High voltage diode blowing mysteriously

Well, then wind another one :-)

... and they can be bolted to a heat sink. But you said yours don't get hot so that's weird.

At 2.25W per diode these would get friggin' hot ... phssss ... OUCH! What is more dangerous is if you had current spikes into the 2-digit range which is only rated for non-repetitive.

Not for those kinds of voltages, and SiC is still expensive.

Tich tich, you little depraved monster you. I can't meet your twisted cuisine requirements. Have you tried a local abattoir? I hear bulk orders are available for those in your state.

mike

so it seems to be okay.

Coupled output inductors are useful, in reducing minimum load for quasi-regulated outputs - your -250V and 6V3 filament supply.

There are leakage effects that have some regulation benefits, but will almost guarantee conversion frequency doubled reverse bias spikes at turn-off - so a kilovolt diode has no margin here.

The negative rail, being quasi-regulated, will have the higher voltage when loading swings to the regulated rail.

RL

output (600p-p, not counting LL), and it's obviously full wave, not half = wave. The driver is clearly half bridge and the transformer ratio is = clearly 1:4+4.

very familiar indeed. Add some laggy parasitic C, and some springy LL, = and you've got the real thing. The only difference between this circuit = and the actual circuit is the center tap and split choke, which do not = affect the simulation results, and serve only to split the resulting DC = output in half, hence +/-250V.

And your line of thought goes to heck in a handbasket due to the inductor input filter! Put some capacitance right at the output of the bridge,

output; 3A heaters, fractional mA at -2kV, 100mA at +230V, 35mA at =

-230V). =A0It runs cool and smooth for about a minute (aside from the = snubbers, which get quite hot), then suddenly the output drops dead and = the current limit starts squealing. =A0One of the negative output diodes = is failing shorted. =A0(Good thing the current limit keeps it from nuking= the transistors.)

up from the snubbers). =A0The waveforms show 120V overshoot, which is = well within ratings (1000V diode with about 600V peak reverse). =A0I = can't imagine it's an avalanche thing, as the reverse voltage is low and,= until failure, the diodes run cool. =A0I'm still more confused that it's= consistently the negative side diode (three have died so far), which is = the lighter loaded side.

where

map

function.

You have a bit of hoof in mouth i see. CR was once used for Crystal Rectifier, a reflection of its solid state nature and variety of chemical compositions. Ever heard of copper oxide or selenium rectifiers?

where

of said snubbers.

diodes" or "FWB". I'll know exactly what you're referring to, just as = well as "D17-D20" or whatever.

I know you have heard to heard of LTSpice. Not too bad for schematic capture alone.

I owned a '66 Honda Dream in the early 70s.

The old bikes had Selenium rectifiers in 'em.

That was just the earliest exposure I had to them.

Hard to model multiple output winding transformers though.

Even with the 'real pro' sim packages, it is not a simple chore.

Nunya

it

format

creativity,

Nope None-yah. BTW I have been on Usenet since the time before "Big 8". Word wrap has always been a client issue, for good reason. If your client is too incompetent to handle long lines get a better client (or better user wetware).

Oh Great Whizzard, post some of your electronics "skill".

Tim

--=20 Deep Friar: a very philosophical monk. Website:

No, idiot, it has always been an nntp server issue, and the clients were supposed to be written to comply. Any client that does not is at fault, and it is on the authoring side where the line length limit gets imposed.

The fact that you are oblivious to it is a huge tell about you.

The fact that you think it is a mere reader application issue is an even bigger tell about your aptitude... err... extreme lack thereof.

Not a typo, idiot.

"Gotta find a woman..."

And "Right on..."

are lines from a famous song. For you to be absolutely oblivious to it tells me that you were just as blind back in the seventies as you are now. Here's another... "Hot Pants!"

Learn how to set your line length properly and you MIGHT get back a point or two of your pathetic IQ back. The thing is that it will take years. It is like fat. It will take you just as many years to extricate the stupidity you have accumulated over those years.

You are an idiot, right NOW.

IFYEMFY

(I Fixed Your E-Mail For You)

Bwuahahahahahahahahahahahaahaha!

Me? I prefer Galena crystals. My feline was greatly relieved when I started using a thin wire instead of cat's whiskers for the contact connection.

The ancients could even use a slightly bent double edge razor blade and a pin for rectification of radio waves.

mike

Why? Never had a problem with that.

I found LTSpice to be rather "pro" :-)