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 Post subject: 120v to 4800 v transformer
PostPosted: Sun Jan 08, 2017 4:44 pm 

Joined: Fri May 10, 2013 12:55 pm
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What do I do with a used 120 V to 4800 V transformer from 1994???

I found an old transformer I picked up in 1994 at a junk shop.
It was already used 22 years ago. It was taken out of junked equipment.
I don't know what it was taken out of.

Its specs:
* 120V primary, 10mA
* other end is 4800 volts
* transformer says: coiltron, 20956 (model?) and 8946 (was stamped crookedly, a date stamp?)
* measures 3 inch across

Where do you think it came from? What projects would this be good for?


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 Post subject: Re: 120v to 4800 v transformer
PostPosted: Sun Jan 08, 2017 6:01 pm 
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I'm pretty sure that's a transformer out of a Microwave.
It steps up the voltage for the Magnetron.

As for use......
Maybe make it part of a power supply for a Tesla Coil, or make a Jacobs ladder.


Signed: Janitor Tzap


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 Post subject: Re: 120v to 4800 v transformer
PostPosted: Sun Jan 08, 2017 6:18 pm 
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Location: Maryland
Well, first be careful, that transformer could easily be lethal.

Is the secondary of the transformer is center tapped, that will be 2400V to ground, and yes, the transformer metal case should be grounded. The 4800 would be across the full winding.

Are the terminals wire leads, as if the transformer were enclosed in a piece of equipment, or are they exposed for wire connections?
If they are exposed it may be a transformer for a neon sign. The length and diameter of the neon tube determines the voltage, and current needed so this chart may help!
http://www.sfeg.com/blog/how-to-find-the-correct-neon-transformer-using-the-luminous-tube-footage-chart

At 4.8Kv that kind of leaves out X-ray and oil burner ignition since these transformers are much higher voltage and current. Since you didn't mention any other windings, that leaves out a microwave oven since they also need a high current filament winding.

It may make a a miniature Jacob's Ladder (Google it) but at that voltage reliable starting will depend a great deal on the electrode spacing.

Aside from this, post a picture and send an email to Coiltron with the picture and the specs.
It seems that http://www.coiltron.com/transformers/ may be the same company.

Hope this helps!



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 Post subject: Re: 120v to 4800 v transformer
PostPosted: Sun Jan 08, 2017 9:10 pm 

Joined: Fri May 10, 2013 12:55 pm
Posts: 9
Here's the transformer.
It has four wires. Two and two.


Attachments:
transformer.jpg
transformer.jpg [ 695.61 KiB | Viewed 810 times ]
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 Post subject: Re: 120v to 4800 v transformer
PostPosted: Mon Jan 09, 2017 7:26 am 
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Location: Maryland
Well, that's about as generic as it gets.
Thumbs down now on microwave, oil burner and neon.
I'll vote for a bug zapper! 5kv is common for zappers.

Coiltron impressed me as being more of a custom oem supplier than an off the shelf company, so maybe that's the purchaser's part number.

Go zap them bugs!



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 Post subject: Re: 120v to 4800 v transformer
PostPosted: Mon Jan 09, 2017 12:00 pm 
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most likely it is not a MOT, as 10Ma. is nothing..
most likely it is a transformer used in a bug zapper,,
i have come across many of them at that voltage and Ma. range..
i have some 5ft tall commercial bug zappers made by Flintrol, had 4ft black lights in them.
usually either the ballast or zapping transformer was bad.. i beefed em up with 5kv @ 30ma ( neon transformers )
watchem bugs splode.. bug zappers had a catch try under them, and after a good night of zapping, the tray would be 1/2 full..

transformer could also have possibly been used in a tube amp or transmitter ??

looking at the posted pic.. i seen something like that before, but it was in a super old B&W tv set, that had a neon tube around the CRT.
not sure but i think it was 1950's sylvania halo glow ?
https://www.youtube.com/watch?v=LaB1Iyq6Dk8


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 Post subject: Re: 120v to 4800 v transformer
PostPosted: Mon Jan 09, 2017 5:05 pm 

Joined: Fri May 10, 2013 12:55 pm
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dacflyer wrote:
most likely it is not a MOT, as 10Ma. is nothing..
most likely it is a transformer used in a bug zapper,,
i have come across many of them at that voltage and Ma. range..
i have some 5ft tall commercial bug zappers made by Flintrol, had 4ft black lights in them.
usually either the ballast or zapping transformer was bad.. i beefed em up with 5kv @ 30ma ( neon transformers )
watchem bugs splode.. bug zappers had a catch try under them, and after a good night of zapping, the tray would be 1/2 full..

transformer could also have possibly been used in a tube amp or transmitter ??

looking at the posted pic.. i seen something like that before, but it was in a super old B&W tv set, that had a neon tube around the CRT.
not sure but i think it was 1950's sylvania halo glow ?
https://www.youtube.com/watch?v=LaB1Iyq6Dk8



Neon around the picture tube? Oh boy. Imagine how annoying. And blue too.


