Steve - K4HX
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« on: May 19, 2013, 12:51:08 PM » |
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Got a couple of questions from a fellow ham in a letter recently.
1. What is the impedance or turns ratio of the BC-610 mod transformer?
2. What are the maximum current ratings (both primary and secondary) of the BC-610 mod transformer?
3. Does anyone have the connection info for a Merit A-3120 driver transformer.
He's looking to use these in a homebrew rig using 2A3 drivers, 811A modulators and a 4-250 final.
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W8ACR
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« Reply #1 on: May 19, 2013, 02:21:09 PM » |
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Steve,
The mod transformer is 21000 ohm primary to 8000 ohm secondary, 250 watt rating. Merit 3120 is 500 ohm line to multiple secondary tap, step up, 15 watt rating. The 250TH is run at 250mA for phone operation.
Ron
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The life of the nation is secure only while the nation is honest, truthful and virtuous. Frederick Douglass
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KA2DZT
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« Reply #2 on: May 19, 2013, 02:32:11 PM » |
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1.62/1 turns ratio. Have to run the 811s at the same voltage as the final to just make 100%.
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Steve - K4HX
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« Reply #3 on: May 19, 2013, 02:58:35 PM » |
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TNX gentlemen. What is the plate voltage on the BC-610. I should know this since I've had a few BC-610 plate trannies over the years.
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KA2DZT
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« Reply #4 on: May 19, 2013, 03:04:32 PM » |
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I have a 610 plate xfmr. Two level plate voltage, primary is tapped, I think 2200DC - 2500DC. after filters. A lot of Stancor plate xfmrs were labeled with the DC output voltage (under load after filters) rather than the AC winding voltage.
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W8ACR
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« Reply #5 on: May 19, 2013, 03:38:47 PM » |
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According to the manual, The final amp plate voltage is 2500VDC on CW and 2000VDC on phone. (TM11-826, page 65)
Ron
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The life of the nation is secure only while the nation is honest, truthful and virtuous. Frederick Douglass
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W2PFY
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« Reply #6 on: May 19, 2013, 04:40:29 PM » |
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I actually measured the voltage on my BC610D under load at 250 ma plate current and 50 ma resting current on the modulators at 2125 VDC with a Fluke meter and a Fluke HV probe. The line voltage was 125 vac. The plate meter is in the anode circuit, not the cathode.
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Steve - K4HX
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« Reply #7 on: May 19, 2013, 08:07:04 PM » |
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Good stuff. Thanks.
If anyone has the connection info for the Merit tranny, let me know.
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W2VW
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« Reply #8 on: May 19, 2013, 08:09:19 PM » |
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Late BC-610 xfmr was rated @ 4800/5720 VCT IIRC .321A.
In reality a late BC-610 xfmr has enough poop to make the old legal limit out the pipe on AM without breaking a sweat.
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Steve - K4HX
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« Reply #9 on: May 19, 2013, 08:17:17 PM » |
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When you say "late", do you mean the potted tranny instead of the older open frame units?
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W2VW
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« Reply #10 on: May 19, 2013, 08:25:49 PM » |
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Late as in oil filled cube with two primary taps.
BC-610 F and up IIRC.
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Steve - K4HX
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« Reply #11 on: May 19, 2013, 09:08:48 PM » |
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Got it. TNX.
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ashart
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« Reply #12 on: May 21, 2013, 10:09:49 AM » |
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Here is Merit A-3120 data.
The data given for turns ratios (pri to 1/2 sec) should allow reasonably easy determination of pinouts, remembering that (Z1/Z2) = (N1/N2)^2.
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Steve - K4HX
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« Reply #13 on: May 21, 2013, 07:33:16 PM » |
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Thanks. I have that catalog. I'm looking for the actual terminal connection info.
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