Re: Stepper power supplies, unregulated and Zener selection

Hi,

Wally, a 5W zener should do. The amount of energy returned is not
that great. Make sure the zener voltage is higher than the maximum
possible power supply voltage though. Do not use a series resistor.

Again, this is a concern only if ALL of the following apply:

1) Only one drive per supply
2) Large inertial load
3) High speed
4) Very rapid deceleration
5) Power supply voltage near 80VDC

You might want to look at the "Enery Dump Circuit" in the "Circuits"
file in the "Files" section of this group. This circuit senses
current direction and will dump returned energy to ground.

Mariss

--- In CAD_CAM_EDM_DRO@egroups.com, "Wally K" <cnc4me@u...> wrote:
> Mariss, in your white paper you recommend a zener across the power
> supply for the higher voltage supplys near 80VDC (yes people
actually
> read those things). This is to prevent charging the supply to high
> when steppers are decelerating.
>
> Do you have any advice on how to select this zeners wattage rating
> and would you put a resistor in series with it. Seems to me this
> zener power rating would be dependent on the size of the stepper
and
> the number of steppers on the supply. And of course sized for a
> worst case of all steppers decelerating at the same time.
>
>
> Wally K.