I was using this video for the teaching of AC motor. It was produces by the US Airforce in 1969, I have to accept that it is rather an old video, black and white, but it had the main advantage that is was designed for training of the airforce personnel. Some of the new videos are intended for marketing rather than training.
AC motors are widely used in industry as well as in aircraft. It varies in size from a miniature size to the huge units.
There are many different types of AC motors, such synchronous, induction motors or hysteresis motors. The simplest and the most common type of motors is the induction motors. For that reason, the video concentrates on this motor.
A: Construction of Induction Motors.
It consists of three separate parts:
- end bell - at both end of the rotor and it consists of bearing assembly.
- the housing that contain the stator fields
- the rotor.
Because of it simplicity, it is easier to construct and robust.
B. Principle of operation
a. to demonstrate the principle, a simple gadget was designed with represent the rotating magnetic fields and the rotor. The field is spinned by hand and rotor will follow the rotating fields.
b.A model of rotating field and the rotor is shown proving the operation.
c. The production of rotating field - A good simple model was build to physically demonstrate the production of rotating field. Even two phases of 90degrees apart, the rotating field can be produced.
d. The production of electro-magnet in the rotor.
The rotor consists of wire conductors joint at the end by metal conductors. As there are the changing rotating magnetic field, current will flow in the rotor and produce magnet field.
Note: Requirement for the production of induction: conductor, magnetic field and relative motion.
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