In article ,
Grunff wrote:

I need a variable speed mains AC motor for a project I'm working
on. Ideally, I'd like to be able to vary the speed using a
variac. It needs to go up to ~4000 RPM, which is beyond most
mains drills. Any ideas on where I can get one, or what bits of
equipment I can cannibalise?

The motor in our Hoover w/m looks a serious bit of kit.
1-2 HP, integrated speed sensor, smooth closed-loop
electronic speed control, in either direction.
The pulley ratio suggests that, at 1200rpm on the
drum, the motor shaft must be doing over 6000rpm.

But you need a circuit diagram to see how to wire
one up.

--
Tony Williams.