Objective:
– To demonstrate the operation of an induction motor.
Apparatus:
- Rotor
- U-magnet (special)
- Pie plate on pivot and stand
- Four-pole rotating-field magnet
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Method:
The four-pole electromagnet is connected with a capacitor in such a way that the alternating current phase angle ‘leads’ the next pole by 90 degrees, setting up a rotating magnetic field. The eddy currents induced in the suspended pie plate oppose the rotating field. The force created causes the pie plate to rotate. The closer the plate to the magnet the faster the plate will rotate.
A variation with the same results can be shown using an RD-1 rotor set vertically with a U-magnet clamped by its center bolt to the rotor head. The pie plate is suspended above the poles, giving the same result as before.