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Two stepper drivers burned already!
Posted: Tue Sep 29, 2015 6:19 am
by nalmeida
Hi there, I've been very pleased with my LittleRP and have been printing a few objects with great detail. The only problem I found until now is that I already burned two stepper drivers! I use the A4988 ones and everything works great except when connecting/turning on, on two occasions the stepper driver simply burned. Is there a correct way to connect the machine? The motor is always connected and then I usually connect the power and the usb randomly, should I obey an order on these two? Is there something else that might be causing it? I already checked voltage, rechecked the soldering and now I'm just praying that the third A4988 survives!
Re: Two stepper drivers burned already!
Posted: Tue Sep 29, 2015 12:02 pm
by goopyplastic
Hrmmm, the main issue is just removing either of the motor cables while the shield psu is attached. Shouldn't be an issue which order the usb / psu are attached however usb first is probably better just to avoid motor jittering while the arduino boots up.
Are you adjusting the vref potentiometer on the allegro drivers? They may be set too high by default. The motors are rated at 1.2amp but you can try setting an amperage of 1amp on the drivers. They shouldn't be more than on the high end of warm by the touch. It's possible that they are burning up from too much heat / too high of an amperage. DRV8825's are less likely to cook.
Re: Two stepper drivers burned already!
Posted: Thu Oct 01, 2015 3:41 pm
by Scatterplot
Be sure to check your connections- if you have a loose one, it could cause the same symptoms as the motor being connected/disconnected under load.
Re: Two stepper drivers burned already!
Posted: Mon Feb 22, 2016 10:28 am
by DanOrgan
Anyone tried DRV8825 drivers?
SD8825 is hard to find, I am looking for an alternative.
But connections for those drivers are slightly different:
The SureStepr SD has VDD connector and Pololu DRV has Fault connector on its place.
Re: Two stepper drivers burned already!
Posted: Tue Feb 23, 2016 3:43 am
by radi2k
Check that the motor current is properly adjusted!
A good explanation is on this page:
https://www.pololu.com/product/1182Sub-section "Current limiting".
Re: Two stepper drivers burned already!
Posted: Wed Feb 24, 2016 7:19 pm
by goopyplastic
I find that setting .5v vref is pretty safe, we have enough torque that we don't need to go to the 1.2 amp setting. The chips tend to run pretty cool at 1amp, even going down to .8amp is fine.
I also noticed that polulu sends drv's set for 3+ amps stock ... which causes problems as you might guess
