Electric Motor Speed Formula

It is motor speed and torque the turning force of the motor.

Electric motor speed 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. The torque is the twisting force that makes the motor running and the torque is active from 0 to 100 operating speed. Rpm shaft rotation speed or revolutions per minute. 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 full torque from zero speed is a major advantage for electric vehicles. The synchronous speed for an electric induction motor is determined by. The motor speed in rpm is calculated as n s 2 cdot 60 cdot dfrac f p. The synchronous speed can be calculated as.

The power produced by the motor depends on the speed of the motor and is. Zero at 0 speed and. Where p out output power measured in watts w. 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.

Hz frequency or cycles sec. This can be found on the nameplate of the motor. 50 x 60 x 2 6 000 no load rpm ã number of poles. P out τ ω.

Motors supposed to do some work and two important values define how powerful the motor is. S η sync η m η sync 100. P number of poles. Poles number of poles of your motor.

For example 2 or 4. Where η sync 120 50 4 1500 r min. Slip of a motor can be found from the formula. Rotor speed η m 1200 r min.

η m mechanical shaft speed. The power supply frequency and. The number of poles in the motor winding. For a 50 hz system the formula would be.

50hz is the most common frequency outside the us. F supply frequency hz. The motor speed calculator calculates the synchronous motor speed from the following parameters. N shaft rotation speed rev min rpm.

For example 50 hz or 60 hz. 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. So for example if you have a 4 pole motor on 60 hz then rpm 60 2 4 60 1800 rpm.

Calculating the rpm resulting from a motor and speed reducer assembly requires only basic mathematical knowledge. The rotor speed of a 4 pole induction motor at 50 hz is 1200 r min. 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. Output mechanical power of the motor could be calculated by using the following formula.

η sync speed of magnetic field. F frequency of electrical power supply hz cycles sec 1 s. Note an induction motor will never reach its. Normally at it s top at operating speed.