[ask] calculating ampere in toroidal transformers - diyAudio
 [ask] calculating ampere in toroidal transformers
 User Name Stay logged in? Password
 Home Forums Rules Articles diyAudio Store Gallery Wiki Blogs Register Donations FAQ Calendar Search Today's Posts Mark Forums Read Search

 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
 22nd September 2013, 06:29 PM #1 diyAudio Member   Join Date: Feb 2012 [ask] calculating ampere in toroidal transformers hi guys, i have a toroidal rated at 500watt there are 4 output secondary: 0-48 0-48 0-36 0-36 0-24 0-24 0-18 0-18 assuming Watt=Volt x Ampere, so if calculating from 48v > 500watt/2x48=5,2A 36v > 500watt/2x36=6,9A 24v > 500watt/2x24=10,4A 18v > 500watt/2x18=13,9A does anyone know how to calculate properly? i mean, what is the real current for 500watt toroidal transformer? thanks. __________________ Aleph 30, Aleph P1.7, Pass F5, B1 Buffer, Aleph J, Pumpkin PreAmp, TDA1541 DAC http://poshaudio.blogspot.com
 22nd September 2013, 08:57 PM #2 diyAudio Member   Join Date: May 2007 With multiple secondaries you can't tell, as there is no easy way of determining exactly how the designer apportioned his available VA among them. You may be able to get a rough idea by measuring their resistance - but measuring low resistances accurately is not easy.
 22nd September 2013, 09:34 PM #3 diyAudio Moderator R.I.P.   Join Date: Nov 2005 I would say more likely like this (rough estimate) 0-48 0-48, 5A (x2) 0-36 0-36, 3A 0-24 0-24, 2A 0-18 0-18, 1A __________________ sometimes we know very little, and sometimes we know too much
 22nd September 2013, 10:20 PM #4 diyAudio Member   Join Date: Jan 2003 Location: mississauga ontario canada Manufacturer? Part number? Picture? __________________ Doug We are all learning...we can all help "You can't stop the signal, Mal. Everything goes somewhere..."
diyAudio Member

Join Date: Sep 2009
Quote:
 Originally Posted by wengtech hi guys, i have a toroidal rated at 500watt there are 4 output secondary: 0-48 0-48 0-36 0-36 0-24 0-24 0-18 0-18 assuming Watt=Volt x Ampere, so if calculating from 48v > 500watt/2x48=5,2A 36v > 500watt/2x36=6,9A 24v > 500watt/2x24=10,4A 18v > 500watt/2x18=13,9A does anyone know how to calculate properly? i mean, what is the real current for 500watt toroidal transformer? thanks.
You are mixing Watts and Volt-Amps as if they were the same, they are certainly not. You must consider power factor. If you feed an AC winding into a full wave bridge, the DC load current available is only about 0.6 times the AC RMS current rating of the transformer secondary.

BTW:

Quote:
 i have a toroidal rated at 500watt
Impossible. The transformer can not be rated in watts, it is V-A.

 23rd September 2013, 07:48 AM #6 diyAudio Member     Join Date: Jun 2007 Location: Romania Electric power transformer is specified in VA (apparent power = volts X amps). Depending on the rectifier used, the DC power available is much less than the apparent power. a) if the four windings of the transformer isn't separated galvanically, then winding rated current is calculated as follows: I = Power / Voltage = 500 / (2 x 48) = 5.20 amps. So, in such a case, all the windings of the transformer can be loaded with a maximum of 5.20 amps. To learn if the transformer is in this situation, you must measurement all sections winding conductors. If sections conductors are identical, then you are in this case, if not, see case b below. b) This case applies when the windings are galvanically separated. Measurement section conductors can provide us an idea about the current values ​​that can be charged by them, with the condition that relate to a certain current density (eg 3A/mmp). I can make you a concrete answer to this question but you need tell me the diameter of each winding conductor. __________________ AV400v2 and GX400 audio amplifier projects PCB Design Services - for prototypes OR serial products, Today Tehnium and Forums
 23rd September 2013, 10:19 AM #7 diyAudio Member   Join Date: Jul 2004 Location: Scottish Borders Don is right. You must check if there is: one winding with lots of taps or two windings with lots of taps or many windings with no intermediate taps. Can you see thickness of the wire in each tap and end? This can be a good guide to current rating. __________________ regards Andrew T. Sent from my desktop computer using a keyboard
 23rd September 2013, 10:57 AM #8 diyAudio Member   Join Date: Dec 2001 Location: South Sweden I agree with previous posts. check wether it is one winding with several taps or wether it is separate windings. measure thickness to get an idea about current handling. forget about resistance measurment unless you have a low R meter. __________________ listen! Can you hear that ...
 23rd September 2013, 02:21 PM #9 diyAudio Member   Join Date: Feb 2012 hi... thanks for comment. this is the sample pictures of toroidal i mean. this one rated 500W with multiple secondary diameter 14cm height 8cm weight 4kg what do you think.? __________________ Aleph 30, Aleph P1.7, Pass F5, B1 Buffer, Aleph J, Pumpkin PreAmp, TDA1541 DAC http://poshaudio.blogspot.com
 23rd September 2013, 02:41 PM #10 diyAudio Member     Join Date: Jun 2007 Location: Romania @wengtech, I asked you to tell us diameter wires, not the transformer size. __________________ AV400v2 and GX400 audio amplifier projects PCB Design Services - for prototypes OR serial products, Today Tehnium and Forums

 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 OffTrackbacks are Off Pingbacks are Off Refbacks are Off Forum Rules

 Similar Threads Thread Thread Starter Forum Replies Last Post juggler73 Power Supplies 3 28th May 2010 05:08 AM walker Solid State 43 15th September 2006 02:21 PM muddy Class D 3 24th February 2005 11:23 PM Rixsta Pass Labs 10 23rd April 2004 03:41 AM jhead Chip Amps 3 8th March 2004 07:58 AM

 New To Site? Need Help?

All times are GMT. The time now is 04:33 PM.