Electronics > Power/Renewable Energy/EV's

Is this StepDown Transformer faulty?

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richard.cs:
Despite Vinlove's lack of country flag it is pretty clear to me that the transformer in his second photo is one of these: https://www.google.com/search?q=uk+power+tool+transformer.

These are connected internally as described here: https://electrical.theiet.org/wiring-matters/issues/62/reduced-low-voltage/ and the earth connects to both the centre tap of the secondary winding and the earth pin of the output connector(s), possibly also the transformer core.

What's not clear to me is what he's trying to do with the transformer.

vinlove:
Oh, I thought no one would come and answer this question, but here we are :) Thanks.

Well, the transformer was bought to power on Ham Radio, which is vintage from 1960s, all tube construction. Because it is made in USA, and imported, it must be run with AC 110V mains.

Here we have AC mains voltage 230V, so needed the step down transformer.  Yes, the converter socket had a pin at the wrong way, and it would not line up to the input socket's groove in the transformer.  So I Was going to return it, but then I have no time to browse and order another one, and wait for few days, and still am not sure if it will be the right one. So I cut the pin off with a saw of my multi tool, and it is fitted to the transformer. And I was reading the output with mains socket tester.

But it seems all working OK, because I connected and tried a few different items running on 110V such as electric shaver, and Laptop power supply etc.  They all functioned correctly without any sign of stress or going "Bang~".

vinlove:
I still have not powered on the ham radio with the transformer, because it is such as vintage, it needs a through clean up and rust removal on the input plug.  The input plug pins are covered in some rubbery stuff and is not conducting as is now. :(

richard.cs:
Electronics from the 1960s is often of a "live chassis" design where the chassis "ground" is not isolated from the mains supply and may be connected to Live, Neutral, or a rectifier output. These can be quite unsafe, and more so on some supply types than on others. Do you have schematics or other design information to confirm?

vinlove:
The radio must have been in use by previous owner for long time in Uk with a stepdown transformer.

I see it has usual uk mains plung attached, but marked as 110v only.

Also, the power supply must have had been serviced with new smoothing caps, because they are all new.
But the radio itself must have been left unused for long time which needs good clean especially the power input connector, tube sockets and pins, which are rusty and grimey.

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