[Amps] SSR in amp PS not working as expected

[David G4FTC]

Hi All,

Having been caught on more than one occasion with fakes, particularly fake SD memory cards, I now only buy semiconductor components from reputable sources - more costly, yes, but you are guaranteed a known product fully traceable to the manufacturer.

Coming back to the Ulf's SSR problem, I noted the reports of the transformer humming loudly - my first thought was that the SSR was acting like a diode - only half the a.c. waveform was being fed to the transformer. Replacing the transformer with a resistor and observing the waveform with a scope would confirm or deny that prognosis.

David G4FTC
________________________________
From: Manfred Mornhinweg <manfred at ludens.cl>
Sent: 09 January 2019 15:22
To: Ulf Tjerneld; g4ftc at hotmail.com
Cc: amps at contesting.com
Subject: Re: [Amps] SSR in amp PS not working as expected

Ulf, David,

> I did a google search for the Crydom CSD2525P SSR but I can't find
> any datasheet - could it be a "special" for some particular
> application and is incompatible with what you are trying to do?

Indeed - I couldn't find a datasheet either! The closest seems to be the
CSW2425, which is a snubberless, zero-crossing triggering, antiparallel
SCR SSR. Snubberless is definitely not the right kind to use here, and
zero-crossing triggering also leads to more trouble than advantages when
controlling transformers.

But that's for the CSW2425, not what you have...

Ulf, maybe you got a Chinese "eBay special" devices - which means fakes!
  In that case nobody can tell what's really inside your little black
boxes. There are quite a few crooks in China re-labeling ultra cheap or
defective parts to look like more expensive, famous-branded ones. But
the practice seems to be getting less common. Lately almost all parts I
have ordered from China were real. Emphasis on "almost".

Manfred


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