STEP UP Transformers

[4krow]

In my never ending need to disassemble evaluate and modify existing products used in my system, I have discovered something unusual. I have a Cayin CD player that uses 220V. Of course, the simple solution was to buy a step up transformer. I did that years ago, but the bug got me again, so I disassembled it to look for 'errors'. That's when I found that this tranny had several input taps(I knew that from the input voltage selector). Ok so far, BUT the secondary only has one winding on it's side of the transformer. Strange. From what I can tell, one side of the incoming AC is routed to the output outlet, and it is split, also going to the primary side of the tranny. Ok, but why wouldn't BOTH sides of the input wires go directly to the primary windings? Stranger yet is that when connected to a balanced AC line, one side reads 160V and the other only 60V, which helped me determined that only ONE side is using the tranny winding. To HELL with that, and I just ordered another tranny that makes more sense to me, especially when using a balanced AC input.

[Paul Birkeland]

That's when I found that this tranny had several input taps[...] the secondary only has one winding on it's side of the transformer. [...] one side of the incoming AC is routed to the output outlet, and it is split, also going to the primary side of the tranny [...] when connected to a balanced AC line, one side reads 160V and the other only 60V

The secondary should only have one winding, why would it have two?

The neutral (usually) of the incoming power will go to one end of the primary and could go to the secondary (observing phase).  This connection would be common for a step-up transformer not designed to be an isolation transformer.

When you say one side reads 60V and the other 160 when connected to your balanced power, can you be a little more specific?  Are you feeding 120V balanced power to the primaries, then seeing on the secondary?  Are the ground and neutral tied together in the step-up?  How does this transformer work without your balanced power setup?

[4krow]

Well, wouldn't you know it, I misstated the secondary winding thing. I should have said that secondary side of the transformer only has ONE WIRE coming out of it. I am assuming that one of the wires on the primary side of the transformer is  actually the other side of this secondary winding(clear as mud now?) Skipping ahead, the device worked ok whether it was using normal AC or balanced, but the voltage readings were quite strange when fed by a balanced source. The ground is not tied to earth ground. Having said all of that, let me save you the trouble of further analysis by telling you I made a little mistake(I think it was Freudian in nature, meaning I really just wanted a new device) by miss-wiring something else in the circuit, and the tranny is no more. I have ordered something that looks to be much better quality, with no extra innards(MOV's, etc.). I will place it in an attractive cigar box and call it 'all good'. Thanks for the interest anyway, as I am sure to 'inspect the next victum' this time with photos for clarity.

[Paul Birkeland]

It wasn't a transformer, it was an autoformer...