webster: Type 4?; Power Pac A-C (AC) or Battery E

I have been working on this thing for a few days now. It has been very difficult as the color of the cables are faded away and you have to follow each connection by hand. It doesn’t help that they used some kind of glue to hold everything together and now that is crumbling.

I have tested the two main transformers, the primaries seem to be ok. I only applied 10v to them and measure the secondary. I used a little math to calculate the final output. So far this is what I have found out:

T1 (T1 and T2 are the two main transformers), primary winding has 4 taps on it, I calculated that they are: 5.5v, 43.5v, 78.7v and 92.1v. The taps are connected directly to back terminal screws. The secondary as 3 leads with 5.5v and a center tap (sorry I drew the attachment wrong)

T2 has a secondary with 3 leads and the go to the pins of the socket. If my calculations are correct then at 115v on the primary the outside leads on the secondary will be at 586v, the tap in the middle produces 293v to each side.

I have a few questions:

• Does anyone have seen the configuration described for T1? With all those taps from the primary going into the connecting panel.
• Normally in the rectifiers circuits that I have seen, it should be a connection between the two transformers. Or this make sense?
• With the voltages that I described for T2, would UX280 will be a candidate for this?

I’m still working on creating a schematic for this, takes time as I have to redraw the whole thing when it becomes too tangle.

Thanks

Daniel Kolbach

Attachments:

• Diagram (220 KB)

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0 5.5v, 43.5v, 78.7v and 92.1v.

or Add 5.5 to 38.5, 73.2 or  86.6

maybe though its for 110V & 220V etc?

that would make the small tap a 16V change, so 110V or 116V.

73.2 gives 209 (or 225 with other tap)

86.6 gives 247 (or 263 with other tap)

The filament would be centre tapped to reduce hum. So are you sure about the filament volts?

It's common to have a small tap at one end of primary for fine adjustment. But 5.5V seems too small.

The filament voltage is more critical than HT, hence lots of adjustment.

The HT rectifier needs to be able for total voltage across winding and about 15mA to 20mA. The centre tap is earthed. You need an indirect insulated heater or else the filament winding can ONLY feed the rectifier. Perhaps it was only an HT eliminator, then there isn't a problem.

Was there Mains supplies as low as 38 to 44V ever? If not then it's a transformer for 90V or 220 nominal with a 16V adjustment. Then the filament is either 16V or there is a mistake in the measurements.

 

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