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Author Topic: stancor 14208 choke value?  (Read 3139 times)
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NR5P
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« on: June 20, 2013, 09:27:47 PM »

I was running through my junk shed today looking for parts for a modulator I'd like to eventually build.  I found 4 stancor 14208 transformers.  They appear to be choke filters?  Does anyone know the value?  I've had a hard time finding anything on them. 
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KA2DZT
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« Reply #1 on: June 21, 2013, 12:19:04 AM »

Five digit part numbers are specials.  You won't find any info on them.  You need to know what piece of equipment they were made for.  Then check the manual to find what they are.

You can also take a guess as to what they are.  First measure the DC resistance and look at the size.  Do they have HV type terminals?

Post some pictures, maybe someone might know more about them.

Fred
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NR5P
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« Reply #2 on: June 21, 2013, 12:54:08 AM »

Oh ok, thanks for the info.  I have no clue what these came from.  I got these with a bunch of other stuff at a ham fest a long time ago.  I measure 660 ohms across the windings.  weighs 2.25 pounds.  I haven't measured the windings on the others, but they look just like this one. 


* choke.jpg (1823.07 KB, 1936x2592 - viewed 445 times.)
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W7TFO
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« Reply #3 on: June 21, 2013, 01:33:18 AM »

Looks pretty small.  High Ohms, so low current, maybe high Henry.

73DG
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AB2EZ
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"Season's Greetings" looks okay to me...


« Reply #4 on: June 21, 2013, 12:12:39 PM »

Assuming these are chokes (not transformers with multiple windings): put the choke in series with a 10,000 ohm, 2 watt resistor. Put a 120V (rms) 60Hz sine wave across the pair in series. Measure the rms voltage across the choke, and the rms voltage across the 10,000 ohm resistor. [If you don't have a 2W resistor, you can use a filament transformer to produce 12.6VAC across the series combination of the choke and the 10,000 ohm resistor. In that case, even a 1/4 watt resistor will suffice.]

To a good approximation* (i.e., ignoring the series resistance of the choke)... the inductance of the choke is:

L = [(1/377) x 10,000 x Vchoke / Vresistor] Henries

If these are transformers (multiple windings, and or multiple taps from a winding), then making the above measurement will produce what is known as the "magnetizing inductance" of the transformer, referenced to the winding you are using.

*If you want a more accurate result, post the measured voltage across the choke and the measured voltage across the 10,000 ohm resistor (and recheck/post the value of the series resistance of the choke). I'll reply with the more accurate value for the inductance of the choke.

Stu
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KA2DZT
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« Reply #5 on: June 22, 2013, 01:19:58 AM »

Looked at the picture.  They're too small to be a xmtr/mod choke.  They probably measure 200-300 ohms.

Kenyon made their xfmrs and chokes with the same case style.  Very unlikely that Kenyon made the chokes for Stancor.

Fred
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