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Author Topic: Transformer ID  (Read 3492 times)
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Detroit47
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« on: May 07, 2018, 08:43:41 PM »

These two transformers are from a swap. The guy said they came out of an Alpha. No model number given. I checked them out with 120 vac in. I got these voltages out

RED 1674 VAC
OR VIO OR 42 Vct
Blu 14 vac
Yel 7.0
Any idea what they are out of. I am trying to figure what I can pull out of them.
John N8QPC


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Patrick J. / KD5OEI
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« Reply #1 on: May 08, 2018, 02:37:02 AM »

Here is my list of Alpha transformer AC voltages (AC unless DC is stated)
My guess would be model 86 or 89, Can you recheck the HVAC winding? -the manuals show more but who knows..
Both use two 3CX800s with 13.5V filaments.
The manuals are on http://bama.edebris.com/manuals/alpha/ so you may look at the schematics and see what matches. Sometimes there are options or weights stated and pics of the transformer. A clue is that there is one 15 pin connector. These are a little weird because they have but one primary winding and most Alphas have two, and some a third interconnected buck/boost. Could it be a 240V winding? There are other models and the best I can do is guess.

77DX 77SX
2x 120, 1800/2800VAC, 5VAC, ?wt-rd, wt-gry. 8877 tube 5VAC

374
2x 120 /w tap, HVDC 2200/1400 (pri.tap), 25-40VDC, 2 or 3x 8874s fil 6.3VAC

374A
2x120, 5 or 25VAC unclear connected to one 120V winding, 1100/1750VAC, 40VCT, 2x8874 fil 6.3VAC

PA-76, 76P, 76C
2x120, 25VAC (buck?) connected to one 120V winding, 1100/1750VAC, 40VCT, 2 or 3x 8874 fil 6.3VAC, option R for hi/lo HV

76A, 76PA, 76CA
2x120, 25VAC (buck?) connected to one 120V winding, 1100/1750VAC, 40VCT, 2 or 3x 8874 fil 6.3VAC, option for hi/lo HV

78
2x120, (110-130VAC/220-250VAC) 25VAC (buck?) connected to one 120V winding, 1100/1750VAC, 40VCT, 2 or 3x 8874 fil 6.3VAC, option for hi/lo HV

86
2x 110V, 25V, 1250/1885VAC, 50VCT, 7VCT, 13.5V(FIL), 2x 3CX800

89
200/220/240VAC, 1350/1900VAC, 7V, 51VCT, 13.6V(FIL), 2x 3CX800A7

91B
100/120V/200/220/240V,  2050V, 14V, 105V, 310V, 28VCT, 2x 4CX800/GU74B (12.6V fil)

PA-77
120/240V, 5V, 44VCT, HV 2400/3700VDC, one 8877 (6.3V fil)
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Detroit47
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« Reply #2 on: May 08, 2018, 12:48:02 PM »

Patrick
I tried 220 on the primary they didn't like that. I figure by wight maybe .6 kva not a lot of iron and the primary leads are pretty wimpy. I looked at all the different Alpha schematic and my old Peter Dahl catalog. The voltages look right for a 8874 box. The primary is what threw me. I wonder if they made any medical oscillators. It could be the guy I bought them from didn't know where they came from, and was blowing smoke.

John N8QPC
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KD6VXI
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« Reply #3 on: May 08, 2018, 01:23:37 PM »

ETO did mri and plasma generators.

--Shane
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W1ITT
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« Reply #4 on: May 08, 2018, 02:06:56 PM »

As Shane points out, ETO did  indeed make linear amplifiers for MRI.  I worked on a couple in GE MRI systems, running 3CX400A7s as I recall.   What struck me as odd was that they used 120 volt power input.   I run my ham station amps on 240, thinking that 120 vac is only for kids, lids and space cadets.   So probably stuffing 220 in would be "inappropriate".
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KB2WIG
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« Reply #5 on: May 08, 2018, 03:55:24 PM »



The 120 V winding is for short talkers.


KLC
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W1ITT
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« Reply #6 on: May 08, 2018, 04:49:11 PM »

http://hamgallery.com/Tribute/W2OY/w2oy2.wav

There may be a few onboard who don't know about W2OY, a 75m fixture from the 60s.  The otherwise obscure references in the above posts are to his distinctive style.
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