Electric Motor Rpm Formula

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.

Electric motor rpm formula.

T inlb p hp 63025 n 1. 50 x 60 x 2 6 000 no load rpm ã number of poles. 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. P hp horsepower delivered by the electric motor hp.

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. Rpm shaft rotation speed or revolutions per minute. Below is a small calculator that will solve the ratio for you. T v x i 2 x pi x n rpm 60 n rpm is the speed of the motor.

For dc motor torque formula. Acthree phase induction motorrpmis determined by the formula. Pulley and speed calculator. 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.

Per hp at 575 volts a 3 phase motor draws 1 amp per hp at 460 volts a 3 phase motor draws 1 25 amp per hp at 230 volts a 3 phase motor draws 2 5 amp per hp at 230 volts a single phase motor draws 5 amp per hp. N revolution per minute rpm alternatively. So for example if you have a 4 pole motor on 60 hz then rpm 60 2 4 60 1800 rpm. For calculating torque for dc motor.

50hz is the most common frequency outside the us. V input dc voltage. The speed of the motor can be found by using speed measurement devices. T ftlb p hp 5252 n 1b.

Per hp at 1200 rpm a motor develops a 4 5 lb ft. 1 ft lb f 1 356 nm. Here omega ω is equal to 2 x pi x n rpm 60. Hence motor torque t p ω.

Torque in imperial units can be calculated as. For a 50 hz system the formula would be. At 1800 rpm a motor develops a 3 lb ft. I input dc current.

Electrical motor power velocity and torque equations. T ftlb torque lb f ft. 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. Rpm 120 frequency of poles in the motor.

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. Hz frequency or cycles sec. Calculating the rpm resulting from a motor and speed reducer assembly requires only basic mathematical knowledge.

Motor torque changes with the speed. T inlb torque in lb f. 1750 rpm 1000 rpm 3 5 inches d 2 d 2 6 125 inches. 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.