Diy Brushless Spindle

[Jonathan]

Nowhere near as big as mine :)

What motor did you use...what power? Doesn't it accept more than 12v (assuming the battery charger you're using is 12v)?

A toroidal transformer (eBay) plus rectifier and some good low ESR caps would do nicely, but you might find it needs to be a bit large. Another option is a switching power supply ... which isn't cheap either unless you use old ATX (computer) power supplies. If it's 12V then just use one, if not you can put them in series - but check that they're isolated first to prevent fireworks.

My next spindle is going to have 2 or 3 motors 3kW motors on the same shaft, ER-20 up to 27000rpm (ish) and oil cooled. That's the only way I can work out to get the required rpm range and torque without rewinding (which I might need to do anyway). Wye/delta switching plus something else to get more torque options). Bought the motors a couple of days ago. Going to use FEA to model the friction due to oil cooling and optimise it ... then proceed.
Anyway, the relevant bit for you is I'm going to use 2 (or 4, depends) ATX PSUs in series, to get about 1kw input power, with a 3Ah Lipo battery placed in parallel, to take care of current peaks, as close as possible to the ESC (to minimise impedance). Will also replace the electrolytic capacitors on the ESC (which will be incorporated into the oil cooling) to an array of low impedance ones as that will make the ESC run a lot cooler.

Hope you're not milling with that chuck, or spinning it as fast as that motor might go.