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What is the effect of number of poles on speed of induction motor?
Motor Wiring and Number of Poles A 60 Hz power supply changes polarity 60 times per second, and a two-pole motor will spin at 3,600 rpm when connected to this source. A four-pole motor will only rotate at 1,800 rpm. For 50 Hz motors, the speed is 3,000 rpm with 2 poles, and 1,500 rpm with 4 poles.
What are poles in a induction motor?
AC Induction Motor Speeds Common AC motor units are constructed with either two or four poles. A magnetic field is created in the stator poles that induces resulting magnetic fields in the rotor which follow the frequency of the changing magnetic field in the stator.
What is the use of poles in motor?
The pole represents the number of permanent magnet poles for the rotating rotor, and a motor with one pair of N pole/S poles is called a two-pole motor.
What are the two types of induction motor?
Single-phase induction motors and three-phase induction motors are the two main types of induction motors.
What is difference between synchronous and induction motor?
Synchronous motors require an additional DC power source for energizing rotor winding. Induction motors do not require any additional power source. Synchronous motors require additional starting mechanism to initially rotate the rotor near to the synchronous speed. No starting mechanism is required in induction motors.
What is the speed of a 2 pole induction motor?
A 2 pole motor on 60 hz power has a synchronous speed of 3,600 rpm. For an induction motor, that will typically drop by a “slip” percentage, typically about 4% to 3,450 rpm. A 4 pole motor on 60 hz power has a synchronous speed of 1,800 rpm, induction less slip of 4% = 1,725 rpm.
Why are motors with different number of Poles?
If you are using 50Hz and have a two pole motor 60 x 50 / 1 = 3000 rpm. The induction motor will run at a slight less speed due to “slip” which is what gives the motor its torque.
What is the RPM of an induction motor?
The induction motor will run at a slight less speed due to “slip” which is what gives the motor its torque. For example 5.5kW, 400v, 2 pole motor will run at approximately 2880 rpm. For a four pole machine, 60 x 50 / 2 = 1500 rpm so the same size motor at 5.5kW, 400v but 4 poles will have a nominal speed of 1500rpm but will run near 1455 rpm.
How can I increase the torque of an induction motor?
Reduce the rpm to half, then you must increase the torque x 2 to maintain the same horsepower (kW) mechanical output. To double the torque of an induction motor, you must increase the amount of iron in the magnetic circuit. The motor frame size increases a couple of sizes.