Kress diy speed control

Mostly Printed CNC - MPCNC Advice
1

Kress 800 is in the mail from the UK, any thoughts on this for lowering speed? http://electronics-diy.com/1000w-ac-motor-speed-controller.php (many on ebay pre-made for cheap)

Looks like it keeps load constant , per description “when the motor of the drill machine is slowed down by the resistance of the drilled object, the counter-EMF of the motor also decreases. This results to a voltage increase in R2-P1 and C3 causing the triac to be triggered earlier and the speed increases accordingly.”

I know “Super-PID” is awesome but WAY over my (ok, my wife’s) budget.

2

Doesn’t the Kress 800 already come with build in speed control from 10000 to 30000 rpm?

3

FX…you are correct. The goal is to bypass built in speed control and be able to go lower than 10,000 (say for aluminum) and maintain torque. Looks like the gentleman at cnczone had an open source thread on a diy one. http://www.cnczone.com/forums/open-source-controller-boards/147042-open-source-atmel-arduino-pid-motor-control.html

4

I see, sounds like an interesting project. Let us know how it goes. How low do you need to go for aluminum?

5

It can be cut at high speed but lower speed can help with other kinds of material and less tool wear.

6

Hi…I have a SuperPID waiting to be installed, but have not done so yet as there were other problems with the machine, they have now been sorted.
The SuperPID uses an optical sensor mounted in the case of the router. There is room as the existing speed control is removed. This means that the spindle must always be used with the superPID as otherwise all nasty things will happen, like overspeed and burn-out.