Help my transformer getting hot quickly - diyAudio
Go Back   Home > Forums > Amplifiers > Power Supplies

Please consider donating to help us continue to serve you.

Ads on/off / Custom Title / More PMs / More album space / Advanced printing & mass image saving
Reply
 
Thread Tools Search this Thread
Old 30th December 2005, 10:06 PM   #1
diyAudio Member
 
Join Date: Dec 2004
Location: Jakarta
Send a message via Yahoo to darw82
Default Help my transformer getting hot quickly

I build a push pull converter.
(10V - 15V) to 12V. 120Watts

Everything works very well. Only the transformer. It getting hot very quickly, with only 30W load.

The transformer is
TC-42212 from Mag-Inc.

Ae=0.511 cm2
WaAc=0.756 cm4
Ve=2.77 cm3

Primary winding 4 + 4.
Secondary winding 6 + 6

What's the problem? Can anybody tell me?

Thanks
  Reply With Quote
Old 30th December 2005, 10:29 PM   #2
Danko is offline Danko  Hungary
diyAudio Member
 
Join Date: Apr 2004
Location: Hungary
Hi!


What is the switching frequency?

Have you tried increasing the primary turns?
__________________
Best regards, Danko
  Reply With Quote
Old 30th December 2005, 10:54 PM   #3
diyAudio Member
 
Join Date: Dec 2004
Location: Jakarta
Send a message via Yahoo to darw82
Danko,
The switching frequency is 100Khz.

I have tried increasing the winding.
primary (8 + 8 )
secondary (12 + 12)

But it's still very hot with light loading.
  Reply With Quote
Old 30th December 2005, 11:03 PM   #4
Danko is offline Danko  Hungary
diyAudio Member
 
Join Date: Apr 2004
Location: Hungary
Hi!

What kind of wire(s) do you use?
__________________
Best regards, Danko
  Reply With Quote
Old 30th December 2005, 11:05 PM   #5
diyAudio Member
 
Join Date: Dec 2004
Location: Jakarta
Send a message via Yahoo to darw82
Danko, thanks for your help.

The wire for primary and secondary is (0.4mm * 4)
  Reply With Quote
Old 30th December 2005, 11:14 PM   #6
Danko is offline Danko  Hungary
diyAudio Member
 
Join Date: Apr 2004
Location: Hungary
The 4x0.4mm wire seems a little bit too small, for me.

I designed an SMPS, which operated from 50VDC, and the primary current was about 6-8A. A wound the primary from 17-18 piece of 0.4mm wire.

You write, that output power is 120W, from 12V. That's 10A.

Try increasing the number of the wires. One single wire's diameter is good, becouse at 100kHz the penetration depth is about 0.21mm. Skin-effect rules :-)
__________________
Best regards, Danko
  Reply With Quote
Old 30th December 2005, 11:37 PM   #7
Eva is offline Eva  Spain
diyAudio Member
 
Eva's Avatar
 
Join Date: Oct 2003
Location: Near the sea
Send a message via MSN to Eva
Do you mean a 100Khz oscillator, or a 100Khz effective frequency through a 200Khz oscillator?
  Reply With Quote
Old 30th December 2005, 11:47 PM   #8
diyAudio Member
 
Join Date: Dec 2004
Location: Jakarta
Send a message via Yahoo to darw82
Eva,
The controller is SG3524. Running at 200khz.
In push pull mode, this IC will divide the frequency. so it would be 100Khz effective frequency through a 200Khz oscillator
  Reply With Quote
Old 31st December 2005, 12:54 AM   #9
amp_cy is offline amp_cy  Cyprus
diyAudio Member
 
Join Date: Dec 2005
Location: Nicosia
Please supply complete code number, there should be several other characters which will inform you of the material type. If there is a J or W or an H, these stand for 6040u, 12080u and 18100u permeability respectively. This type of core are suitable for common mode chokes, broadband transformers, pulse transformers and current transformers.
If there is a R or P or an F, these stand for 2770u, 3020u and 3624u permiability respectively. This type of core is good for high frequency transformers, i.e. your application.

If you have one of the very high permiablity cores J,W or H, you have a very good chance that you are saturating the core if your ON period is long enough (what is your operating frequency?). Check the current waveforms at the switching devices, if there is a large exponentinal peak (looks like a spike), you are saturating the core if this is the case.
You could have a flux imbalance problem, are you using current mode control or a series pass capacitor on the center tap of your primary?

More data is needed to solve your problem, send the complete core code, control method and operating frequency.

P.s. check this page for data sheets on you core. http://www.mag-inc.com/ferrites/fc601.asp
  Reply With Quote
Old 31st December 2005, 02:45 AM   #10
Eva is offline Eva  Spain
diyAudio Member
 
Eva's Avatar
 
Join Date: Oct 2003
Location: Near the sea
Send a message via MSN to Eva
Calculations show 100mT peak for 12V, 6 turns and 100Khz effective (Ae=0.51cm^2). This shuld be ok for most materials so the problem may be due to flux imbalance.
  Reply With Quote

Reply


Hide this!Advertise here!
Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
How do you locate active forums quickly? peace brainerd Everything Else 4 29th June 2007 12:18 AM
wanted quickly!!!! a circuit to convert mono to stereo. sagarverma Analog Line Level 4 10th May 2006 11:06 AM
Sonotube sub = goes up in flames quickly eRiCdWoNg Everything Else 8 12th April 2004 03:08 AM


New To Site? Need Help?

All times are GMT. The time now is 03:54 PM.


vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2014 DragonByte Technologies Ltd.
Copyright 1999-2014 diyAudio

Content Relevant URLs by vBSEO 3.3.2