Electric Motor Rpm Formula

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

Electric motor rpm formula.

T inlb p hp 63025 n 1. 60hz is the most common frequency in the us. For dc motor torque formula. Below is a small calculator that will solve the ratio for you.

T ftlb p hp 5252 n 1b. Torque in imperial units can be calculated as. T v x i 2 x pi x n rpm 60 n rpm is the speed of the motor. T inlb torque in lb f.

At 1800 rpm a motor develops a 3 lb ft. Check the circle next to the item you are solving for and enter the remain three items in the spaces provided. Hz frequency or cycles sec. Electrical motor power velocity and torque equations.

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 speed of the motor can be found by using speed measurement devices. For calculating torque for dc motor. Motor torque changes with the speed.

In our example input electrical power of the motor is 0 22 a x 6 v 1 32 w output mechanical power is 1000 rpm x 2 x 3 14 x 0 00126 n m 60 0 132 w. N revolution per minute rpm alternatively. 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. Since the number of poles of athree phaseinduction motoris established when it is manufactured the only way to change the speed of the motor is to change thefrequency.

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. 1750 rpm 1000 rpm 3 5 inches d 2 d 2 6 125 inches. Poles number of poles of your motor. P hp horsepower delivered by the electric motor hp.

50hz is the most common frequency outside the us. Acthree phase induction motorrpmis determined by the formula. For a 50 hz system the formula would be. I input dc current.

V input dc voltage. Calculating the rpm resulting from a motor and speed reducer assembly requires only basic mathematical knowledge. Pulley and speed calculator. Note that when an ac motor is loaded the spinning magnetic field in the stator does not change speed.

1 ft lb f 1 356 nm. At no load you have maximum speed and zero torque. Per hp at 1200 rpm a motor develops a 4 5 lb ft. Here omega ω is equal to 2 x pi x n rpm 60.

Rpm shaft rotation speed or revolutions per minute. Hence motor torque t p ω. T ftlb torque lb f ft. Rpm 120 frequency of poles in the motor.