# Motor dummy load resistor calculator

1. ## Motor dummy load resistor calculator

I am developing a test rig for my motor controller.

Below is the image which shows a motor is connected back to back to act as a load with load resistor

left side is the controller that will run the motor of 400W.

Right side i am connecting another motor with a coupling in between and resistor R1, R2, R3 at the end as dummy load.

Voltage generated on right side motor is 24V (back emf)

what vale of resistor R1, R2, R3 should I use to act as load of 400W at 100% pwm by the controller ?.

I saw a resistor of 200W 50ohm.

using three in parallel resistor values will be 16.5ohm

using I = V/R, 24V/16.5ohm = 1.4545A

power = 24V X 1.4545A = 34.9W (am I generating only 34.9W of load?).

Will this resistor value will work ? as 200W X 3 = 600W.

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2. ## Re: Motor dummy load resistor calculator

What type of motor is the motor which is electrically loaded?

Is it a BLDC or separately excited synchronous motor?

If it is an induction motor, it will not self generate back EMF.

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3. ## Re: Motor dummy load resistor calculator

Both the motors are BLDC.

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