I got the impression he wanted to short the ht out to make it safe though.
Another thing to ask is is the load inductive? When I could see Ive welded
many a rely like this!

I guess for the crobar effect one could use a semiconductor, and maybe one
the other way around so to speak to do the soft rise in voltage. Its a
highish current, but not impossible.

Brian

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"David Looser" wrote in message
...
"Ian Bell" wrote in message
...
I am trying to select a relay for a delayed HT switch (which will also
discharge the HT when off). Most relays I can find have contacts rated at
250VAC which translates into a peak of about 350V. However, data is scarce
on what dc voltage these relays can switch. So far I have found only one
that gives a dc current versus voltage curve and that stops at 210V dc
(and 200mA) and I really want to be able to switch up to 350V at up to
200mA. The rest just give a dc voltage at max current value.

So, I am guessing that this problem has been faced before and there are
relays that are known to work fine in this application. Any
recommendations?

By the way I prefer a 5V coil.


The ratings of relays (indeed switches generally) is lower with DC than
AC. The usual general purpose relays available these days are rated to
250Vac, but often only about 30Vdc at rated current. You could use a
separate heater transformer and use the relay to switch the primary of the
HT transformer.

David.