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mhennessy · 29th Dec 2018, 7:47 pm

Well, don't take my word for it; do the experiment

I've got a couple of 500VA transformers here that take about the same current. I think that's normal for the breed, sadly. As they are only used intermittently*, it's not a big problem. However, I wouldn't want to use them to run isolated bench outputs on a full-time basis (something that some favour) because that would just waste energy and the noise would drive me mad.

*: As isolation transformers are only needed to allow the safe connection of earthed test gear to the "live" parts of a DUT, it follows that most of the time, they are unnecessary - so only use them them absolutely required, and rely on the RCD for the rest of the time.

Here's another question:

Have you figured out how many radios you can safely power from your 500VA isolation transformer?

29th Dec 2018, 7:47 pm	#14
mhennessy Dekatron Join Date: Jul 2007 Location: Evesham, Worcestershire, UK. Posts: 4,244	Re: Variac first or Isolation first ? Well, don't take my word for it; do the experiment I've got a couple of 500VA transformers here that take about the same current. I think that's normal for the breed, sadly. As they are only used intermittently, it's not a big problem. However, I wouldn't want to use them to run isolated bench outputs on a full-time basis (something that some favour) because that would just waste energy and the noise would drive me mad. : As isolation transformers are only needed to allow the safe connection of earthed test gear to the "live" parts of a DUT, it follows that most of the time, they are unnecessary - so only use them them absolutely required, and rely on the RCD for the rest of the time. Here's another question: Have you figured out how many radios you can safely power from your 500VA isolation transformer?