Power transformer design question

General discussion area for tube amps.

Moderators: pompeiisneaks, Colossal

Post Reply
User avatar
gui_tarzan
Posts: 606
Joined: Thu Jan 16, 2014 3:10 am
Location: The 26th State

Power transformer design question

Post by gui_tarzan »

Why do the windings have square bobbins? Why not use round bobbins? It seems it would be a whole lot easier to wind them. Yes, this is a serious question. :)
--Jim

"He's like a new set of strings, he just needs to be stretched a bit."
SilverFox
Posts: 222
Joined: Fri Feb 10, 2012 6:03 pm

Just a guess

Post by SilverFox »

Likely it was easier to manufacture the square plate E sections; Less waste material. A circular cutter would be harder to sharpen and keep sharp back then. That's what I think.

silverfox
John_P_WI
Posts: 1456
Joined: Wed Aug 15, 2007 4:29 pm
Location: Wisconsin

Re: Power transformer design question

Post by John_P_WI »

Because the laminates are shaped like an E that are slid in from both side of the bobbin. If the bobbin was round, the shape of the laminate would have to change as they move off of the hole axis, resulting in extra laminate tooling and complexity assembling. The square bobbin and flat laminates can be assembled tightly with minimum spacing for best efficiency.
User avatar
Dr-Joned
Posts: 224
Joined: Thu Dec 13, 2007 9:43 pm
Location: The Great South, USA

Re: Power transformer design question

Post by Dr-Joned »

Google "R core" transformers. They have been around a long time and are more efficient than your standard E I core tranny. I haven't done a lot of research, but they look to be easier to wind. They come in sort of a humbucking configuration.
I Think I Think Too Much !
User avatar
TUBEDUDE
Posts: 1656
Joined: Thu Jan 04, 2007 5:23 pm
Location: Mastersville

Re: Power transformer design question

Post by TUBEDUDE »

Or "C" core trannies.
Tube junkie that aspires to become a tri-state bidirectional buss driver.
User avatar
JMFahey
Posts: 252
Joined: Sun Dec 13, 2009 1:39 pm
Location: Buenos Aires - Argentina

Re: Power transformer design question

Post by JMFahey »

Standard procedure to build a transformer core (which is EI) starts with such shapes punched out of flat sheet.

Since all EI are the same size, stacking them creates a rectangular core.

A Toroid or a C core still have a rectangular core, because they are made by winding a silicon steel ribbon; obviously making it constant width is the cheapest most efficient way.
Post Reply