Oh… din’t know Paul was SK. I bought a few tuned input boards from him a few
years ago. Great guy, great build. I’ll take a look in his gallery and see if
there are any comments. I know he proposes SSR in his control board, but no
reference to what types he uses.
K8RA also uses SSR:s in his handbook-build. But they are random fire. That
might Work better…
< I don't like solid state relays for this reason and others in this
application. I still use sealed 20 or 25 amp relays. Never had a failure
yet.>
I’ll probably end up there too. Now I just want to dig to the bottom of the
challenge and learn something on the way.
/ulf
Sent from Mail for Windows 10
From: Jim
Sent: den 9 januari 2019 02:29
To: amps@contesting.com
Subject: Re: [Amps] SSR in amp PS not working as expected
Hey Ulf....
The late Paul, WD7S, had issues with this too... Or was it was the late
Jerry, K8RA... I don't remember. Both great guys!
One of them had the same issue where they had to add a resistor across
the primary of the plate transformer to stop this exact thing.
Take a look at WD7S's site. It's till on line... You may find were has
pictures of the resistor across the transformer primary and an
explanation of why...
I don't like solid state relays for this reason and others in this
application. I still use sealed 20 or 25 amp relays. Never had a failure
yet.
Let us know.
73
Jim W7RY
Thanks
73
Jim W7RY
On 1/5/2019 4:59 AM, Ulf Tjerneld wrote:
> Hi All,
>
> I start with the question:
> Is there anything around SSR:s in general or anything in particular around
> the Crydom CSD2525P that I don’t’ understand when used as breakers and step
> -start in a HV PS?
>
> And the background:
> After a few years off the reflector and amp building I recently dusted off my
> big-ultimate-amp-project and took up the work again.
> This winter’s focus is the PS. I thought it could be nice to use SSR:s in the
> AC-circuit for breaking and step-start. I have never used SSR:s before, but I
> expected it to work as planned as I perceive them as pretty simple devices.
> Anyhow, I bought three surplus SSR:s off Ebay, Crydom CSD2525P rated at 25A,
> and built a standard breaking and step-start circuit around them.
> Everything was tested with a low voltage 230/12 Volt small transformer on the
> bench. It works as expected; the two SSR:S in the 230V line switches on and
> the third SSR shortens the inrush resistor after about a second of delay.
>
> But, when testing with the HV-transformer, it doesn’t work.
>
> The HV transformer is boxed in the chassis and disconnected from all
> secondary loads. The HV-output is isolated and off from anything in the
> circuit. I measure voltage on the 105 volt secondary winding. The only things
> outside of the box is the multimeter and the 12Volt DC control voltage. After
> applying control voltage the SSR:s in the AC line actuates and the
> transformer starts to hum, which it shouldn’t, and after a second the
> step-start SSR actuates and the transformer starts to hum loudly. The reading
> on the 105V secondary was close to zero.
>
> The transformer in itself is a custom made 2KVA toroid beast wound for me in
> Germany in 2013. With the breaking circuit out of the loop, the transformer
> is almost inaudible and delivers as expected in the 105V secondary,
>
> So, the question is: is there anything around SSR:s in general or anything in
> particular around the Crydom CSD2525P that I don’t’ understand? Please
> advise! 😊
>
> /73’s SM0NOR - Ulf
>
>
>
>
>
> Sent from Mail for Windows 10
>
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