I bought the A4WD1-KT kit. They came with four GHM-14. Before I built the kit, I wanted to test out the motors, so I hooked them up to my power supply. When I turned it on, the motor instantly draws nearly 3 amps and doesn’t move. This was the case with all four motors. Thinking it was something I did wrong, I put the motors to the side and bought some more motors.
I got 4 PGHM-01 motors. When I tested them just like the GHM-14 motors, they worked fine.
I also found 4 other motors I had purchased previously from Lynxmotion and tested them. They all worked fine.
So, I went back to test the GHM-14 motors again. And, they still aren’t working. All I’m doing is connecting voltage from the power supply to the leads.
Im just curious, have you tried turning the output shaft a tiny little bit, and seeing if the motors continue to turn after that point? I am not an expert on DC motors, but I have had one or two of my 540 size motors lock up because of weird things with the brushes and commuters.
Also, have you tried taking the gear case off, and seeing if the motor by itself turns?
Just grab the shaft and gently roll them over with pliers. they are probably just sticky and stuck in one spot. Once they break loose, they should be fine.
With motor disconnected from power, rotate shaft with pliers in both directions a few times
Connect to power.
Shaft then sits there and motor draws 2.5 amps.
Next,
With motor connected to power and drawing 2.5 amps, turn shaft a hair with plies.
Motor now turns regularly. But, it will never start turning on it’s own. I always have to use pliers and turn the shaft a hair then it will take off. This happens in both directions and with all 4 motors.
Seems really strange doesn’t it? Did I just get a bad batch of motors?
I strongle suspect your current meter is inaccurate and/or your supply is not capable of delivering the required startup current. Like I said 0 returns on the motors. I do not suspect you have received any defective items.
Hearing this, I would certainly say power supply as well. This can happen if the brushes are binding because they are not seating or if there are metal filings int he motor but like Jim said, there’s never been a problem like that. And to get 4 that aren’t working at once, it must be something on your end.
Try a different power source. What are you using now?
Another test would be to connect a volt meter across the motor power leads and check the power supply voltage. Then connect the power leads to the motor and see how much the voltage drops. If it is more than a couple of volts, the power supply is probably too small.
One other quick check: put some allagator leads on the motor, and then take it outside and connect it across the 12v battery in your car/truck and see if it runs.
Another suggestion is to buy Battery pack from Lynxmotion and use it as the power source, your gona need one anyway so you may as well get one. Also pick up a charger to go with the battery.
That’s what I thought too, that’s why I bought more motors. I figured I’d see what happens with those.
You’re right! It works great off a battery! I already have batteries of course so I should have just used those. My power supply says it can deliver up to 3 amps, so I guess these motors take more than 3 amps to start them up! Seems pretty high, but they are good motors too.
Thanks for all the help everyone. This is why I like this store so much.
