Re: [CAD_CAM_EDM_DRO] Motor Noise?

phil wrote:

> I'm using a router speed control with a small laminate style trimmer and since installing the speed controller I've got problems on my Z Axis with lost steps.
>
> If I remove the speed control then all works well.
>
> Any suggestions on how best to -
>
> a) reduce the noise from the speed controller and/or motor
> b) shield the steppers from the noise.

1. Mount the speed control close to the motor, cut all cables
short to reduce radiation.

2. If the speed controller is a box type thing, you may be able to open it
up and put some capacitors from both line input terminals to case ground.
If the controller is not in a metal box, you will have to put it into one.
If you go this route, find a good quality line filter box (these are the
things with the IEC plugs like on the back of a PC) but they have a
filter built into them. A common brand is Corcom. Mount one of
these in the box with a fitted hole and screws. Mount the speed
controller in the box and connect the power input to the controller
to the line filter box terminals. Most likely the RFI is being coupled
through the power lines from the controller to the PC, stepper drives,
etc. (If you don't have line filters on the power supply for the stepper
drives, it would be good to put them there, too.) Finally, don't ground
the router to the machine, insulate it if necessary (most are double
insulated anyway). Let the router be grounded by a 3-wire plug to
the speed control, then through that to the wall ground. This should
keep RFI out of the machine control.

Hope this helps,

Jon