Zenith Power Transformer Connections

[zeno]

I dont remember the name but its a special transformer
that uses an oil fill cap across one of the windings for
regulation. All Zenith colors used it from E-line through K
line. IIRC without the cap the transformer will pulsate.
I can dig tomorrow for the manual & give you the color codes.

73 Zeno

[rca2000]

Several names for it. Constant voltage transformer. Ferro-resonant transformer. Voltage regulating transformer. ALL mean the same thing. A transformer which uses forced core saturation to hold the output voltage steady..regardless of load or line changes(within reason of course). That oil cap is across the main secondary winding and tunes the winding in some way--without it--it will NOT regulate right and ALL voltages out of it will be quite low.

I would say the primary winding will be around 2-4 ohms--likely no lower or higher. The main secondary will be somewhat higher--and any LV secondaries will be a LOT lower likely.

[EdKozk2]

Originally Posted by zeno

I dont remember the name but its a special transformer
that uses an oil fill cap across one of the windings for
regulation. All Zenith colors used it from E-line through K
line. IIRC without the cap the transformer will pulsate.
I can dig tomorrow for the manual & give you the color codes.

73 Zeno

Thanks Zeno,
I thought someone would know about this transformer. The oil filled cap
you mentioned, are they still around ?
Ed

[Findm-Keepm]

Originally Posted by EdKozk2

Thanks Zeno,
I thought someone would know about this transformer. The oil filled cap
you mentioned, are they still around ?
Ed

Yep. The caps are similar to motor start capacitors. Zenith used them with Ferro-resonant transformers - a great way to economically get some regulation of output voltages. It is fairly old technology, but works great when the caps are healthy. I recall replacing maybe two or three of the caps in 20+ years of servicing Zenith Duramodule sets. The caps are 3.75 or 4 microfarads, at 240 volts, IIRC, and were standard size. I was in Lebanon, TN once, and had to fix my uncles Zenith - a trip to a local hardware store was all I needed to buy the cap, as they had an air conditioner motor start (or run, don't remember now) capacitor of the same value. Be careful - AC bites!

Cheers,