What is the difference between a three-phase synchronous motor and a three-phase asynchronous motor search
We know that the three-phase power supply phase phase difference is the voltage on the phase between 120 degrees, three of the three-phase asynchronous motor stator winding on the spatial orientation also sent 120 degrees, so that when zhongtong into the three-phase power supply in the stator winding, stator windings creates a rotating magnetic field, the stator windings creates a rotating magnetic field, rotor conductors (cage) will cut the lines of magnetic force of a rotating magnetic field and induced current, the current in the rotor conducting bar and interact with a rotating magnetic field to produce electromagnetic force, electromagnetic force produced by electromagnetic torque drive rotor rotating magnetic field along the direction of rotation. In general, the actual speed of the motor is below the rotational speed of the rotating field. We call the three-phase motor an asynchronous motor. Three-phase synchronous motor is the three-phase generators of different working condition. There are N on three-phase synchronous motor rotor of magnetic pole, the pole to N - S - N - S - order, coil magnetic poles, all of the coil in series, the final ends, pick up on the rotor shaft of two copper on the slip ring, copper slip ring and the shaft is insulated.
Synchronous motor as a generator running, the rotor winding with dc excitation at work, by external mechanical force to drive the rotor rotation, the direction of the n0 and torque T direction on the contrary, the stator of the induced emf (electromagnetic induction principle), and then the output voltage. When the synchronous motor runs, the rotor winding works with the dc excitation, the stator 3 phase alternating current, which generates the rotating magnetic field and the rotor synchronous rotation. Asynchronous motor and synchronous motor is the most fundamental difference between the stator any excitation, without excitation for asynchronous, should only produce relative movement, will have the effect of cutting magnetic induction line (or flux change), will produce electromagnetic induction force (i.e., ampere force). With the excitation, the stator can be regarded as a magnet, with fixed NS poles, which will be synchronized with the rotating field, so the synchronous motor is called. (magnets attract) three-phase asynchronous motor to spin the prerequisite is to have a rotating magnetic field, three-phase asynchronous motor stator winding is used to produce a rotating magnetic field
The principle of asynchronous motor is mainly to enter three phase alternating current in the stator, which produces a rotating magnetic field, which is n0, which is synchronous speed. Different magnetic poles, p, at the same frequency f = 50Hz, will produce different n0, n0 = 60f/p. Here's how it works: Symmetrical three phase winding ventilation with symmetrical three phase current, to produce a rotating magnetic field, magnetic field line cutting rotor winding, according to the principle of electromagnetic induction, rotor winding of e and I, rotor winding by the effect of electromagnetic force in the magnetic field, electromagnetic torque, which make the rotor rotation, the rotor output mechanical energy, drive the mechanical load. Rotor speed n < n0, so called asynchronous motor. S = (n0-n)/n0, which is called the slip rate, is an important parameter to the asynchronous (motion) machine. SN is the rated slip.
Synchronous motor is the ac motor, the stator winding is the same as the asynchronous motor. The rotational speed of its rotor is the same as the rotational field produced by the stator winding, so it is called the synchronous motor. As a result of this, the current of the synchronous motor is in phase over the voltage, the synchronous motor is a capacitive load. For this reason, in many cases, the synchronous motor is used to improve the power factor of the power supply system. The rated speed of the three-phase asynchronous motor is always lower than the synchronous speed, so it is called the asynchronous motor.
