transformer winding

gearheadgene · 13th November 2008, 11:50 AM

After running through the math, I find I require the following number of turns:

Primary: 11.48 Turns
Secondary #1 : 1 Turn
Secondary #2 : 4.5 Turns
Secondary #3 : 4.5 Turns

This is planned for a torroid (kool u) in a DCM flyback. Those 4.5 turns maybe should be rounded down, and maybe that primary 11.48 as well. Is running 1 turn a problem?

Any body care to chime in a good method to wind it? There's not much to wind, so it's got to be pretty easy

gene

dtproff · 14th November 2008, 06:14 AM

FYI

The only way to get a half turn in a toroid is to drill a hole in the middleof the cor and pass the wire through.

Round up (not down) and let te duty cycle adjust the output votlage accordingly (it will pull in just slightly). Hope that helped.

Tony

poobah · 14th November 2008, 06:53 AM

Work with your tolerances... Input Voltage Minimum can be tweaked to yield a integer primary winding...

Likewise for the secondaries... you have no option regarding the ratios of the secondaries... but the total number of turns can ne altered with core choice or frequnecy. Secondaries with turn counts this low will cross-regulate very poorly unless you wind them mutifilar (strands in parallel) for each seperate secondary.

megajocke · 14th November 2008, 02:52 PM

Quote:

Originally posted by dtproff
FYI

The only way to get a half turn in a toroid is to drill a hole in the middleof the cor and pass the wire through.

If you were to do that it will have similar problems as trying to do half turns on an E-core without the extra loop in parallell around the other outer leg.

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13th November 2008, 11:50 AM	#1
gearheadgene diyAudio Member Join Date: Jul 2005 Location: CT	transformer winding After running through the math, I find I require the following number of turns: Primary: 11.48 Turns Secondary #1 : 1 Turn Secondary #2 : 4.5 Turns Secondary #3 : 4.5 Turns This is planned for a torroid (kool u) in a DCM flyback. Those 4.5 turns maybe should be rounded down, and maybe that primary 11.48 as well. Is running 1 turn a problem? Any body care to chime in a good method to wind it? There's not much to wind, so it's got to be pretty easy gene

14th November 2008, 06:14 AM	#2
dtproff diyAudio Member Join Date: Oct 2008 Location: Plano, TX, USA	FYI The only way to get a half turn in a toroid is to drill a hole in the middleof the cor and pass the wire through. Round up (not down) and let te duty cycle adjust the output votlage accordingly (it will pull in just slightly). Hope that helped. Tony

14th November 2008, 06:53 AM	#3
poobah diyAudio Member Join Date: Nov 2005	Work with your tolerances... Input Voltage Minimum can be tweaked to yield a integer primary winding... Likewise for the secondaries... you have no option regarding the ratios of the secondaries... but the total number of turns can ne altered with core choice or frequnecy. Secondaries with turn counts this low will cross-regulate very poorly unless you wind them mutifilar (strands in parallel) for each seperate secondary.