Damaged metal gearmotor HP 6V


I purchased 4 of the same 20.4:1 metal gearmotor 25Dx50L mm HP 6V(item # 1572). When I try to do a simple test by connecting the motors to a 6 V power supply(Uniroi UC3010) none of the motors spin and my power supply shuts down implying there is a short circuit happening. I believe the motors came defected but I could be wrong. Can anyone help figure what’s going on?


We test every unit, so I suspect this is just a problem with how you are using your power supply. What do you have the current limit set to?

- Patrick

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Yes it was a current issue, I fixed the current on the power supply and it draws about 3 amps to get the motor to spin. Now when I connect it to the motor controller( TB9051FTG Single Brushed DC Motor Driver Carrier) it doesn’t spin the motor mentioned earlier. I’m assuming it’s a current issue. If this motor driver doesn’t work for this motor can you suggest one that does?

The TB9051FTG should be okay for powering that motor (especially if there is no load on the motor yet). Does your motor driver work if you test it without the motor connected (i.e. do you see a voltage difference between the outputs when expected)? Can you post more details about how you are trying to use the driver and some pictures of your setup, including ones that show all of your connections and both sides of the board?

- Patrick

The motor driver works, I connected a non pololu motor(lower rpms) and it runs fine but when I connect the HP pololu motor I get issues and doesn’t spin. I know the circuit connections are correct since it works with a different motor. The components I’m using is an arduino nano, step up voltage( 5V to 6V from arduino), motor driver, and motor. Could it be that the arduino nano doesn’t draw enough amps to the motor?

Your Arduino’s 5V pin is definitely not appropriate for powering motors (I am surprised that even your lower power motor worked at all), so you need some other power supply in your system other than your USB connection. You might consider powering your motor driver using the Uniroi power supply you mentioned earlier. Just make sure that all of the components in your system share a common ground.

- Patrick

Sounds good thank you Patrick! Also I have another question that a little out of this topic. I want to ask you if you can recommend me a 12V Dc motor that can pull at least 3 pounds and decently fast?

I would need more information to offer a specific recommendation. In particular, how much torque would the motor need to be able to apply, and what is “decently fast” for your application? If you are not sure how to determine how much torque you need, reading this “Force and torque” blog post might be a good place to start.

- Patrick

Thank you for the force and torque suggestion, it helped refresh my memory on torque! So based of my calculations if I use a spool with a radius of 2 inches to spool up/down at most 3 pounds I’ll need 96 oz-in torque, but the blog also said that it’s suggested to use 30% max stall load so then I’ll need 320 oz-in torque.

That seems like a reasonable estimate for the motor’s minimum stall torque. For that amount of torque you might consider our 37D gearmotors, and some of our highest gear ratio 25D gearmotors might be options too. If you know how fast you need the motor to rotate under load, that will narrow your selection down further.

- Patrick