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Exploding CAPS again, brand new CNC driver board goes BANG. (but will be replaced)

I have been working on my CNC milling machine and tested the new stepper motor controllers last Friday 13th.

Brand new controller, power supply made of a large toroidal transformer, large diode bridge and lots of parallel capacitors made a very strong 42 volt.

After the smoke cleared... I investigated the source of the problem. This was not a fault I made in wiring, nope...

The exploded capacitors were 220uF/16 Volt types parallel to the power supply of 42 volt...

Not a real surprise that they did not last 2 seconds.
I do not think it is very hard to build a good CNC stepper board, but some engineers or buying departments still struggle with the basics like capacitor voltage specification.

After removing the exploded capacitors we managed to get the motor controller working without problems (without the caps) The CNC machine now moves all Axis fine, runs smooth in 1/2 step mode controlled by an Arduino with GRBL software (for now, maybe later I will try LinuxCNC)

UPDATE: 26 feb 2015

I have contacted OMC stepper by email, sent a few pictures and explained my issues.
They have investigated promptly and confirmed the problem with a number of boards, the caps were of wrong voltage specification. They are investigating how this has happened, but the problem will be taken care of, and I will receive a new board.

UPDATE 2 mrt 2015

I have received a new stepper controller board replacement from OMC stepper.
The board has different Caps, not the 16V 220uF but 50V 47uF.
That will work.


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