# Motor power: volts or watts?

8 years 8 months ago #29528366 by sd1074
I am using SDC2130.

I've looked through the manual (dev.roboteq.com/dev1/index.php/docman/mo...ers-user-manual/file) quite thoroughly, but there is one thing which is still not exactly clear to me.

The value throughout the manual referred to as "motor power": is it the voltage applied to a motor or the actual electric power (voltage*current) on the motor? I've found no clear statement in the manual specifying this.

8 years 8 months ago #29528367 by Griffin Baker
Replied by Griffin Baker on topic Motor power: volts or watts?
The motor power is the percentage of power applied across the motor output. If your supply going into the controller is say 12V, 10A, and your motor command is is +500. That would be 50% of the motor output. So the motor voltage is at 6V and the current that the motor is drawing is also around 6A.

8 years 8 months ago #29528368 by sd1074
Replied by sd1074 on topic Motor power: volts or watts?
Strictly speaking, in your example, the electric POWER applied to the motor is 6V*6A = 36Watts. If we assume the maximum power Pmax=12V*10A=120Watts, then it makes it 36/120=30% rather then 50%.

So even though you call it "power", I assume you actually mean VOLTAGE applied to the motor (average voltage after PWM) rather then POWER.

This terminology confuses me a little (I am not a native speaker). I used to think that "power" is electric power (en.wikipedia.org/wiki/Electric_power) as measured in watts, but it seems like "power" can also mean voltage.

With this motor controller then, if my battery is 12V, and I apply +500 (50%), then the voltage applied to the motor is 12V*50% = 6V, and Amps/Watts have nothing to do with this.

Correct?