From: Bob Blick <bobblick@outlook.com>
To: Microcontroller discussion list - Public. <piclist@mit.edu>
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Date: Wed, 9 Sep 2020 22:32:01 -0700
Subject: Re: [EE] Microwave Oven Transformers
Thread-Topic: [EE] Microwave Oven Transformers
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Hi Ryan,
I needed an inductor good for over 100 amps.

One of my welders is a tiny thing as small as a lunch box. It's very conven=
ient and efficient but doesn't like cellulosic electrodes, I want to see if=
 adding inductance in series improves things. More likely, it will kill my =
welder after it kills the MOVs I add as protection :)

There's very little real information available about why inverter-based wel=
ders usually don't work well with cellulosic electrodes. A lot of talk abou=
t open-circuit voltage not being high enough. That's clearly wrong, since t=
he open-circuit voltage only affects the starting of the arc, and the probl=
em here is the arc dying out. Cellulosic electrodes produce a lot of hydrog=
en, which does raise the arc voltage slightly, but it should be well within=
 the welder's capability. I've run the welder on both 120 and 240 volts to =
see if that changes things, and it doesn't, which it would if the arc volta=
ge was the problem. I think the real problem is the current limiting in the=
 welder getting confused by the aggressive percussive arc that cellulosic r=
ods produce.

There is a whitepaper by ESAB(a welding equipment manufacturer) about the t=
opic, and they suggest that inverter-based welders need large inductors in =
order to use cellulosic electrodes. So that fits in with my hypothesis.

Even if it works out, the inductor probably won't become part of the welder=
, since it weighs as much as the whole welder. Just a little work avoidance=
 exercise here in my little corner of the hobby-sphere.

Friendly regards, Bob

________________________________________
From: piclist-bounces@mit.edu <piclist-bounces@mit.edu> on behalf of Ryan O=
'Connor
Sent: Wednesday, September 9, 2020 9:42 PM
To: Microcontroller discussion list - Public.
Subject: Re: [EE] Microwave Oven Transformers

That's not many turns. What are you going to use it for?

--=20
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