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Can someone identify this mod transformer?




 
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Author Topic: Can someone identify this mod transformer?  (Read 15111 times)
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Opcom
Patrick J. / KD5OEI
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« Reply #25 on: June 05, 2009, 07:56:21 PM »

aside from it being said it was used for this or that, remember the old beachmaster PA system? It couldn't be from one of those could it?
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ke7trp
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« Reply #26 on: June 05, 2009, 08:47:45 PM »

Its not repainted and that sticker is factory.  We had two of them brand new in the boxes.  One is in the 610 as a modulator. The other is on my desk.  This ran the Y tubes. Probably with a reactor.

The boxes match the part number of the transformer.

CLark
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W2PFY
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« Reply #27 on: June 05, 2009, 09:04:46 PM »

please,may i have one?
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ke7trp
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« Reply #28 on: June 05, 2009, 09:34:44 PM »

There is an issue of reading what people are posting....   I never SAID IT WAS FOR A BC610!!!   I said it was used in one for a time period.  The stock mod iron failed and this was used as a temp replacement.  If I misled you guys I am sorry.. I dont know how to make myself anymore clear..

Also.. Please dont say it wont work. in a BC610  It does work. Is it optimal? No.  Does it work as a mod transformer? Yes. 

I have decided not to use it for my Radio. I was going to toss it in and fire up the rig so I could repair other areas of the transmitter while I searched for the money for a proper replacement. But according to the thread and the emails I got its going to BLOW MY ENTIRE RADIO UP.. LOL

Thanks for the help as always guys!! I love hearing about all the interesting uses for this thing!! I am sure someone can use it!!

Clark
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KE6DF
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« Reply #29 on: June 05, 2009, 10:28:25 PM »

BTW, there is a BC-610 modulation transformer available on ebay right now:

http://cgi.ebay.com/NEW-MILITARY-BC-610-STANCOR-MODULATION-TRANSFORMER_W0QQitemZ120429473572QQcmdZViewItemQQptZVintage_Electronics_R2?hash=item1c0a27ef24&_trksid=p3286.c0.m14&_trkparms=65%3A10%7C66%3A2%7C39%3A1%7C240%3A1318%7C301%3A1%7C293%3A1%7C294%3A50
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N3DRB The Derb
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« Reply #30 on: June 06, 2009, 06:11:18 AM »

now that would is supposed to work in a bc 610.
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ke7trp
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« Reply #31 on: June 06, 2009, 10:34:52 AM »

I dont have a BC610.   

I love that add..   Selling it as new.. Its clearly rusted and weathered..

C
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« Reply #32 on: June 06, 2009, 11:30:40 AM »

Good luck with it.
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ke7trp
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« Reply #33 on: June 22, 2009, 12:21:54 AM »

I am going to sell this transformer if anyone wants it.  Trying to find a transformer that will work for the 810s and 4-400s.

CLark
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ke7trp
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« Reply #34 on: August 20, 2009, 12:55:53 AM »

Does anyone see any reason this wont work if I hook the 70 volt output of a large PA amp to the 40 ohm taps and tun the Secondary to the 4-400s?   Still need a choke?

Clark
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KM1H
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« Reply #35 on: August 20, 2009, 09:18:51 AM »

There is no way that was ever designed to drive speakers. With those HV standoffts even the thought is ludicrous.

If it was really used with 4CX300Y's it would have to be after 1963 and aircraft were able to exceed 10000' by then Roll Eyes The height markings mean that it was not built for aircraft use, those are strictly ground ratings.

The Y is substantially different than the A version. 400W Pd, only 110 mc full ratings and of note, spec'ed for AM linear service.

My guess it was part of a cathode driven pulse modulator for industrial use. It would be interesting to see what the frequency response is.

Carl
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W2PFY
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« Reply #36 on: August 20, 2009, 10:17:18 AM »

Quote
Does anyone see any reason this wont work if I hook the 70 volt output of a large PA amp to the 40 ohm taps and tun the Secondary to the 4-400s?   Still need a choke?

I thought this thread died?? I spelled this out for you in a past thread, I don't see any reason it could not be used. If you can't get adequate modulation, you may have to use a choke. I wish I owned that transformer.
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ke7trp
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« Reply #37 on: August 20, 2009, 01:18:17 PM »

I got the Globe king done so now I want to move back to this project and I just need some help. I thank you for the info.. But thats my questions. Should I use a choke and cap?   

I dont know what it was for..All I can tell you guys is what I was told it was used for. 

C
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Gito
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« Reply #38 on: August 20, 2009, 07:49:16 PM »

Hi


Clark to used the modulation Trafo,you must know the load  impedance of the transmitter,
if We used a 2500 v B + for 4-400 and load it for 250 ma than we had 2500 v divided by .250 A = 10 kilo ohm,
sometimes we need a higher impedance ,so we used a 3000 v and load 4-400 for 200 ma we got 3000 v divided by  0.200= 15 k ohm,

so by loading having the right voltage and right loading current we can get the impedance we want ,of course sometimes we get less power out put than the optimal output.

So can we used this trafo to modulate the 4-400  with a P.A amplifier ?
first we must know ,or at least looking by the wight of it,how many watts it can delivered . Since two  4-400  with 2000V loaded to 500 ma has an input power of 1000 watt, and a impedance of  4 K ohm .

If the mod. Trafo has a 2000 watt rating we don't need a choke and a cap ,since the current flow in the transmitter side  is 500 ma , it can't saturate the Mod. trafo ,since the wattage that it used 1000 watt for the transmitter + 500 watt for the Modulator( to modulate a transmitter we must have 50% power of the transmitter input to 100% modulate it.)

But if the Mod trafo has only a 1000 watt rating  we must used a choke and a cap to stop the current that is flowing in the transmitter side of the Mod trafo,So it is not saturated.
 
When we have two 4-400 with 2000 V  loaded to 500 ma we have a 4 Kohm impedance

Looking at this "Mod trafo you have" it has  14 Kohm to 40 ohm ratio,so as when we used it for the 4-400 transmitter  with 4 K ohm than it looks like 11 Ohm  at the other end,
So using A PA with a 8 or 12 Ohm output we can modulate the 4-400 transmitter,since the turn ratio is right.

But maybe the frequency response may or may not  be as good as the trafo is designed fore.

higher  impedance for  a frequency response means more turns / winding  in the trafo,because  needs a higher  inductance (Henry) .

So an output trafo /mod trafo  is design to have enough turns /winding at the impedance of the mod.tube and have a compromise value /inductance for a frequency range, for example we need a frequency range from 500 Hz to 3000 Hz,
Then we choose  1000 hz  to find the inductance at that frequency at the impedance of the  Trans former (modulator tube side)

But of course its not simple as that,winding this trafo.

So when we used a mod Trafo with not the right impedance ,but with the right turns ratio it will work,maybe with a difference  audio frequency response,
more gain at lower audio ,with loss of higher frequency .or the opposite side more gain at the higher tones and loss of the lower frequency/bass tones.

If we get a 6 k ohm primary and a 6 k ohm secondary modulator trafo

Can we used it as 9 K ohm to 9 k ohm,I believed we could as the turn ratio is right.
or used it as 4 K ohm to 4 k ohm ,Yes we can.


Gito



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