need to build a transformer.... point me in right direction?

AudioGeek · 4th February 2005, 03:33 AM

hey,

I am looking to build a simple transformer with 2 primary windings and one secondary winding.

ratio of 1:2 for primary 1 and 1:2 for primary 2...

so essentially quadfilar wound i guess?

oh an no DC on core.. actually there will be DC but the second primary winding is there to null or offset the DC...

make sense?

problem is, what core size, what wire thickness, and how many total turns?

any primers out there? or anyone can help me?

oh... this is all like less than 10v on these transformers. for a pre-amp.

Thanks!!!

AndrewT · 4th February 2005, 12:45 PM

Hi,
I have just re-read your Q.
I do not know what you intend doing with the result.
Is it mains frequency or audio frequency?
Is power or driver?
What power/current/impedance do you expect.
I will not be able to answer your Q but do try to give your potential respondents a chance.
regards Andrew T.

jacco vermeulen · 4th February 2005, 07:26 PM

You can always read a book on transformers.
Menno vanderVeen has written one, you can find his stuff at the Plitron site.

Eva · 5th February 2005, 01:37 AM

These three sentences may help you to better understand transformers :

- For a given core and keeping the frequency constant : The number of primary turns is proportional to the maximum voltage it has to withstand without saturating

- For a given core and keeping the voltage constant : The number of primary turns is proportional to the inverse of the minimum frequency it has to withstan without saturating [1/F]

- Keeping the voltage and the frequency constant, the minimum number of primary turns required to avoid saturation decreases as core size is increased

So essentially you have to find a core size that allows a reasonable minimum primary turn count for your minimum frequency and maximum voltage requirements

You may also think in terms of :
max.voltage / (frequency * turns) = constant

[And this constant increases with core size. Note that the voltage capability increases with frequency]

Note that this is a drastic simplification, there are a lot of parameters to consider in transformer design

4th February 2005, 03:33 AM	#1
AudioGeek diyAudio Member Join Date: Jan 2004 Location: Minnesota	need to build a transformer.... point me in right direction? hey, I am looking to build a simple transformer with 2 primary windings and one secondary winding. ratio of 1:2 for primary 1 and 1:2 for primary 2... so essentially quadfilar wound i guess? oh an no DC on core.. actually there will be DC but the second primary winding is there to null or offset the DC... make sense? problem is, what core size, what wire thickness, and how many total turns? any primers out there? or anyone can help me? oh... this is all like less than 10v on these transformers. for a pre-amp. Thanks!!! __________________ It is not you... you are it.

4th February 2005, 07:26 PM	#3
jacco vermeulen diyAudio Member Join Date: Oct 2004 Location: At the sea front, Rotterdam or Curaçao	You can always read a book on transformers. Menno vanderVeen has written one, you can find his stuff at the Plitron site. __________________ Not so much,.......if it says "ZM" in the corner.

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4th February 2005, 12:45 PM	#2
AndrewT diyAudio Member Join Date: Jul 2004 Location: Scottish Borders	Hi, I have just re-read your Q. I do not know what you intend doing with the result. Is it mains frequency or audio frequency? Is power or driver? What power/current/impedance do you expect. I will not be able to answer your Q but do try to give your potential respondents a chance. regards Andrew T.

5th February 2005, 01:37 AM	#4
Eva diyAudio Member Join Date: Oct 2003 Location: Near the sea	These three sentences may help you to better understand transformers : - For a given core and keeping the frequency constant : The number of primary turns is proportional to the maximum voltage it has to withstand without saturating - For a given core and keeping the voltage constant : The number of primary turns is proportional to the inverse of the minimum frequency it has to withstan without saturating [1/F] - Keeping the voltage and the frequency constant, the minimum number of primary turns required to avoid saturation decreases as core size is increased So essentially you have to find a core size that allows a reasonable minimum primary turn count for your minimum frequency and maximum voltage requirements You may also think in terms of : max.voltage / (frequency * turns) = constant [And this constant increases with core size. Note that the voltage capability increases with frequency] Note that this is a drastic simplification, there are a lot of parameters to consider in transformer design