it is a 20 pole motor
A 3-pole motor has a smother torque curve.
A 2-Pole motor runs twice as fast as a 4-pole motor. The 2-pole motor has 2 windings at 180 degrees apart and the four pole motor has four windings at 90 degrees apart. The rotor tries to move from pole to pole with each half cycle of the AC current so the motor no-load speed for 60 cycle current is 2x3600/#poles. This is 1800 rpm for a 4-cycle motor and 3600 rpm for a 2-pole motor.
A 2-pole motor has about 1.5 ft-lbs of torque per horsepower where a 4-pole motor has 3 ft-lbs of torque. also the speed of a 2-pole motor is twice that of a 4-pole motor. The speed of a motor is determined by: speed=(120 x freq)/no. of poles At 60 Hz, a 4-pole motor is about 1800 rpm where a 2-pole motor is 3600
shadded pole motor
electric and magnetic go hand in hand. One needed to produce other. Motor no magnetic pole, motor no work.
because its possible only where pole changing arrangements are given and pole changed motor draws more current then its actual pole which damages its windings.
shaded pole
Relationship between motor rpm and no of poles
The motor used in a table fan is usually a shaded pole motor.
The number of poles in a motor will determine the speed of that motor. n=speed, f=frequency, p=# of poles. n=(120f)/p So a 6 pole motor is rated to operate at n=(120*60)/6=1200 rpm. assuming 60Hz frequency Or a 8 pole motor is rated to operate at 900 rpm. Of course due to slip the rotor will always spin slightly slower.
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