RCA 86-A Compressor XFMR
- Thread starter CJ
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From the schem:
2070:2070 DCR
One I had actually measured 2200 : 2043 DCR, another 2022 : 2178 DCR, later one:
1-3) 2022R 104H7
4-5) 1102R 27H3
5-6) 1084R 26H8
4-6) 2178R 105H
Henries from an Extech handheld meter at 120Hz, parallel (High-Z) measurement
2070:2070 DCR
One I had actually measured 2200 : 2043 DCR, another 2022 : 2178 DCR, later one:
1-3) 2022R 104H7
4-5) 1102R 27H3
5-6) 1084R 26H8
4-6) 2178R 105H
Henries from an Extech handheld meter at 120Hz, parallel (High-Z) measurement
Last edited:
Could be some shorted turns thus lower DCR,
and DCR changes when the coil is on the core for some strange reason which I have yet to figure out but have some theories like inductance messing with the volt meter , usually more pronounced on a nickel core,
From the DCR on the print I suspect a 1:1 turns ratio , twin coils like the BA6a innerstage and equal wire size.
and DCR changes when the coil is on the core for some strange reason which I have yet to figure out but have some theories like inductance messing with the volt meter , usually more pronounced on a nickel core,
From the DCR on the print I suspect a 1:1 turns ratio , twin coils like the BA6a innerstage and equal wire size.
Wonder why the use a xfmr for the side chain, BA6a just uses caps
Done with the take-part,
Pretty weird XFMR,
E-E core, not in the catalog,
Butt stacked. No paper in the gap.
0.7" tongue, 1 inch stack. Probably steel,
6800 turns center tapped primary,
The primary wind has two pies of 3400 turns each. #38 AWG,
Wound on an over sized mandrel, 42 layers! Obscene to unwind. And wind.
The coil is sawn in two. One of the pies is flipped around as to simulate a reverse wind. Both pies are then slipped over the first secondary section.
Then the last secondary section is wound.
The split secondary does not have even turns. The inner section is 1700 turns #38 and the outer section is 3400 turns of #38.
So 6800 to 5100 or 1:1.33 ratio
Or 0.75 to 1 if you prefer.
Pictures at 11.
Pretty weird XFMR,
E-E core, not in the catalog,
Butt stacked. No paper in the gap.
0.7" tongue, 1 inch stack. Probably steel,
6800 turns center tapped primary,
The primary wind has two pies of 3400 turns each. #38 AWG,
Wound on an over sized mandrel, 42 layers! Obscene to unwind. And wind.
The coil is sawn in two. One of the pies is flipped around as to simulate a reverse wind. Both pies are then slipped over the first secondary section.
Then the last secondary section is wound.
The split secondary does not have even turns. The inner section is 1700 turns #38 and the outer section is 3400 turns of #38.
So 6800 to 5100 or 1:1.33 ratio
Or 0.75 to 1 if you prefer.
Pictures at 11.
What is the effect of stray capacitance on total coil capacitance?
Wrong.
The correct answer is
It depends on the coil geometry.
The correct answer is
It depends on the coil geometry.
there is an important detail in this out of focus pic,
a clue that helps verify that a coil was wound and then slid off the mandrel and placed over the inner secondary,
notice the arc in the winding below the blue arrow.
this arc is there because they did not want the core tube to collapse once the coil was taken off the mandrel.
so the mandrel was shaped to have an arc in it.
42 layers can build up quite a force so they used Roman archetecture (sp) to add strength.
i was wondering why the coil had quite an oval shape to it.
a clue that helps verify that a coil was wound and then slid off the mandrel and placed over the inner secondary,
notice the arc in the winding below the blue arrow.
this arc is there because they did not want the core tube to collapse once the coil was taken off the mandrel.
so the mandrel was shaped to have an arc in it.
42 layers can build up quite a force so they used Roman archetecture (sp) to add strength.
i was wondering why the coil had quite an oval shape to it.
Attachments
balanced primary, you can see the saw line, sector on the left is reverse wound.
or the sector on the right, depending on how you want to look at it, because the secondary also has one of the sections reverse wound.
no wait, the primary did not have a reverse wind, one of the sectors was truned 180 degrees and slipped over the secondary section after the band saw, which now gets hooked up as a reverse wind, DCR equal, capacitance equal, maybe even a bit of hum cancel from external fields,
or the sector on the right, depending on how you want to look at it, because the secondary also has one of the sections reverse wound.
no wait, the primary did not have a reverse wind, one of the sectors was truned 180 degrees and slipped over the secondary section after the band saw, which now gets hooked up as a reverse wind, DCR equal, capacitance equal, maybe even a bit of hum cancel from external fields,
Attachments
and the last layer of the inner secondary, 1800 turns , 9 layers,
there were a few busted wires on the outer secondary, this is the side of the coil that
has DC from the tube running through it, probably 24/7 if this guy was sitting on a radio transmitter out in Topeka Kansas somewhere,
there were a few busted wires on the outer secondary, this is the side of the coil that
has DC from the tube running through it, probably 24/7 if this guy was sitting on a radio transmitter out in Topeka Kansas somewhere,
Attachments
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