Hi, I run an eShapeoko, set up for cutting balsa sheets for model boat kits. All I needed for a spindle motor was a small Johnson 12v can motor and a brass 3.2mm collet set - which worked fine.

Then I needed to cut some aluminium, and wanted to raise the capability a bit - so I bought one of the cheap 775 motors with an E11 collet that you can find on eBay. This would cut 1/8" aluminium fine once I found the right alloy for CNC machining. But it's a bit powerful for standard light balsa use, and I thought about using dynamic braking to cut the speed rapidly when I turned off.

At this point I have a question. Can I just short the motor leads? How much energy will this dump into the windings if I am running at full tilt (16,300rpm)? Do I need to connect through a braking resistor? And if so, what value should it have?

If anyone out there has addressed this question before, I would be glad to hear of their experiences....