Re: Gecko wiring question

--- In CAD_CAM_EDM_DRO@yahoogroups.com, "Mariss Freimanis
<mariss92705@y...>" <mariss92705@y...> wrote:

> Ron,
>
> It's a 100V zener in series with a sub-100 Ohm,
> 1/10W film resistor. A few volts over 100V, the
> resistor blows open. You can't see it to look at
> it but an Ohmmeter tells the story. Works for reversed
> power supply leads as well, lets you know someone did
> something bad to the drive.
>
> Mariss
>

Very clever! What's the tolerance on the zener?
Does the R blow on millisecond transients, or does
it take a sizable fraction of a second?

I've always had trouble getting pulse power
handling info from the makers of film resistors.
Large IGBT gate resistors are ~1-4 ohms, and see
pulse currents of 5-20A (100-400W) for 50-100nS
at a 4KHz rep rate. Average power is usually
under 1W. I've used series/parallel arrays of
10 ohm 1206 film resistors for low inductance.

John Kasunich