# finding RPM of stepper motor

Discussion in 'The Projects Forum' started by venkatesh.n.s, Jul 17, 2014.

1. ### venkatesh.n.s Thread Starter New Member

Jul 17, 2014
1
0
Hi this is venkatesh

how to calculate the speed of stepper motor when the pulse width is known. for a motor of 1600 pulses/revolution and a step angle of 1.8 deg
what will be the speed if the pulse width supplied is 170 microsecond.

2. ### ericgibbs AAC Fanatic!

Jan 29, 2010
2,581
389
hi ven,

Assuming 360 deg /revolution and a 1.8deg step thats 200 steps/rev.

Also assuming a pulse ON period of 170uS and an OFF period of 170uSec.
Thats 340uS which is a frequency of ~2940 . So 2940/200 = ~15rpm.
for a two pole stepper.

Do you have a datasheet for your motor that you could post.?
E

3. ### Alec_t AAC Fanatic!

Sep 17, 2013
5,967
1,135
I'm getting a different answer. If we assume 170uS on/ 170us off, then the time for one rev is 1600 x 340uS = 0.544 sec. So rpm = 60/0.544 = 110.3.

Edit: What we really need to know is the pulse period, rather than pulse width.