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# Trafo

Posted on 1997-10-01
Medium Priority
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Does anyone know were I can get some informations about
rewindind an trafo (how thick core and how many windings I
shal use)
0
Question by:hp080797
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LVL 3

Expert Comment

ID: 1025319
Hi
I think so this is not database question. This is Electrical Question. When you need rewind "trafo" (are you from poland ?) then you must know the power, current, voltage etc. This is more complicated as many people think. The beter way is to buy a book. Of course if you need only repair "trafo" :-) then you can count previous windings.
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Expert Comment

ID: 1025320
Mister hp:

Assuming that "trafo" is a transformer, a common electrical device, the public library is your best bet for finding a book that has the required info.  You needn't spend a dime until you know which books you want in your home all the time for immediate reference.

The ratio of windings in the Primary to windings in the Secondary is the same as the ratio of ac voltage in the Primary to the ac voltage in the secondary.

A quick example:

100  turns of wire in the Primary coil
1000 turns of wire in the Secondary coil

gives a tenfold (10 times) increase in ac voltage.  Secondary will output ten times the voltage that the Primary is supplied with.  Naturally, what with the rather _strict_ Law of Conservation of Energy, the current, or amperage, will _drop_ by the same exact ratio! There is also a small loss of energy in metallic (iron, steel, or ferrite) core transformers, but it isnt very much.  Less that 5-10% or else get a new one, that one has a short cicuit!

Another example:

110 volts ac into Primary.
Device is labelled 2000 volts output.

2000/110 = ratio of approximately 18.  Therefore the secondary should have 18 TIMES the number of turns as the primary has.  Note:  not 18 more turns, 18 times more turns!

You might be thinking that "Database Questions" refers to a large database of all human knowledge.  It really refers to questions people have about getting their software databases to work properly!

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Author Comment

ID: 1025321
Trafo=Transformer. It is very difficult to find an book about the subjekt, so please help me. I know that the quotient of primary windings and sekondary windings is equl the quotient of primary voltage and sekondary voltage, but how many windings should there be.
I am avere of, that this is'nt the rigth place to ask this question, but were is.

Pleace do forgive my spelling errors(and gramatics errors)

HP
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LVL 10

Accepted Solution

bret earned 1600 total points
ID: 1025322
You can probably find an informative book from Lindsay Publications, which specializes in technical manuals, and
particularly in reprinting old manuals and how-to books.

Among their current offerings, number 20030 "High Frequency Apparatus" (US\$12.95) appears likely to answer your questions.
The description reads "...wall-to-wall how-to on coil construction.  Tips on calculating windings, winding coils, making transformers (!), interrupters, and spark gaps..."

Lindsay Publications
PO Box 538
USA

USA-(815)-935-5353 (best to call in morning, USA time)

They are also online at http://www.keynet.net/~lindsay
(I have experienced long delays in connecting to this site).

If nothing else, get on their mailing list for their catalogs,
which are fascinating.  They do accept VISA and MASTERCARD.
I've ordered from them several times and have not been disappointed.

-bret

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Author Comment

ID: 1025323
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