Dazed and Confused greeting from Nottingham

[Doddy]

Ignoring everything else but to try to offer some advice on the spindle speed control and the question that you asked. Your controller board will very likely offer a 0-10V output that is intended to control the spindle speed. You can usually configure the controller with either 1 or 2 outputs to control the forward/reverse direction.

Now, looking at the eBay options that sort of hit your target. There's a number of ER11 collet 500W motors - typically air cooled and some with, some without spindle controllers. There's a much more interesting bundle of a BLDC motor - 500W but ER16 collets with speed controller.

Firstly - I would look to buy the spindle bundled with a spindle speed controller - it avoids one complication of ensuring that they work together. Spindles look to hit around £40 or £80 with controller.

Now, there's a number of open-framed spindle controllers on eBay, typically with a potentiometer for the speed control. Normally this would be where the 0-10V control steps in - the controller typically giving a 0V/10V reference and the potentiometer wired between these and a 0-10V speed controller input. But, here's the rub - particularly with DC motor speed controllers and those directly powered from the mains (as some of these are) - the spindle speed control input is not always isolated from the mains - which means that you have to be damned careful how to wire this to the motion-control card (and how you may need to pay care to the wiring to avoid a shock hazard). The problem is - the couple of adverts I've read don't make it clear if the spindle-speed control input is isolated from the mains, or not.

With that being unclear, what next interests me is the similarly priced BLDC motor and controller with a ER16 collet for around £80 - about the same as the open-cage controllers, but...

These are designed to take a 50V DC input - which would be the same as your stepper PSU (just means a bigger transformer to drive both). But, the BLDC spindle has a couple of advantages over the traditional DC motor:
* The controller has a specific 0-10V input voltage range for speed control. This will be compatible with your motion controller board,
* The BLDC motor, by design, is a synchronous motor (it's actually a 3-phase AC motor) - and that allows a more controllable speed setting (the driver generates the 3-phase supply to the motor that rotates according to the 3 phase frequency, compared with a standard DC motor that rotates as a function of current (ne. voltage) and load.
* That also improves the low-speed torque.
* The DLDC controller supports FWD/REV control, unlike the cheap open-frame controllers.
* The ER16 collet is more flexible that the smaller ER11.
* BLDC don't have brushes - less audible and electrical noise, and less maintenance.


You *could* go the full hog and get a 2.2kW water cooled spindle, but that's not what you asked.