KBIC-240 DC SCR type speed control for sale. I can provide a photo if needed but it's a standard part. I removed this when I decided to go with PWM type spindle controllers. $75 includes shipping to anywhere in Canada. If you are going to use a spindle control like this with a Centroid Acorn you will need to purchase a signal isolator also. This units input signal is not electrically isolated. I think this controller is suitable for treadmill type motors but you will have to research the motor that you have. You will have to supply a current setting resistor if the one currently installed does not match your motor.
230 VAC input 180 VDC output
230 VAC input 180 VDC output