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Driving a 2A stepper motor

Posted by cearza 
Driving a 2A stepper motor
April 24, 2016 05:03PM
Can my A4988 step motor driver handle a motor that has a rated current of 2 amps?, It will be necessary to move the potentiometer to adjust the current limit for the new motor?
Re: Driving a 2A stepper motor
April 24, 2016 07:11PM
If you mean the A4988 on one of those little plug-in driver modules, you have absolutely no chance of running them at 2A. A4988 driver chips are designed to be cooled through the PCB, and those modules provide far too little PCB area to cool them properly.

OTOH you don't necessarily need to run the motor close to its full current. 3D printers typically run the motors at between 50% and 85% of rated current. So although a 2A motor rating is on the high side, you might get away with it.

Electronics with on-board drivers, such as Duet or Smoothieboard, provide much better cooling for the drivers and allow higher currents to be used.

Edited 1 time(s). Last edit at 04/24/2016 07:12PM by dc42.



Large delta printer [miscsolutions.wordpress.com], E3D tool changer, Robotdigg SCARA printer, Crane Quad and Ormerod

Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].
Re: Driving a 2A stepper motor
April 25, 2016 06:09AM
I use 2A motors and DRV8825's, and I could not run them at full, even with a huge fan blowing on them all the time. When I turn this fan on, it makes a draft that I can feel on the sofa while watching TV 10ft away....
I havn't got an enclosure around my electronics though, and this may aid the cool air onto the drivers better, and make me less cold.
Re: Driving a 2A stepper motor
April 25, 2016 01:30PM
As DC said, the plugin drivers suffer from inadequate pcb area to dissipate the heat. If they'd been designed the other way up, with the components on the underside, we'd have a better chance of getting the heatsink on the pcb and extracting heat that way, but as it is there's really not much that can be done.
Re: Driving a 2A stepper motor
April 25, 2016 05:23PM
There are some plug-in boards where the chip is installed on the bottom with a metal pad on the upper part for a heat sink. If you can find those they are much better than the typical cheap ones that are built incorrectly and you can actually use a heatsink/fan to push them harder.
Re: Driving a 2A stepper motor
April 26, 2016 01:00AM
Or the main board designers could put a copper clad .250" hole directly under the Pololu driver board and solder a copper cylinder in it to act as a heat sink.
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