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Re: ID these transformers?

1/16/2005 8:59 PM
Re: ID these transformers?
Well, they could be tapped inductors, but I think they are autotransformers for some use. I recall some old Seeburg Jukebox wall boxes - the little things at each booth in a diner so you could select tunes without going over to the jukebx itself.  
In the cable that powered it, each wallbox got 24VAC. The relays and stuff ran on that, but there were 6V bulbs and stuff. So there was a small autotransformer inside that stepped the 24 down to 6 for them.  
An autotransformer is just like a plain transformer, but it only uses one winding. A tap is placed on one point in the center and the ratio decides the voltages. It can be used to step up or down. A 24/6 type can be run backwards to make 24v when you have only 6v.  
I and others use that trick to run a small one tube circuit from a 6VAC adaptor. RUn 6VAC into the unit for heaters, then run a 6V transformer backwards to make 120VAC which can be rectified or doubled for the plates. I don't use an autotransformer because I need isolation, but I could.  
That is my guess.

MKB Another modern use for autotransfor... -- 1/17/2005 6:59 AM