Generators and Electric Motors
[Home] - [HELP] - [Forums] - [Groups] - [Classified Ads] - [Subscribe] - [Books] - [Sponsors] -

Go Back   SmokStak > SmokStak® Shop Equipment Tools and Techniques > Welding Shop
Forgot Password? Join Us!

Notices

Welding Shop Welder generators, equipment, weld practice, techniques, troubles and solutions. See our TERMS of SERVICE prior to reading!

Welding Shop

How does an AC stick welder current control work?


this thread has 1 replies and has been viewed 5324 times

Reply
 
Thread Tools Display Modes
  #1  
Old 09-18-2009, 12:04:11 PM
systemloc systemloc is offline
Registered
 
Join Date: Sep 2009
Location: Tampa, FL
Posts: 1
Thanks: 0
Thanked 0 Times in 0 Posts
Default How does an AC stick welder current control work?

I've looked everywhere for a proper schematic for anything similar to a Lincoln AC-225 tombstone. Can anyone explain how the current selection control works? Is it simply switching between more and less turns on the secondary winding?

I'm wondering, if this is the case, how this affects the no-load voltage. At low current settings, the voltage would be low and it would be more difficult to strike a spark.

The reason I'm asking is for info on building something similar to an AC-225 using microwave transformers ala Dansworkshop.com, but I don't care to play with SCR's for current control.
Reply With Quote
Sponsored Links
  #2  
Old 09-18-2009, 11:54:43 PM
KEB KEB is offline
Registered
 
Join Date: Jul 2007
Location: Parker, Colorado USA
Posts: 119
Thanks: 0
Thanked 64 Times in 41 Posts
Default Re: How does an AC stick welder current control work?

The current control is built into the transformer. As far as I know, there are two methods, one involving a variable reactance (inductor) and one varying the magnetic flux (coupling) between the primary and secondary windings.

The variable coupling approach is easier to understand...it's accomplished by moving a piece of metal in and out of the transformer. The open circuit voltage is determined by the ratio of the primary and secondary windings, and the current is controlled by how much magnetic coupling there is between winding. Variable reactance transformers use multiple taps on an additional (I think) winding on the transformer to control coupling.

I don't have all the design data in front of me to look at this in detail, but basically these are special transformers. That's why some other sort of current control, i.e, SCRs, is required with other types of transformers.

I understand that microwave transformers are current limited, not constant current. In this case, the current limiting is accomplished by shunting some of the magnetic coupling between the primary and secondary windings.

If you're looking for a working welder, try Craigslist. AC buzzbox type welders routinely show up in this area for less than $100, and I've seen a few in the $50 range. If you're looking for a fun project, hope this info helps.

Keith
Reply With Quote
Reply

Bookmarks


Thread Tools
Display Modes

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

F o r u m Jump

Similar Threads Chosen at Random
Thread Thread Starter F o r u m Replies Last Post
Airco Dip/stick 160 PFT Welding Shop 11 02-06-2010 09:02:01 PM
Why stick with slow speed? Mike S Hit & Miss Gas Engine Discussion 19 12-03-2008 06:29:38 PM
fire stick Dick-CT Hit & Miss Gas Engine Discussion 4 08-16-2008 04:22:17 PM
Help: 6 cylinder 3KW generator/stick welder rcmule76 Welding Shop 0 01-14-2007 09:48:29 PM
How do you get the decals to stick! Tim Claremont Antique Engine Archives 11 12-10-2001 12:48:50 AM


Use "Ctrl" mouse wheel to change screen size.
All times are GMT -4. The time now is 06:23:52 PM.

Smokstak and Enginads site search!


All use is subject to our TERMS OF SERVICE
SMOKSTAK® is a Registered Trade Mark - A Community of Antique Engine Enthusiasts
Copyright © 2000 - 2019 by Harry Matthews P.O. Box 5612 - Sarasota, FL 34277