Electric Motor Speed Formula

The synchronous speed for an electric induction motor is determined by.

Electric motor speed formula.

50 x 60 x 2 6 000 no load rpm ã 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. Calculating the rpm resulting from a motor and speed reducer assembly requires only basic mathematical knowledge. Where p out output power measured in watts w.

η m mechanical shaft speed. This can be found on the nameplate of the motor. The motor speed calculator calculates the synchronous motor speed from the following parameters. N shaft rotation speed rev min rpm.

60hz is the most common frequency in the us. The number of poles in the motor winding. Poles number of poles of your motor. Note that when an ac motor is loaded the spinning magnetic field in the stator does not change speed.

Motors supposed to do some work and two important values define how powerful the motor is. Note an induction motor will never reach its. Zero at 0 speed and. P number of poles.

The torque is the twisting force that makes the motor running and the torque is active from 0 to 100 operating speed. It is motor speed and torque the turning force of the motor. For example 2 or 4. Hz frequency or cycles sec.

S η sync η m η sync 100. The power produced by the motor depends on the speed of the motor and is. 50hz is the most common frequency outside the us. The power supply frequency and.

F supply frequency hz. The synchronous speed can be calculated as. The motor speed in rpm is calculated as n s 2 cdot 60 cdot dfrac f p. For example 50 hz or 60 hz.

Rpm shaft rotation speed or revolutions per minute. Rotor speed η m 1200 r min. η sync speed of magnetic field. Slip of a motor can be found from the formula.

F frequency of electrical power supply hz cycles sec 1 s. 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. P out τ ω. Output mechanical power of the motor could be calculated by using the following formula.

N f 2 p 60 1. P number of poles. Normally at it s top at operating speed. 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.

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