What good is a thermistor on a solid state rectifier?

The sl15 60002 thermistor weber uses in the ws1T is rated for 115-230 ac
Nowhere in the ss rectifier are thoes voltages. It would be an instant rush. No?
(St120 with time delay relay authenticap 550v quad) the only thing I think the thermistor would do is gradually charge the quad but with 500dc, there's no gradually. Right?
Would a gradual cap charge be beneficial?
I'm running a variac at 113bto keep b+ at pcb at 420v

I have a ST-120 with TDR and use the Weber WS-1 w/thermistor.

After the TDR comes on, the thermistor results in a ~1 minute ramp to full voltage — in fact I question the need for the TDR if you always use a rectifier with a thermistor or of course a tube rectifier.

One time when I tried to pull the WS-1 out, the copper cap came off, so I took the opportunity to look at the parts….mine has a thermistor labeled 100D-11.
When I looked up the specs, there’s nothing I see about voltage; of course the only thing that matters is resistance, amperage rating, etc.

Anyway, don’t fuss over the WS-1 spec, just know that it work as intended even after 3+ years.  Easily repaired if needed, parts are inexpensive.  Not hard to totally make your own.

Thanks. Yes I've made my own as well. Weber says sl15 60002 is used. There is no delay. As soon as HV hits pin 4 and 6, pin 8 instantly hits 525 and settles at 500. I was expecting atleast a little ramp up. Weber says a few seconds but my meters say different.

I'm going to post a vid in a few hours of the pin 8 action.

As I said, mine does have a delay, ~1 minute.  Measured with Fluke DMM.

Are you measuring when connected to the cap(s) and to the tubes?  If not loaded, the result will look instant.

I don’t know if Weber changed the thermistor or not since I bought mine, but if it doesn’t have a delay then it’s not worth buying — it isn’t performing.  Might as well buy something a lot cheaper with just diodes.

I belive you. Probably changed design. Amp is all loaded.

https://youtu.be/-rvKWX8wbi4
Video of voltage test with ss weber ws1t

StevieRay wrote:I have a ST-120 with TDR and use the Weber WS-1 w/thermistor.

After the TDR comes on, the thermistor results in a ~1 minute ramp to full voltage — in fact I question the need for the TDR if you always use a rectifier with a thermistor or of course a tube rectifier.

One time when I tried to pull the WS-1 out, the copper cap came off, so I took the opportunity to look at the parts….mine has a thermistor labeled 100D-11.
When I looked up the specs, there’s nothing I see about voltage; of course the only thing that matters is resistance, amperage rating, etc.

Anyway, don’t fuss over the WS-1 spec, just know that it work as intended even after 3+ years.  Easily repaired if needed, parts are inexpensive.  Not hard to totally make your own.

So theres one thermistor in your ws1t? I assume its after the diodes and before pin 8? I just can't see a thermistor that's rated for 120-240ac, work well with 500vdc. Maybe if there are one per ac leg on 4 and 6 then hitting the diodes then landing on 8.

"You don't have enough current for a thermistor to be able to achieve what you want. Basically, the thermistors are acting as high-wattage resistors. If you did have the amps for the thermistor to work as intended. I believe the ramp will still be faster than what you want, probably faster than 500 ms"