Pololu GearMotor with Encoder operating Voltage/Current

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1

Hi,
I am using the Pololu TreX dual motor Controller [pololu.com/product/777] to drive Pololu34:1 Metal Gearmotor with 48 CPR Encoder [pololu.com/product/2273]

The intended voltage for the motors is specified as 6V but the operation range is 3-9V. The TreX driver supplies ~3.3V to drive the motors. Will the 3.3V operation voltage affect the motor performance in any way?

I am using serial commands to control the velocity. For the same velocity command given to left and right motors, the current consumption is different for both sides (current value acquired using external resistor in series). Is it expected behaviour ?
Example : for set left and right motor to velocity 30(decimal), I get current values 400mA and 300mA respectively.

Thanks,
Rupesh

2

Hello, Rupesh.

Motor parameters such as RPM and torque vary proportionally with voltage. At a lower voltage the motor will be slower and have less torque. When you say the TReX supplies ~3.3 V, is that effective voltage based on the duty cycle? You should make sure you are supplying the TReX within its operating voltage of 6 V to 16 V.

In regards to the variance in current draw you are observing, it is not unusual for there to be operating variances between DC motors of the same model.

- Grant

3

Thanks Grant !
That cleared my misconceptions about Current and speed dependence.