3 phase motors and its uses
INTRODUCTION.
An AC motor is an electric motor that is driven by an alternating current. It consists of two basic parts, an outside stationary stator having coils supplied with AC current to produce a rotating magnetic field, and an inside rotor attached to the output shaft that is given a torque by the rotating field.
There are two types of AC motors, depending on the type of rotor used. The first is the synchronous motor, which rotates exactly at the supply frequency or a submultiple of the supply frequency. The magnetic field on the rotor is either generated by current delivered through slip rings or by a permanent magnet.
The second type is the induction motor, which turns slightly slower than the supply frequency. The magnetic field on the rotor of this motor is created by an induced current.
An AC motor is an electric motor that is driven by an alternating current. It consists of two basic parts, an outside stationary stator having coils supplied with AC current to produce a rotating magnetic field, and an inside rotor attached to the output shaft that is given a torque by the rotating field.
There are two types of AC motors, depending on the type of rotor used. The first is the synchronous motor, which rotates exactly at the supply frequency or a submultiple of the supply frequency. The magnetic field on the rotor is either generated by current delivered through slip rings or by a permanent magnet.
The second type is the induction motor, which turns slightly slower than the supply frequency. The magnetic field on the rotor of this motor is created by an induced current.
3 Phase Motors
3 Phase Electric Motors Are More Efficient
The most common type of 3 phase electrical load is the 3 phase electric motor. A 3 phase motor is more compact and less costly than a 1-phase motor of the same voltage class and rating; also 1-phase AC motors above 10 HP (7.5 kW) are not as efficient and thus not usually manufactured. A 3 phase induction motor has a simple design, inherently high starting torque, and high efficiency. Such motors are applied in industry for 3 phase pumps, fans, blowers, compressors, conveyor drives, and many other types of 3 phase motor-driven equipment. There are a lot of benefits to using a 3 phase electric motor over a single phase electric motor. Large air conditioning equipment (for example, most air conditioning units above 2.5 tons (8.8 kW) cooling capacity) use 3 phase motors for reasons of economy and efficiency. Read more about other 3 phase power loads. Read more about 3 phase motors below.
Most electric power is distributed in the form of 3-phase AC. Therefore, before proceeding any further you should understand what is meant by 3 phase power. Basically, the power company generators produce electricity by rotating (3) coils or windings through a magnetic field within the generator . These coils or windings are spaced 120 degrees apart. As they rotate through the magnetic field they generate power which is then sent out on three (3) lines as in three-phase power. 3 phase transformers must have (3) coils or windings connected in the proper sequence in order to match the incoming power and therefore transform the power company voltage to the level of voltage we need and maintain the proper phasing or polarity.
3 Phase Power Is More Efficient Than Single Phase
Three phase electricity powers large industrial loads more efficiently than single-phase electricity. When single-phase electricity is needed, It is available between any two phases of a three-phase system, or in some systems , between one of the phases and ground. By the use of three conductors a 3 phase system can provide 173% more power than the two conductors of a single-phase system. Three-phase power allows heavy duty industrial equipment to operate more smoothly and efficiently. 3 phase power can be transmitted over long distances with smaller conductor size.
reference
http://www.engineersedge.com/motors/generators_types.htm
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