Since I don't really understand this stuff I can't really say other than
it uses a high voltage transformer coupled with a spark gap system to
generate the high frequency. Here is a link to the schematic. I
believe the two capacitors in question called the oscillator capacitor
and the by-pass capacitor.
Doug Braun wrote:
> How does it get the high frequency without any electronics?
> --- On Tue, 7/21/09, Brad Kahler <firstname.lastname@example.org> wrote:
>> From: Brad Kahler <email@example.com>
>> Subject: [Shop-talk] high frequency welder capacitors
>> To: firstname.lastname@example.org
>> Date: Tuesday, July 21, 2009, 11:24 PM
>> I have an older Linde / Union Carbide
>> AC/DC Tig/Stick welder (weighs 800 lbs!). It is a
>> great welder that I'm extremely happy with. There are
>> very few components that could go wrong with this welder
>> since it has no electronics in it what so ever.
>> However there are a couple of capacitors that I have seen
>> fail on similar welders. The particular capacitors in
>> question are in the high frequency circuit and are .002 mfd
>> Mica 5000 volt capacitors. I've picked up the
>> following capacitors as potential replacements should the
>> original ones finally fail. Later units used 10,000
>> volt capacitors probably due to failures of the lower
>> voltage units.
>> The ones I have picked up are listed below:
>> Sangamo Mica .002 mfd 5000 volts 6.2 amps 1000 k.c.
>> Mica .002 mfd 6000 volts 6.2 amps 1000 k.c.
>> Mica .002 mfd 6000 volts 13 amps @ 3000 k.c. or 11 amps @
>> 1000 k.c or 7.5 amps at 300 k.c.
>> Mica .002 mfd 10,000 volts 14 amps @ 1000 k.c. or 8 amps @
>> 300 k.c.
>> The Sangamo and the Cornell-Dubilier look identical, brown
>> rectangles with terminals on top and the only difference
>> being one has a potted assembly and the other has a little
>> plate with 4 rivets on the bottom in stead of potting.
>> The Aerovox and the Sprague are transmitting capacitors and
>> are cylindrical with mounting ears on top and bottom.
>> I am assuming the wires are attached to the top and bottom
>> mounting holes.
>> What I'm wondering is whether the transmitting capacitors
>> can be used in place of the original capacitor without
>> either being destroyed or not functioning properly in the
>> high frequency circuit of the welder.
>> Any thoughts?!
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