FAQFAQ   GalleryGallery   SearchSearch   MemberlistMemberlist   UsergroupsUsergroups   RegisterRegister 
 ProfileProfile   Log in to check your private messagesLog in to check your private messages   Log inLog in   Forum RSS Feed   Hacked Gadgets Main Site 

Need Help With A Special Mini Spot Welder

 
Post new topic   Reply to topic    Hacked Gadgets Forum Index -> New Projects Currently Being Developed
View previous topic :: View next topic  
Author Message
havlicek
Newbie


Joined: 28 Nov 2008
Posts: 4

PostPosted: Fri Nov 28, 2008 2:55 pm    Post subject: Need Help With A Special Mini Spot Welder Reply with quote

I've been trying to gather information to build a welder for a special application. The use is for welding the commutator tabs and magnet wire that passes over them for small DC motors. While there are specialized and often automated welders made for this purpose, they are both large and very expensive and really intended for industrial users. I have been able to get small bits of information as to how others have done this, but it's been difficult to get the whole project laid out. The materials being welded (soldering isn't a preferable way to make this connection both because of the extreme high speed and heat these motor armatures experience) are the brass commutator tabs (approximately .030" thick material about .060" wide formed as a "U") and the copper magnet wire used to wind the poles that then passes over each brass tab...from #23 awg to #28awg.
From what I've been able to gather, people have done this on a "homebrew" basis using 6V automotive battery chargers/starters that can deliver around 30 amps or more. I have very little knowledge of electronics and none at all about welding and circuit design, but am looking for information on how I might proceed after sourcing the charger/starter. I'm guessing that the "negative" cable would be adapted to use as a clamp at the commutator and would also double as a heat sink to prevent damaging the commutator and that the "positive" cable would somehow be adapted to hold some sort of fine rod that would touch each com tab to complete the welds.

-Maybe a footswitch could or should be used to start/stop the weld?
-Is the positive cable simply used to hold a rod for the "spot weld"?, or are there other pieces that need to be added? To my mind, it would seem that simply touching the positive to the commutator tab to make the weld and complete the circuit would simply trip a breaker at the panel or any protection device on the charger(dead short!?).
-Any other information or thoughts?

Thank you in advance
-john
Back to top
View user's profile Send private message

Alan
Site Admin


Joined: 29 Jan 2006
Posts: 1399
Location: Winnipeg, MB

PostPosted: Sat Nov 29, 2008 1:25 pm    Post subject: Reply with quote

I have never built a welder (or spot welder) but I did find a site that has some information that should help.

http://www.5bears.com/welder.htm
Back to top
View user's profile Send private message Send e-mail
havlicek
Newbie


Joined: 28 Nov 2008
Posts: 4

PostPosted: Sat Nov 29, 2008 1:43 pm    Post subject: Reply with quote

Hi Alan and thanks for the link! I had seen that one beforehand but it really doesn't apply since fitting a small armature in precisely the correct position between the tips would be very difficult. I'm guessing that a small "stick" type welder of some sort would be best. Goofing around today, I did try some experiments. I have a variable power supply that will do up to 12 VDC at 15 amps and I clipped one of the output leads (-) to a piece of thin brass and the other lead (+) to several different diameter and length pencil leads. When contacting the brass with the + tip of the pencil lead (graphite), the supply would cuase a spark & turn the lead bright yellow hot after a second or so before the circuit protector would turn off the power supply. I imagine that with a more suitable tip and more current, something along these lines would probably do the job. It could be that even 15A at 12 or 6V is sufficient, but the power supply I have will just trip/reset when used this way. If anyone has any ideas of how to make this thing work, I sure would appreciate it. Thanks again Alan.

-john
Back to top
View user's profile Send private message
Display posts from previous:   
Post new topic   Reply to topic    Hacked Gadgets Forum Index -> New Projects Currently Being Developed All times are GMT - 6 Hours
Page 1 of 1

 
Jump to:  
You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum



Powered by phpBB © 2001, 2005 phpBB Group