Electric Motor Speed Formula

Using this formula you can see that a four pole motor operating on the bench under no load conditions runs at 1 800 rpm 7 200 ã 4 poles.

Electric motor speed formula.

η sync speed of magnetic field. P number of poles. The motor speed in rpm is calculated as n s 2 cdot 60 cdot dfrac f p. 50 x 60 x 2 6 000 no load rpm ã number of poles.

This can be found on the nameplate of the motor. 60hz is the most common frequency in the us. Motors run at a specific revolutions per minute rpm and a speed reducer is needed if you want to keep that motor but have a lower rpm. The number of poles in the motor winding.

Where p out output power measured in watts w. For a 50 hz system the formula would be. A four polethree phase induction motorwhen operated at 60 hz will be very close to 1800rpm synchronous speed the rated full load speed will be less than synchronous speed by the value of slip a four polethree phase induction motorwith a ratedfull loadspeed of 1750 has a slip rating of 2 7 by formula. Typical no load or synchronous speeds for an ac fractional horsepower motor are 1800 or 3600 rpm and 1000 5000 rpm for dc fractional hp motors.

So for example if you have a 4 pole motor on 60 hz then rpm 60 2 4 60 1800 rpm. For example 50 hz or 60 hz. Dc controls adjust speed by varying the voltage sent to the motor this differs from ac motor controls which adjust the line frequency to the motor. Hz frequency or cycles sec.

P number of poles. Normally at it s top at operating speed. S η sync η m η sync 100. N f 2 p 60 1.

Output mechanical power of the motor could be calculated by using the following formula. Calculating the rpm resulting from a motor and speed reducer assembly requires only basic mathematical knowledge. P out τ ω. Rpm shaft rotation speed or revolutions per minute.

Motors supposed to do some work and two important values define how powerful the motor is. The rotor speed of a 4 pole induction motor at 50 hz is 1200 r min. Zero at 0 speed and. The full torque from zero speed is a major advantage for electric vehicles.

For example 2 or 4. Rotor speed η m 1200 r min. 50hz is the most common frequency outside the us. N shaft rotation speed rev min rpm.

Poles number of poles of your motor. The synchronous speed for an electric induction motor is determined by. The torque is the twisting force that makes the motor running and the torque is active from 0 to 100 operating speed. The power supply frequency and.

F supply frequency hz. Note that when an ac motor is loaded the spinning magnetic field in the stator does not change speed. Note an induction motor will never reach its. Where η sync 120 50 4 1500 r min.

F frequency of electrical power supply hz cycles sec 1 s. η m mechanical shaft speed. It is motor speed and torque the turning force of the motor. Slip of a motor can be found from the formula.