• power choke with 3 leads

    From Ralph Mowery@21:1/5 to All on Mon Aug 2 16:13:21 2021
    In article <971fb451-8912-4640-bad7-d50c0c2e2a5an@googlegroups.com>, peterwieck33@gmail.com says...

    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.

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  • From Ralph Mowery@21:1/5 to All on Mon Aug 2 16:25:26 2021
    In article <MPG.3b7227b6e9cda2ba113@news.plus.net>,
    gravity@mjcoon.plus.com says...

    A friend found a choke in his junk box and asked about it. I found one similar to it in mine. They are iron core chokes similar to the old
    tube TV power supply section would have in it. They are probably over 50 years old and most likely came from an old TV set.

    The question is why do they have 3 wires instead of 2 wires that the
    other chokes I have seen have ?

    I know they are not the output transformer of a push pull audio stage
    that may have had the speaker wires cut off, but that is what they resemble.

    What are the resistances?



    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 .

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  • From Rob@21:1/5 to Ralph Mowery on Mon Aug 2 23:19:31 2021
    Ralph Mowery <rmowery42@charter.net> wrote:
    In article <MPG.3b7227b6e9cda2ba113@news.plus.net>,
    gravity@mjcoon.plus.com says...

    A friend found a choke in his junk box and asked about it. I found one
    similar to it in mine. They are iron core chokes similar to the old
    tube TV power supply section would have in it. They are probably over 50 >> > years old and most likely came from an old TV set.

    The question is why do they have 3 wires instead of 2 wires that the
    other chokes I have seen have ?

    I know they are not the output transformer of a push pull audio stage
    that may have had the speaker wires cut off, but that is what they
    resemble.

    What are the resistances?



    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?

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  • From Ralph Mowery@21:1/5 to All on Mon Aug 2 17:42:36 2021
    In article <slrnsggob2.qlh.nomail@xs9.xs4all.nl>, nomail@example.com
    says...

    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.

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  • From Phil Allison@21:1/5 to Ralph Mowery on Mon Aug 2 15:53:24 2021
    Ralph Mowery wrote:
    =================

    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.

    ** Could be a speaker transformer.
    The TV set would have a live chassis.



    ..... Phil

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  • From Ralph Mowery@21:1/5 to All on Mon Aug 2 18:59:42 2021
    In article <9ebae237-0c57-42bd-af5a-1dd85fec6bf3n@googlegroups.com>, pallison49@gmail.com says...

    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.

    ** Could be a speaker transformer.
    The TV set would have a live chassis.


    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.

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  • From Phil Allison@21:1/5 to Ralph Mowery on Mon Aug 2 17:10:09 2021
    Ralph Mowery wrote:
    =================


    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.

    ** Could be a speaker transformer.
    The TV set would have a live chassis.

    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 ?

    ** Yep.

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

    ** I imagined there is one continuous winding with a tap at 8/280.
    That is a voltage ratio of 35:1 or an impedance ratio of 1225:1

    About what you expect for a single ended, pentode output stage.

    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

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  • From legg@21:1/5 to rmowery42@charter.net on Wed Aug 4 08:16:06 2021
    On Mon, 2 Aug 2021 10:57:20 -0400, Ralph Mowery
    <rmowery42@charter.net> wrote:



    A friend found a choke in his junk box and asked about it. I found one >similar to it in mine. They are iron core chokes similar to the old
    tube TV power supply section would have in it. They are probably over 50 >years old and most likely came from an old TV set.

    The question is why do they have 3 wires instead of 2 wires that the
    other chokes I have seen have ?

    I know they are not the output transformer of a push pull audio stage
    that may have had the speaker wires cut off, but that is what they
    resemble.

    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

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  • From Jeff Liebermann@21:1/5 to rmowery42@charter.net on Wed Aug 4 11:03:42 2021
    On Mon, 2 Aug 2021 10:57:20 -0400, Ralph Mowery
    <rmowery42@charter.net> wrote:

    A friend found a choke in his junk box and asked about it. I found one >similar to it in mine. They are iron core chokes similar to the old
    tube TV power supply section would have in it. They are probably over 50 >years old and most likely came from an old TV set.

    The question is why do they have 3 wires instead of 2 wires that the
    other chokes I have seen have ?

    I know they are not the output transformer of a push pull audio stage
    that may have had the speaker wires cut off, but that is what they
    resemble.

    Autotransformer. If it were a single center tap winding, applying
    120VAC between the tap and one common end, would produce 240VAC
    between the common end and the other end. I suspect it's really old
    as such an arrangement might be considered an electrocution hazard. <https://en.wikipedia.org/wiki/Autotransformer> <https://www.google.com/search?q=autotransformer&tbm=isch>

    --
    Jeff Liebermann jeffl@cruzio.com
    PO Box 272 http://www.LearnByDestroying.com
    Ben Lomond CA 95005-0272
    Skype: JeffLiebermann AE6KS 831-336-2558

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  • From Ralph Mowery@21:1/5 to All on Wed Aug 4 14:28:18 2021
    In article <u9llggp8n498qt8pk1iu8u195tvrqdtlq3@4ax.com>,
    jeffl@cruzio.com says...

    Autotransformer. If it were a single center tap winding, applying
    120VAC between the tap and one common end, would produce 240VAC
    between the common end and the other end. I suspect it's really old
    as such an arrangement might be considered an electrocution hazard. <https://en.wikipedia.org/wiki/Autotransformer> <https://www.google.com/search?q=autotransformer&tbm=isch>




    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.

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  • From Liz Tuddenham@21:1/5 to Ralph Mowery on Wed Aug 4 21:18:02 2021
    Ralph Mowery <rmowery42@charter.net> wrote:

    ...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.


    --
    ~ Liz Tuddenham ~
    (Remove the ".invalid"s and add ".co.uk" to reply)
    www.poppyrecords.co.uk

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  • From Phil Allison@21:1/5 to legg on Wed Aug 4 15:29:28 2021
    legg wrote more crap:
    ===================

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


    ** Not with a source impedance of around 16 ohms.

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  • From legg@21:1/5 to pallison49@gmail.com on Wed Aug 4 20:55:15 2021
    On Wed, 4 Aug 2021 15:29:28 -0700 (PDT), Phil Allison
    <pallison49@gmail.com> wrote:

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

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


    ** Not with a source impedance of around 16 ohms.

    latter day info.

    latter day phil being his useful, helpful self.

    RL

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  • From Phil Allison@21:1/5 to Liz Tuddenham on Wed Aug 4 18:27:26 2021
    Liz Tuddenham wrote:
    =================

    ...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.


    ** Now the OP finally reveals how large the tranny is - yes.

    Well spotted.


    .... Phil

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