Filament winding wire diameter

Klimon · 28th March 2010, 09:29 PM

What wire diameter should I use for adding a 3A filament winding to a power xfmr? The load requires 6,3 volts (=20 turns).

Thanks!!

Simon

azazello · 28th March 2010, 09:44 PM

You can calculate.....2.5 A for 1 sq. cm.

Richard Ellis · 28th March 2010, 09:49 PM

Here is one that I found. Max values.
Solid core, 0.6mm @ 1.5A
1mm @ 3A
1.7mm @ 4.5A
2mm @ 6A
That is diameter of the conductor, there are American Gauge to Millimeter conversion tables available.
Doing a two to one safety margin I would opt for the 2mm version for your 3A load.

__________________________________________________ ________Rick....

Klimon · 29th March 2010, 06:05 AM

Thank you. Are the quoted values for OFC? If not, am I right to suppose that ~1/2 diameter thickness should suffice given OFC's lower resistance?

PS Not trying to be difficult, just trying to use parts on hand!

Happy building

Simon

Richard Ellis · 29th March 2010, 02:25 PM

The values I found are from 'Morgan Jones, Valve amplifiers First edition?' Morgan Doesn't cite a footnote for these values so I will assume the "standard", 'common' copper conductors. Forgive me my ignorance but is OFC 'Oxygen free conductor'??? I thought "Oxygen free" refers to the insulation cladding being applied in an oxygen free environment. An attempt to keep the conductor/insulator interface from acquiring corrosion. As such does it have a "better" conducting value keeping conductor values constant?
I think there are other factors at play when winding different diameter windings independent of turns.....not to mention filling up the "window" in the I/E frame.

__________________________________________________ _____Rick....

AndrewT · 03:15 PM

transformers are often wound with copper areas that give ~3A/sqmm

on this basis :
1mm diam= 0.785sqmm = 2.4Aac.
1.4mm diam = 1.54sqmm = 4.7Aac.
1.6mm diam = 2.01sqmm = 6Aac.
2mm diam = 3.14sqmm = 9.4Aac.

The resistance of pure copper is near enough the same as oxygen free copper.
The area required for the same voltage drop and for the same power dissipation is the same.

Klimon · 29th March 2010, 07:56 PM

Quote:

Originally Posted by Richard Ellis

The values I found are from 'Morgan Jones, Valve amplifiers First edition?' Morgan Doesn't cite a footnote for these values so I will assume the "standard", 'common' copper conductors. Forgive me my ignorance but is OFC 'Oxygen free conductor'???
I think there are other factors at play when winding different diameter windings independent of turns.....not to mention filling up the "window" in the I/E frame.

__________________________________________________ _____Rick....

Should have checked with old Morgan...

Oxygen-free copper - Wikipedia, the free encyclopedia

@ Andrew: thanks a lot! This is very helpful

Cheers - Simon

28th March 2010, 09:29 PM	#1
Klimon diyAudio Member Join Date: Apr 2005 Location: Leuven	Filament winding wire diameter What wire diameter should I use for adding a 3A filament winding to a power xfmr? The load requires 6,3 volts (=20 turns). Thanks!! Simon

29th March 2010, 03:13 PM	#6
AndrewT diyAudio Member Join Date: Jul 2004 Location: Scottish Borders	transformers are often wound with copper areas that give ~3A/sqmm on this basis : 1mm diam= 0.785sqmm = 2.4Aac. 1.4mm diam = 1.54sqmm = 4.7Aac. 1.6mm diam = 2.01sqmm = 6Aac. 2mm diam = 3.14sqmm = 9.4Aac. The resistance of pure copper is near enough the same as oxygen free copper. The area required for the same voltage drop and for the same power dissipation is the same. __________________ regards Andrew T. Last edited by AndrewT; 29th March 2010 at 03:15 PM.

Thread Tools	Search this Thread
Show Printable Version Email this Page	Search this Thread: Advanced Search

Similar Threads
Thread	Thread Starter	Forum	Replies	Last Post
Raising filament winding above cathode with a EZ81 in the circuit OK?	G	Tubes / Valves	3	15th May 2008 08:29 PM
Taking a Hammond 369BX filament winding to the limit?	G	Tubes / Valves	3	15th January 2008 04:25 PM
Grounding the Filament Winding	alexmoose	Tubes / Valves	14	8th June 2006 03:39 PM
winding wire	Lostcause	Parts	3	3rd November 2005 01:50 AM
Help with lowering filament winding voltage.	G	Tubes / Valves	7	8th September 2003 11:36 PM

New To Site?	Need Help?
Register to Participate Search Privacy Statement Contact Us	Frequently Asked Questions Did you forget your password? Mark Forums Read

28th March 2010, 09:44 PM	#2
azazello diyAudio Member Join Date: Aug 2008 Location: Bulgaria	You can calculate.....2.5 A for 1 sq. cm.

28th March 2010, 09:49 PM	#3
Richard Ellis diyAudio Member Join Date: Sep 2006 Location: Mar del Plata, a BIG seasonal getaway city, can see the Ocean from our residence.	Here is one that I found. Max values. Solid core, 0.6mm @ 1.5A 1mm @ 3A 1.7mm @ 4.5A 2mm @ 6A That is diameter of the conductor, there are American Gauge to Millimeter conversion tables available. Doing a two to one safety margin I would opt for the 2mm version for your 3A load. __________________________________________________ ________Rick....

29th March 2010, 06:05 AM	#4
Klimon diyAudio Member Join Date: Apr 2005 Location: Leuven	Thank you. Are the quoted values for OFC? If not, am I right to suppose that ~1/2 diameter thickness should suffice given OFC's lower resistance? PS Not trying to be difficult, just trying to use parts on hand! Happy building Simon

29th March 2010, 02:25 PM	#5
Richard Ellis diyAudio Member Join Date: Sep 2006 Location: Mar del Plata, a BIG seasonal getaway city, can see the Ocean from our residence.	The values I found are from 'Morgan Jones, Valve amplifiers First edition?' Morgan Doesn't cite a footnote for these values so I will assume the "standard", 'common' copper conductors. Forgive me my ignorance but is OFC 'Oxygen free conductor'??? I thought "Oxygen free" refers to the insulation cladding being applied in an oxygen free environment. An attempt to keep the conductor/insulator interface from acquiring corrosion. As such does it have a "better" conducting value keeping conductor values constant? I think there are other factors at play when winding different diameter windings independent of turns.....not to mention filling up the "window" in the I/E frame. __________________________________________________ _____Rick....

Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)