Stepper drivers keep breaking.

hi, ive recently finished building a prusa i3 with an arduino/ramps setup running sprinter.

I've now broken 3 stepper drivers, all on the x axis. They always break midway through a print. The drivers have all had heatsinks on them and they have never run hot. After the second driver broke i tightened the x belt, greased the rods, and lowered the voltage from the power supply from 12.6 to 12.2v, but to no avail, in fact the first one lasted longer.

I dont think the steppers are genuine pololu's, just compatible versions. (ive attached an image)

Im completely confused by this. I guess a last resort would be to buy a new RAMPS board. Any help would be really appreciated. thanks.

A stepper driver should not break because of a problem on the mechanical side of your machine. I would question if there is maybe a short somewhere in the cables of your stepper motor that only gets activated after the Z-axis does a move, which causes the X-motor to move up because it's on the Z-axis and that it would cause the cable to move and short-circuit.

It could indeed also be a bad connection on the Ramps, but that would be a different story that I'm not so familiar with.

The driver has built-in protection against over-current due to mechanical reasons. It was made to shut down if the stepper get stuck. If you are cooking the driver, its purely electrical.

That heatsink is quite large. Are you sure that it's not shorting anything. I actually run a Prusa2 without heatsinks and fans on the x, y, z and e Pololu stepper controllers. The one for the e was getting quite hot so I replaced it with the Panucatt Surestepper SD8825. The Sd8825 has much better heat management and the chip can handle much higher current and it can go to 1/32 microsteps.

Are you sure they are broken? Did the smoke escape?

Or did they just shut down and need time to recover?

Do they always "break" at the same physical location?

...R

I installed my heatsinks like this

http://www.shadowram.ca/?p=83

There's too much risk during installation that the heatsink may make contact with other parts of the board.

I run some 2A NEMA 23's off these without issue.

Edited 1 time(s). Last edit at 02/03/2014 01:05PM by ShadowRam.