Electric Motor Speed Formula

The power supply frequency and.

Electric motor speed formula.

The full torque from zero speed is a major advantage for electric vehicles. For a 50 hz system the formula would be. P out τ ω. P number of poles.

Normally at it s top at operating speed. 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 synchronous speed for an electric induction motor is determined by. η m mechanical shaft speed.

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. Calculating the rpm resulting from a motor and speed reducer assembly requires only basic mathematical knowledge. S η sync η m η sync 100. Rpm shaft rotation speed or revolutions per minute.

The synchronous speed can be calculated as. N shaft rotation speed rev min rpm. F supply frequency hz. Note that when an ac motor is loaded the spinning magnetic field in the stator does not change speed.

The power produced by the motor depends on the speed of the motor and is. Slip of a motor can be found from the formula. 60hz is the most common frequency in the us. The rotor speed of a 4 pole induction motor at 50 hz is 1200 r min.

P number of poles. 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. N f 2 p 60 1. Note an induction motor will never reach its.

Where η sync 120 50 4 1500 r min. Poles number of poles of your motor. Output mechanical power of the motor could be calculated by using the following formula. This can be found on the nameplate of the motor.

Rotor speed η m 1200 r min. Where p out output power measured in watts w. The motor speed in rpm is calculated as n s 2 cdot 60 cdot dfrac f p. 50hz is the most common frequency outside the us.

Zero at 0 speed and. 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. The torque is the twisting force that makes the motor running and the torque is active from 0 to 100 operating speed. 50 x 60 x 2 6 000 no load rpm ã number of poles.

F frequency of electrical power supply hz cycles sec 1 s. Hz frequency or cycles sec. 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. For example 50 hz or 60 hz.

The motor speed calculator calculates the synchronous motor speed from the following parameters. For example 2 or 4. So for example if you have a 4 pole motor on 60 hz then rpm 60 2 4 60 1800 rpm. η sync speed of magnetic field.