Hello all,

I am getting very close to the completion of my new cnc router that i have been building for a couple months. Yesterday I finally started doing a test cut which was to surface my table so that is is true to the machine. Durring the cut my bit came loose, and I quickly hit the e-stop button and then poof my power supply for my spindle fried.

My spindle is of the DIY variety with a large RC airplane brushless motor. To power the motor I am using a Meanwell 350 watt 24volt power supply rated at 14 amps. I have been using this same setup for about 6 months now with no issues including stalling the motor to the point the speed control went into lock out and the power supply was fine. From my testing the most current i am using is around 8 amps durring a cut. On my old machine jthe power supply was not included in the e-stop loop and i would just turn the motor off at the speed control if there was a problem. My new setup uses a relay to cut the main power to the power supply when the e-stop is initiated. I suspect that this may have been what fried the power supply but i dont know enough about them to be sure.

Durring initial inspection of the blown power supply i found that the internal fuse was not blown. I did find several resisters (i think too black to really tell but they had an "R" on the board next to them) that were blown along with either a mossofet or a voltage reg, and another IC that had all blown.

I have a spare supply that i was going to wire up but i dont want to blow it again. should i move the relay to the dc side of the power supply, or keep it where it is? My plan is to install an inline fuse on the dc side just to make sure i do not over amp the power supply.

Thank you for the help