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Mystery Reactor




 
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N1BCG
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« on: March 31, 2018, 09:24:17 AM »

So frustrating...

I've been trying to identify this filter reactor that was installed in a homebrew modulator 50 years ago but have not been successful. The label on the top says:

E 10270 668 0280 C
Electro Engineering Works
San Leandro, California

From what I've found, "E10270" seems to be the most likely model number.

Thoughts?


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Tom WA3KLR
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« Reply #1 on: March 31, 2018, 10:24:43 AM »

Hi Clark,

I see another number which follows the old military/Federal Stock Number 4-3-4 xxxx-xxx-xxxx part number system. Looks like 6950-879-9508.  Search on the correct numbers. (By the way, the government added two more digits for country code in the middle there somewhere as I recall, in the early 1970's.)

Judging the size from the pilot lamp sockets next to it. It looks like a receiver/low power tx level of inductor.

Well. You have an ohmmeter and inductance meter I assume.  The square-wave drive-digital auto-ranging ohmmeters go wacko on an inductor sometimes. This is a niche where the old VOMs come in handy for inductor dc resistance.

For exploring some inductors one time, I put together a variac, transformer, bridge, inductor under test,  known capacitor, load resistor(s) in an choke input LC circuit.  I measured the peak-to-peak ripple voltage on a scope and ran simulations with LTSpice with the known values and adjusted the inductor value and ripple results until it matched the measured breadboarded value.  I ran different load currents and was able to make a plot of the inductance over a wide range of currents. (This gives you actual inductance under load!)
 
From experience with other chokes/data you have on hand/used, lead wire size, resistance,  along with the dive in the S-curve of inductance vs. dc load current, you should be able to come up with a ball-park current rating.
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73 de Tom WA3KLR  AMI # 77   Amplitude Modulation - a force Now and for the Future!
W1RKW
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« Reply #2 on: March 31, 2018, 11:03:49 AM »

country code would be 00 or 01 for the US and it would follow the first 4 digit number code with a hyphen. 

example: 1234-01-567-8910

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Bob
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His fear was when I turned it on for the first time life on earth would come to a stand still.
N1BCG
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« Reply #3 on: March 31, 2018, 03:49:36 PM »

The other number string looks like:

N5950-679-9508


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Tom WA3KLR
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« Reply #4 on: March 31, 2018, 04:06:58 PM »

A search on the correct FSN (now NSN with country code) yielded:

http://www.lintechcomponents.com/product/006799508/E10270/80008

Lintech     8 - 30 Henries, 100 Ohms, plus dimensions.

Does yours measure around 100 Ohms?  May be a generic family spec though, as current rating seems odd to me.
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73 de Tom WA3KLR  AMI # 77   Amplitude Modulation - a force Now and for the Future!
w1vtp
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« Reply #5 on: April 01, 2018, 11:29:17 AM »

A search on the correct FSN (now NSN with country code) yielded:

http://www.lintechcomponents.com/product/006799508/E10270/80008

Lintech     8 - 30 Henries, 100 Ohms, plus dimensions.

Does yours measure around 100 Ohms?  May be a generic family spec though, as current rating seems odd to me.

If those specs are correct, it sounds more like a power supply swinging choke not a modulation reactor.  Here's what I'm used to seeing in a mod reactor (see attachment). BTW it weighs about 80 lbs

Al


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N1BCG
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« Reply #6 on: April 01, 2018, 05:34:27 PM »

It certainly could be a swinging choke, particularly given its location in the power supply although the “pi” filter design ruins the choke input benefits.

And if that’s not enough, my mystery inductor hell continues with the power transformer, same modulator, with similarly scant details...


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KA2DZT
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« Reply #7 on: April 01, 2018, 06:02:33 PM »

The 138 number is a maker and date code. 138 made by Chicago, rest is the date code.  The 97 number looks familiar, probably made for RCA.  RCA had a lot of xfmr part numbers that started with 97xxxx
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N1BCG
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« Reply #8 on: April 01, 2018, 06:17:35 PM »

Interesting... I should also mention that the power transformer was ‘liberated’ from a massive color television :-)
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KA2DZT
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« Reply #9 on: April 01, 2018, 06:38:47 PM »

Interesting... I should also mention that the power transformer was ‘liberated’ from a massive color television :-)

Yes and most likely a RCA color TV.  The date code indicates (426) made in the 42nd week of 1956.  In 1956 all color TVs were made by RCA.  I remember those massive first generation color TVs.  All the second generation color TVs were made with RCA color TV chassis.  Picture tubes were all RCAs until Zenith finally developed there own color tube (early 60s).  Motorola also developed there own color tube but they were dogs.  Early on it didn't matter what brand color TV you bought the chassis were all made by RCA.

In the late 1960s I worked for Westinghouse Electric (engineering dept.), by then they had developed their own color TV chassis but they had thousands of RCA color TV chassis stacked up in the warehouse.  Probably never were used and got scraped.

