Dave,

To answer a few of your questions,

Yes the 'Silver thingie' and the 'blue thingie' are both medium sized caps.

No those are not rectifiers they are NPN Darlington transistors. I googled
the part number "PTC10021" which is printed on them and got several good
hits
go here for full specs...
http://www.americanmicrosemi.com/pro...PTC10021.phtml
FYI googeling part numbers is a good way to get info, you just have to wade
through places that want to charge for spec sheets.
The black 'thingies' next to them are heat sensors.

It looks like the only rectifiers are the ones on the mini circuit boards,
you are right the round things is a cap, and the long dark thing is a
resistor, but the other the long yellow thing is another cap... if you can
read the part number on the rectifiers you can probably google up their
rating but they look kinda wimpy to me.

I'd say there isn't much for you to use here.

Please take this the right way, I don't mean to flame you, but if you don't
know parts like this by sight I'd be worried about you trying to build
anything as highpower as a welder...

Dave August


"dave" wrote in message
news:8hMOd.106427$Jk5.58877@lakeread01...
I've dismantled what looks to me like a huge (probably 1987 vintage)
standby UPS (uninteruptable power supply). looks like it contains a nice
big rectifier bridge (with four diodes and 2 'unknown' black things on
it). also on the same unit are two small mini-circuit boards, which serve
'function unknown'. anybody with ANY clues whatsoEVER welcome to respond
:-) becasue I'm in a 'zero visibilty fogbank' here....

here it IS:

http://members.cox.net/dave_c/bridge_rectifier_etc/

also found within same unit a huge transformer, which might become (after
being partially unwound then part REwound) the core transformer of a
'homebrewed' welding high frequency converter ('later' :-). comments
appreciated as to wether or not some/any, or none of these parts could be
suitable for purposes intended (mainly the AC to AC/DC miller
thunderbolt220 volt buzzbox conversion purpose), and, if that's 'totally
unknown without their specs', what test procedures I could follow to
determine wether or not these parts are
a. in fact still 'good', and/or
b. how their specific capacities,'specs', or ratings can be determined?
(when not found on net)

please no "just buy a new or used one" replies after circuit design etc
I intend to house the AC/DC "adapter" in a seperate (probably old
computer) case.

I'm not even sure IF (one of the components pictured) *IS* a bridge
rectifier, jus' for starters :-/

thanks for educating me

box

ps-some of the threads below gave me this hairbrained idea ;-).

http://groups-beta.google.com/group/...2a632e04b91bad
thread: change your AC welder to AC/DC- *how*

http://www.tigdepot.com/products/p35TD-BBTF.htm
Mr Tig-conversion ideas for buzzbox to AC/DC/TIG box....

http://groups-beta.google.com/group/...dc5125b81d34d7
another thread on AC/DC diodes/chokes and bridges

http://groups-beta.google.com/group/...15305e672 66e
using SCR to change AC to AC/DC welders...maybe

http://groups-beta.google.com/group/...8c25a7372 c9b
or maybe use 150 amp diodes in the bridge

http://groups.yahoo.com/group/Weldin...s/message/2927
guy built a BULLETPROOOF bridge rectifier....

and some of the "high frequency unit - build it yourself idea" threads:

http://groups-beta.google.com/group/...1e726748458399
thread re hi frequency DIY

http://www.geocities.com/CapeCanaver...tarter/hf.html
Welding Arc Stabilizer-homemade DIY high-frequency
ADAPTER++++++++++++++++++++++++++

http://www.hotrodders.com/t43272.html
TIG "arc starters"-thread

http://www.electronics-list.com/Top_...struction.html
tersla coil-Construction, Best Links (tesla coil primary circuits and
"high frequency adapter welder" boxes are VERY similar, components-wise,
according to some threads)

http://www.electrophile.8m.com/bargsors.htm
The Basement-obtaining tesla parts VERY CHEAPLY-how