Value of Zener diodes

Jon-

How is the value of the zener established? I am using a current
limiting power supply which operates at up to about 30 volts.

Grant

--- In CAD_CAM_EDM_DRO@yahoogroups.com, Jon Elson <elson@p...> wrote:
> A unipolar drive has
> several ways to deal with the voltage and current in the
"turned-off" half
> of the winding. The most common scheme is to have a freewheel diode
> that sends the current back into the power supply. This effectively
shorts
> out the winding, and a shorted winding changes current only slowly.
> To get faster charging of the winding, resistors, or Zener diodes can be
> put in series, so a large voltage is developed across the winding,
thereby
> draining the magnetic field quickly. This, however, burns substantial
> energy as heat every time the driver makes a step.
>
> Jon