I'll look up the info on that xfmr later and get back.

Fred
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Tom WA3KLR
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« Reply #10 on: April 01, 2018, 09:14:56 PM »

We don't know if the filter reactor is in fact a bonafide swinging choke or not.  
1. All iron core inductors will drop inductance as current increases.
2. If a genuine swinging choke is employed in a hobby power supply with capacitor input this is not a crime.
3. A swinging choke "throws way" its inductance faster/sooner than a smoothing choke as the current increases due to the air gap. The same inductor with less or no air gap starts out at the same inductance with little current and then the inductance drops less.
4. Swinging choke input supplies are not a high bandwidth regulated supply (120 Hz pulses for single-phase full-wave).
5. The swinging choke’s characteristic curve must be known and match the application’s current range for proper attainable regulation.
6.  This was all implemented in the days of high-vacuum rectifiers – high voltage drop/resistance compared to today’s silicon rectifiers with almost zero voltage drop.  Back then 8 - 10 uF was a typical largest capacitor value employed.  The best regulation today in a simple rectified supply is with silicon diodes and high capacitance (100's to 10,000's of uF easy) with an input choke of just enough inductance to keep the peak repetitive diode currents within the rating of the diode, about 1/4 of the critical inductance (always capacitor-input).  Today you can even get FILM capacitors in the 800 Vdc thousands of uF range (size - like the big old "computer-grade electrolytics"), called dc link capacitors.
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73 de Tom WA3KLR  AMI # 77   Amplitude Modulation - a force Now and for the Future!
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Patrick J. / KD5OEI
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« Reply #11 on: April 01, 2018, 10:02:46 PM »

Is it not the reverse, that with two identical chokes, the one with the air gap resists saturation longer and is not the swinging but the 'fixed' inductance smoothing choke?
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KA2DZT
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« Reply #12 on: April 01, 2018, 10:14:43 PM »

I think swinging chokes have little to no air gap.  I think it's the only difference between swinging and smoothing chokes.  Maybe I have it backwards.

The theory with swinging chokes is with little current they have a high inductance.  Higher current loads, like from class B modulators, drops the input inductance bringing the filter closer to a cap input filter.  This causes the voltage to increase.  Swinging chokes are suppose to improve regulation.  They probably did back in the day when you were lucky to have 2-4ufd filter caps.  Today with high filter capacitance being used swinging chokes outlived they usefulness but it doesn't mean you shouldn't use one.

Fred

When Thordarson produced their last series of filters chokes (21 series) they only made one type in each current range.  The 21 series chokes were a cross between swinging and smoothing.  Thordarson stated that swinging chokes were really no longer needed so they only produced these hybrid type chokes.
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KA2DZT
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« Reply #13 on: April 02, 2018, 02:26:01 AM »

I checked out that RCA TV xfmr.  971718-1-2 cross reference to Thordarson 26R58 and Stancor P-8167.

The specs for the Stancor P-8167  Primary 117v 60Hz  Secondary  560vct 400ma, 5v 6a, 6.3v 4.5a, 6.3v 8.5a.   I would have to hunt down the specs for the Thordarson 26R58 which I have but can't remember which Thordarson book it's in.  The specs for the Thordarson would be very much the same as the Stancor.

Fred

I should also add that the Thordarson and Stancor xfmrs are direct replacements for the RCA xfmr.  So your xfmr would have the same specs.
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N1BCG
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« Reply #14 on: April 02, 2018, 03:03:42 PM »

A search on the correct FSN (now NSN with country code) yielded:

http://www.lintechcomponents.com/product/006799508/E10270/80008


Hey Tom.... THANKS!!!  That seems to be it although I hadn't expected it to be a swinging choke given the input cap, but hey, it seems as though the builder used whatever components were available.
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N1BCG
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« Reply #15 on: April 02, 2018, 04:10:02 PM »

I checked out that RCA TV xfmr.  971718-1-2 cross reference to Thordarson 26R58 and Stancor P-8167.

The specs for the Stancor P-8167  Primary 117v 60Hz  Secondary  560vct 400ma, 5v 6a, 6.3v 4.5a, 6.3v 8.5a.   I would have to hunt down the specs for the Thordarson 26R58 which I have but can't remember which Thordarson book it's in.  The specs for the Thordarson would be very much the same as the Stancor.

Fred - You guys are THE BEST!!!   What an awesome group!

I've had this transmitter since 1984 and only now is there some meaningful documentation!
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N1BCG
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« Reply #16 on: April 02, 2018, 05:49:35 PM »

I thought you guys might be curious about the transmitter. A 4x4 with 8 6146s in AF and RF...


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Tom WA3KLR
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« Reply #17 on: April 02, 2018, 08:05:48 PM »

Here's an old thread on swinging chokes:

http://amfone.net/Amforum/index.php?topic=18829.0
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73 de Tom WA3KLR  AMI # 77   Amplitude Modulation - a force Now and for the Future!
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