synchronous motor and induction motor is a kind of commonly used ac motor. Features are: the steady state operation, the rotor speed and power grid frequency and constant relations between n = ns = 60 f/p, ns become synchronous speed. If the frequency of the power grid is kept constant, steady state when the synchronous motor speed constant is constant and has nothing to do with the size of the load. Synchronous motor are divided into synchronous generator and synchronous motor. In the modern power plant communication machine is given priority to with synchronous motor. Working principle, the establishment of the main magnetic field: passing a dc excitation winding excitation current, establish the excitation magnetic field, polarity and the establish the main magnetic field. Current-carrying conductor: three-phase symmetrical armature winding ACTS as the power winding, become the carrier of induction electric potential or induced current. Cutting movement: prime mover drag rotor (To the motor input mechanical energy)Excitation magnetic field, polarity and white with the axis of rotation and progressive cutting each phase winding of the stator (Equivalent to the winding conductor reverse cutting excitation magnetic field)。 Pieces of alternating electric potential: as the armature winding and the main magnetic field between the relative cutting motion, armature winding will sense if according to the size and direction changes periodically alternating voltage three phase symmetry. Through the lead wire, can provide the ac power. Paying degeneration and symmetry: due to the rotating magnetic field and polarity, makes the induction electric potential of the alternating polarity; Due to the symmetry of the armature winding, ensure that the three phase induction electric potential symmetry. Operation mode in pieces there are three main operation mode of the synchronous motor, namely as a generator, motor and compensation machine running. As a generator to run is the most important operation mode of the synchronous motor, as the motor running is another important operation mode of the synchronous motor. The power factor of synchronous motor can be adjusted, in the e799bee5baa6e79fa5e98193e78988e69d8331333264633563 does not require speed, using large-scale synchronous motor can improve the efficiency. In recent years, small in variable frequency asynchronous motor, synchronous motor is also called induction motor, is by the air gap interact to produce a rotating magnetic field and rotor winding induced current electromagnetic torque, so as to realize the mechanical and electrical energy into mechanical energy of an ac motor. Asynchronous motor according to the rotor structure is divided into two forms: a squirrel cage (Squirrel cage induction motor)And wound rotor asynchronous motor. Asynchronous motor for motor operation of asynchronous motor. Because of its rotor winding currents are induced, also called induction motor. Asynchronous motor is the most widely used in all kinds of motor, one of the biggest demand. Machine powered by electricity from country to country, about 90% for asynchronous motor, with small asynchronous motor accounted for about 70% or more. The total load in power system, power consumption accounts for a considerable proportion of the asynchronous motor. In China, the asynchronous motor power consumption accounts for about 60% of the total load. The basic characteristics of asynchronous motor, connected to other power rotor windings without, the stator current is taken directly from the ac power system; Compared with other motor, asynchronous motor has simple structure, manufacture, use, easy maintenance, high reliability, light weight, low cost. Three-phase asynchronous motor, for example, and with power, compared with the dc motor speed, the former and the latter half of the weight, the cost is only a third. Asynchronous motor is easy, according to the requirement of the different environmental conditions derived various series of products. It also has a close to the load characteristics of constant speed can meet the requirements of most industrial and agricultural production machinery drag. Its limitations is that its speed and rotating magnetic field of synchronous speed have a fixed slip (See the asynchronous motor)And speed control performance is poor in require a broad smooth speed range using occasions (Such as rolling mill drive, hoist, large machine tools, etc. )Economic, convenient, dc motor. In addition, the operation of the asynchronous motor, reactive power from the power system by excitation, which leads to the power factor of power system becomes bad. Therefore, in the high power, low speed occasions (Such as dragging the ball mill, compressor, etc. )Use synchronous motor is reasonable. Surface widely used, because of the large asynchronous motor production, its must have various varieties, specifications and all kinds of form a complete set of machinery. Therefore, paying special attention to the design of the asynchronous motor, production standardization, seriation, generalization. In all kinds of series products, the largest and the most widely used in production of series of three-phase asynchronous motor as the basic series; In addition to a number of derived series (On the basis of basic series as part of the change of export series), special series (Designed for special needs with special structure series)。 Starting to get more application in speed regulation system. Synchronous motor can also be connected into power grid as a synchronous condenser. When motor without any mechanical load, by adjusting the flow in the rotor excitation electric power grid from the inductive or capacitive reactive power, to improve the power factor or the purpose of the power grid voltage adjustment.
