating magnetic field generating torque of two equal and opposite in the rotor, the synthetic torque is zero, so the motor rotation
DC motor installed a constant magnetic field, current in the stator coil of electromagnetic force is created, it will move, but the direction of the current to continue to change, so will the use of brush, contact terminals. Therefore, the cost of construction is relatively high. Generally used in servo motor, speed measuring motor and excitation motor more.
The same thing is that their principles are the same, using the laws of electromagnetic inductionDifferent is the DC motor through the commutator to change the direction of the current. To get a transfer from the principle, I will not say, junior high school. It is through the AC motor into alternating current to produce a rotating magnetic field, in the motor, and then the law of electromagnetic induction.