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 Post subject: Re: 120v to 4800 v transformer
PostPosted: Mon Jan 09, 2017 5:09 pm 

Joined: Fri May 10, 2013 12:55 pm
Posts: 9
I live in a crowded urban area in NJ, so not a lot of bugs to massacre.
Well, it causes a florescence lamp to glow when near the transformer.

Do you think the 10mA is rating for the 4.8kv winding or the 120v winding?


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 Post subject: Re: 120v to 4800 v transformer
PostPosted: Mon Jan 09, 2017 6:04 pm 
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We're getting there!
It's common practice to rate the secondary side current, since that's what is required for the load.
In the simplest math, your transformer winding is 1:40 ratio (120:4800) and the secondary will provide 48 watts (E*I) (4800 * .010)
The primary wattage will also be 48 watts, but the current will be 0.4A. or 400ma (again, a 40:1 ratio)
In actuality, the primary current will be higher than this simple math because of several losses in the transformer, so the primary current must be compensate for them.

Also remember that transformers are rated at their load, so, if you measured 4800 open circuit, It will drop when supplying the 10ma. and this math will be off!

If this is a zapper transformer, it should be inherently current limiting, with high impedance windings, since a carbonized bug could exceed the transformer rating and aside from the bug,
it would let the smoke out of the transformer!

It's been a loooong time...Corrections and comments are welcomed!



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 Post subject: Re: 120v to 4800 v transformer
PostPosted: Tue Jan 10, 2017 12:09 pm 

Joined: Fri Aug 22, 2003 12:01 am
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1. He said in post 1 the 120V winding was 10mA.

2. For the amount of iron, 1.2W makes more sense than 48W.(see left side of photo in post 3)



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 Post subject: Re: 120v to 4800 v transformer
PostPosted: Tue Jan 10, 2017 12:17 pm 
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have seen many transformers used in bug zappers,, the bugs don't last long enough to kill a transformer,, they might fry a few seconds,,but there is usually a high voltage cap in parallel, so it makes a cleaner stronger spark, and snaps, rather than sizzling.


also the neon tube on them tv's was actually a color of cold white NEON called "Snow White" ( i used to make neon signs )

and most HV transformers i ever came across , the secondary Ma. was always listed,, (on neon transformers)
the neon transformers i came across were typically 30ma. and some rare 60Ma. but they were bout the size of a car battery almost
(15,Kv)


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 Post subject: Re: 120v to 4800 v transformer
PostPosted: Tue Jan 10, 2017 1:44 pm 
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Yes, he said the current was 10ma, but that number as is the other information, is hand written on the transformer, not factory stamped, and how it was determined is unknown.

To establish some values, it would be reasonable to load the transformer secondary until 10ma is reached then check the secondary voltage and primary current while watching the temperature rise on the transformer.

I Googled bug zappers and "Flintrol model 8599 label list sec. voltage 4000v 9Ma" popped up.
That's a bit too close for a coincidence.



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“To invent, you need a good imagination and a big pile of junk.” (T. Edison)
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 Post subject: Re: 120v to 4800 v transformer
PostPosted: Tue Jan 10, 2017 10:13 pm 

Joined: Fri May 10, 2013 12:55 pm
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umm...yah, I wrote those numbers when I was 19 years old....that was over 25 years ago...
Anyway, again, I got it at some junky shop that sold old electronics. But it was 10ma somewhere.
I have small children who are interested in the glowing florescence lamps. Maybe I'll propel something with the high voltage via static?
Of course, they're small children, so maybe I should put it away.


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 Post subject: Re: 120v to 4800 v transformer
PostPosted: Thu Jan 12, 2017 11:46 am 
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If you have access to a variable AC supply, ramp up the primary voltage while watching the secondary voltage to confirm the markings. Maybe a Variac? Even a lamp dimmer would give some idea of the markings veracity. Measure RMS in and RMS out.


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 Post subject: Re: 120v to 4800 v transformer
PostPosted: Thu Jan 12, 2017 12:16 pm 
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Also use a incandescent lamp in series with the transformer primary. Start low, then go high in wattage.
I use a simple box with a switch, lamp socket, and a standard recptacle. The swirch selects off, full or limited power. I do shop repairs on a switch mode ballast for phototherapy and over the years this box has saved a bucket full.of fuses. It"s a simple test; With a 200 w lamp, dim is good and the ballast works, bright there is a short and off is something open.
This was often used years ago with plug fuses to find shorts
Better stock up on the lamps before they go on the endangered species list. :sad:



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