No. of Turns (Transformers)

Bane · Apr 17, 2009

Hi people,

I apologise if this question has come up before. I've obviously overlooked it whilst perusing the library.

Is there a formulae for working out Number of Turns (Primary and Secondary) with only the following available data:

Input (VA)

Output (VA)

Primary Current

Secondary Current

Primary Voltage

Secondary Voltage

Resistance

Efficiency

I've come to the conclusion that there isn't but I shall trust myself to your better judgement.

Andy™ · Apr 17, 2009

Bane · Apr 17, 2009

Thanks Andy but transposing that formula still entails me needing at least one value of turns on either primary or secondary.

Ns= Us x Np/Up

Np= Up x Ns/Us

SPECIAL LOCATION · Apr 17, 2009

Because the number of turns primary & secondary are proportional with each other, you have to have one of them to know what the other is going to be.

simple example:

consider a shaver socket isolating transformer.. 1:1 no step up or down!

Vp = Vs e.g. 230v

Ip = Is say <1amp

Np = Ns pick a number?

if you have 200 turns primary you must have 200 turns secondary

if you have 400 turns primary you must have 400 turns secondary

if you have 127 turns primary you must have 127 turns secondary

if you have 50,000 turns primary you must have 50,000 turns secondary

if you have 73 turns primary you must have 73 turns secondary

The actual quantity will be more in relation to the gauge of the wire used to manufacture the transformer, its resistance, and how big the whole assemble has to be to it into the manufactures housing.

In a step up or step down arrangement the proportional relationship still has to apply so the transformer manufacture would have to decide upon one to them to select the correct number for the other winding.

hope that helps..Guiness DrinkGuiness DrinkGuiness Drink