Where can I learn how to design a transformer?

[TheMaster]

I have several times in the past needed to order custom transformers, and I may need to do so again in the near future.
I know/knew the required values from my transformer, and the desired package, though I have no clue how to determine the the construction details (windings, wires, core, etc...). This brings about a great deal of hassle as I have to wait for the supplier to do the designing, and they aren't typically excited to do so.

For instance, if I require a transformer of this EPC series, and I know my required inductances, ratio, voltages, currents, frequency, etc...
How can I go about learning how to design it? Is it exceptionally difficult or require expertise, or is something that can be learned with reasonable effort on the web?

-Thank you

 

[Arouse1973]

Just out of interest, what special about your project that requires a custom tranny.
Cheers
Adam

 

[TCSC47]

I presume you mean a power transformer. I've got a very old book, Coil Design and Construction Manual, Bernards Radio Manual No 160, dates from 1960 (!) but power transformers have not changed much, if any, which I once used to design and construct a transformer.
Guess who the editor was --- Clive Sinclair of ZX Spectrum or Timex Spectrum over there in the USA, fame. He used to have a proper job before making computers.

Many Radio Amature handbooks from the 50's and 60's have sections on the practicalities of making transformers.

Way back in the 70's I had to look after a number of laboratory analytical equipment. I had several power transformer failures but found a local winder in Coventry (UK) nearby who could produce me a custom made replacement for no more than an off the shelf one or rewind the transformer for even less. I don't know what the economics of making your own transformer compared to getting one specially made are now a days though but I would hope it would still be competitive.

This web site looks interesting. http://electronicdesign.com/power/build-your-own-transformer


and of course there is Utube

though I wasn't impressed with some of the utube makers safety procedures showing that he is an amature..

One thing I would always advise when making power supplies, and in particular power transformers, is that you take on a great responsibility when you do so. Remember that yours is a one off and there may be something you over looked or incorrectly calculated. This may lead to your power supply blowing up the much more valuable circuit that it is running, for the saving of a bit of cost of the power supply. However, much worse, you are dealing with lethal voltages and currents and if your transformer fails it may connect somebody to the mains supply with all the consequences involved! A commercial manufacturer of transformers or power supplies has made thousands of their products and ironed out all the problems.

 

[duke37]

Look up ludens transformer.

 

[TheMaster]

This is for a mobile accessory application, the requirement for a custom design stems from the need for specific values and a particular bobbin size. This is for a mass production unit.

Anyway, I'm beginning to get the impression that this is for the experts. I would imagine that the big firms do their designing with some specialty software; from the looks of it it seems really complex.

Out of curiosity, when most people order a custom transformer do they know what the design information should be? Or do they just give values...

*I will look at the links though, thanks

 

[TCSC47]

I simply specified input and output voltage and output current with 10% or so extra. Also the frequency of operation. I also had to specify the type of construction, E&I lamination or toroidal if I had to minimise magnetic leakage. And things like what sort of encapsulation, if any, and any tappings to allow for mains adjustments, and mounting dimentions. The transformer person will take you through it.