Odd Power Transformer

[mikewh]

Has anyone run across something like this? Just struck me as odd. I can't find a schematic of it, but this is how it was wired in a Conrac 9" Monitor and was something that I was looking at using as a bench/test supply.

The primary seems to have 2 sets of primary windings 120volts:
1 Black and red/black reading approx 6.5 ohms
2 Blue and Blue/Yellow reading approx 6.75 ohms
The primaries were wired in parallel.

Secondaries are as follows:
HT Secondary
Red start, Red/yellow C/T, Red finish
60 volts Red to Red and approx 1 ohm
Start to C/T .5 ohm and 30 volts
Finish to C/T .5 ohm and 30 volts

LV Secondary
Orange and Orange approx .2 ohm and 6.3 volts

All tested with no load out of circuit.

Are the dual primaries for rewiring for european voltages?

Thanks!
Mike

[daschnoz]

Exactly. With 110 primaries, they get wired in paralell as you stated they are. At 220, they get wired in series. You have to watch the phasing in the series connection, hence the trace colors on the leads.

Since you're in the states, it sounds like you have a good isolation transformer. On the secondary, don't connect the C/T. Connect the red leads to a bridge rectifier. Add a filter cap, and you're looking at about 170VDC. It's gotta be good for something.

[mikewh]

Thanks! That's what I suspected I was just having a time of it trying to find reference to that sort of layout and the color codes.

Thanks!
Mike