# Motor selection

stan
Hi

i need a variable speed motor. I came across a catalog which has a motor with a base speed of 1800rpm and power of 1hp and it is of a variable torque type.

What does base speed means here? Does it means it allows speed from 0 to 1800rpm? and does its power of 1hp is constant for various rpm and torque?

So for example if the output is at 300rpm, could i safely assume that the torque is = 1hp/300rpm? likewise for say 500rpm, its torque is 1hp/500rpm?

stan

LunchBox
Okay, as a good standard metric, the power output of a motor is proportional to the cube of the rpm. So your engine, as described, delivers 1 hp AT 1800 rpm. Using the cube metric, the engine should deliver about 0.005 hp at 300 rpm and 0.02 hp at 500 rpm.

You are correct in that the power divided by the rpm is the torque. So the engine should deliver (using the above values) 18 ft*lb at 1800 rpm, 0.5 ft*lb at 300 rpm, and 1.4 ft*lb at 500 rpm.

Hope that helps.

Cheers...

stan
inverter motor

hi

i have a variable speed motor and i would like to control its speed electronically, does an ac control such as an inverter works?

any idea how should i go about doing it? do i select my motor first then the controller comes later?
wat specifications about the controller should i take note of?

thanks

stan