power choke with 3 leads

What are the resistances?

Common Mode chokes will have three (or more) wires - they are designed to filter rF and reduce EMI (for the most part, not always).

Peter Wieck Melrose Park, PA

Yes, I am aware of the common chokes for RF. However this is a large iron core choke similar in size and make up of a 2 wire choke used in the DC supply of a radio or old tube TV set.

There seems to be one winding with a tap on it. From one end to the other is about 280 ohms. From one end to another wire is 272 ohms and the other is 8 ohms.

Again this is an iron core choke ? that is large enough to be used as a normal 2 wire power supply choke in a tube type TV set of the 1950's .

This sounds more like an transformer, with one contact common between primary and secundary, than a choke.

Does it have an airgap in the core?

There is no airgap that I can see. It could be an autotransformer. While I am familiar with simple tube circuits, the old TV sets are before my time so to speak. I would still like to see how it would be used in an application.

Ralph Mowery wrote: =================

..... Phil

I am not familiar with that kind of speaker transformer. Are you saying it is used in a method coming off the audio tube plate in a maner similar to an autotransformer is used in power line circuits ?

It may make sense as there is a low resistance in series with a high resistance winding.

Ralph Mowery wrote: =================

There would still need to be an air gap cos of unbalanced DC current in the primary. Just means all the Es and Is are lined up and not interleaved.

Quick and very easy transformer to make.

..... Phil

Tapped series chokes were once used for voltage selection under very dedicated load conditions ~ fan speed control or heater settings.

Perhaps it's a tube heater (12 - 6V) range.

RL

Autotransformer. If it were a single center tap winding, applying

It is really old, more than 40 years old that I know of and much older than that as it came out of a black and white TV as best as I can remember. The total resistance is about 280 ohms with a tap of about 8 ohms from one end.

Guess it could be for a couple of filiments of some of the old tubes it was mentioned that it could be the plate transformer of the audio stage to speaker . As the set it came out of was probably as old or older than I am I have not seen a tube circuit that used a transformer that way . I am just not up on the very old tube circuits.

If it was a standard transformer that put out 6.3 volts it would be good for about 3 to 5 amps judging by its size. All the E cores are facing one direction and the I segments are all at one end instead of alternating like most transformers.

That shows it is designed to handle DC or a very asymmetrical waveform. My guess would be a frame output autotransformer for driving the field coils around the tube neck.

legg wrote more crap: ===================

latter day info.

latter day phil being his useful, helpful self.

RL

Liz Tuddenham wrote: =================

Well spotted.

.... Phil