3-amp motor controller question(s)

Hello, I am considering ordering one of these 3 amp motor controllers but wanted to ask a couple things about it.

First, I want to use a pair of gear motors, 12v DC each at 60mA no load. Can I connect both motors to the controller board safely at once as to allow them to “share” the signal? (operate identically)

And second, I am using a Pololu mini serial servo controller, can I just connect the serial out of it to the serial in of the 3 amp motor controller?

thanks in advance, I am learning a great deal about electronics, mechanics and programming because of this site!


A no load rating isn’t really helpful unless you plan on using your motors with no load. Under load, motors can draw over 100 times the no-load current. This is especially important in a servo system, where the motor is almost always operated close to the stall point. However, many small motors do not draw much current, so it is entirely possible that you can run two of your motors off of the SMC03 motor controller.

Connecting the serial out from the servo controller to the motor controller serial input can work, but it’s better to connect the serial in lines. If you’re using an RS-232 serial source, the converted, logic-level signal is what appears on the logic-level serial in pin. If you’re using a microcontroller, just wire the same serial signal to both the servo controller (serial in pin) and motor controller.

- Jan

Thanks Jan- I was thinking the same thing reqarding the “no load” specs- the website could be more descriptive. Heres a link to it, I will probably just do a trial and error scenario:)

batteryspace.com/index.asp?P … rodID=1157

I can’t tell much from the page, either, but I suspect that you should be fine, even with the two motors per controller. One option I forgot to mention is putting the motors in series. In the discussion so far, I’ve been assuming hooking up the motors in parallel, but if they draw too much, you can put them in series.

- Jan