Last week Ernie Leimkuhler held a mig welding tutorial at Grant's
place ( Thanks again Grant and ernie!). Ernie told me that the high
voltage caps in the high frequency circuit go bad and it is hard to
find replacements for them. I had noticed that something was dripping
on the floor underneath the Miller Goldstar welder. I searched in
without success for the source of the drips. Then yesterday I found
the source while wiring in an extra relay and receptacle. The relay
connects the receptacle to 115 volts which then powers up the water
cooler for tig welding. The source is the high voltage capacitors.
some kind of oily substance is coming out of them and dripping down
the red phenolic mounting board. Ernie was right, these caps are hard
to find. In fact, using google tonight to find these caps was
fruitless. They are mica capacitors. Can types other than mica be
used? And can they be paralleled to increase the value? Is there a
better type than mica? And finally, does anybody here have some to
sell?
Thanks,
Eric R Snow

"Eric R Snow" tesnow@whidbeyDOTcom wrote in message
...
Last week Ernie Leimkuhler held a mig welding tutorial at Grant's
place ( Thanks again Grant and ernie!). Ernie told me that the high
voltage caps in the high frequency circuit go bad and it is hard to
find replacements for them. I had noticed that something was dripping
on the floor underneath the Miller Goldstar welder. I searched in
without success for the source of the drips. Then yesterday I found
the source while wiring in an extra relay and receptacle. The relay
connects the receptacle to 115 volts which then powers up the water
cooler for tig welding. The source is the high voltage capacitors.
some kind of oily substance is coming out of them and dripping down
the red phenolic mounting board. Ernie was right, these caps are hard
to find. In fact, using google tonight to find these caps was
fruitless. They are mica capacitors. Can types other than mica be
used? And can they be paralleled to increase the value? Is there a
better type than mica? And finally, does anybody here have some to
sell?
Thanks,
Eric R Snow

I would expect Miller to have the parts available, at least unless the
welder is an antique. It's a big part of why I bought a Miller instead of
an off-shore el-cheapo. That being said, in order to find a suitable
replacement from other sources, you need to know the characteristics of the
capacitor you are trying to replace. And it is more than just the
capacitance and voltage. Many types of capacitors don't take kindly to
being charged backward and, if you put AC across them, they'll literally
explode. Even if they have enough of a DC charge on them that they never
see a reverse polarity, if they have a significant effective series
resistance (ESR), they'll get hot and blow if there is a substantial AC
signal riding on the DC. And this just scratches the surface...

Jerry

Eric R Snow tesnow@whidbeydotcom wrote:
Last week Ernie Leimkuhler held a mig welding tutorial at Grant's
place ( Thanks again Grant and ernie!). Ernie told me that the high
voltage caps in the high frequency circuit go bad and it is hard to
find replacements for them. I had noticed that something was dripping
on the floor underneath the Miller Goldstar welder. I searched in
without success for the source of the drips. Then yesterday I found
the source while wiring in an extra relay and receptacle. The relay
connects the receptacle to 115 volts which then powers up the water
cooler for tig welding. The source is the high voltage capacitors.
some kind of oily substance is coming out of them and dripping down
the red phenolic mounting board. Ernie was right, these caps are hard
to find. In fact, using google tonight to find these caps was
fruitless. They are mica capacitors. Can types other than mica be
used? And can they be paralleled to increase the value? Is there a
better type than mica? And finally, does anybody here have some to
sell?
Thanks,
Eric R Snow

post pics of the caps and any markings on them.

On Sun, 16 Oct 2005 03:36:40 GMT, tesnow@whidbeyDOTcom (Eric R Snow)
wrote:

Last week Ernie Leimkuhler held a mig welding tutorial at Grant's
place ( Thanks again Grant and ernie!). Ernie told me that the high
voltage caps in the high frequency circuit go bad and it is hard to
find replacements for them. I had noticed that something was dripping
on the floor underneath the Miller Goldstar welder. I searched in
without success for the source of the drips. Then yesterday I found
the source while wiring in an extra relay and receptacle. The relay
connects the receptacle to 115 volts which then powers up the water
cooler for tig welding. The source is the high voltage capacitors.
some kind of oily substance is coming out of them and dripping down
the red phenolic mounting board. Ernie was right, these caps are hard
to find. In fact, using google tonight to find these caps was
fruitless. They are mica capacitors. Can types other than mica be
used? And can they be paralleled to increase the value? Is there a
better type than mica? And finally, does anybody here have some to
sell?
Thanks,
Eric R Snow

You'll need to know working voltage and capacitance. Then google on
"transmitting mica". High voltage mica caps are routinely used in
radio transmitters. Yes, they can be paralleled to get the required
capacitance. If size, performance and cost are the measures of
"better", I doubt if there's a better cap for this app than mica.

high voltage mica caps aren't hard to find, I have a 30,000 VAC mica cap
sitting here at this moment - it's about 8 inches X 6 inches X 12 inches,
with a 8 inch insulator on top, the case is one terminal, the other is on
top of the insulator.

I suspect your TIG welder needs a lower voltage.

Mica has particular dielectric benefits in certain frequency bands - and oil
dripping out is not a real problem, jsut remove the cap, refill with oil and
seal it again. use mineral oil if you can't find capacitor oil.


" They are mica capacitors. Can types other than mica be
used? And can they be paralleled to increase the value? Is there a
better type than mica? And finally, does anybody here have some to
sell?
Thanks,
Eric R Snow

"william_b_noble" wrote in message
news:1129443990.371761fa123e7cca0b6df5fa678f46c1@t eranews...
high voltage mica caps aren't hard to find, I have a 30,000 VAC mica cap
sitting here at this moment - it's about 8 inches X 6 inches X 12 inches,
with a 8 inch insulator on top, the case is one terminal, the other is on
top of the insulator.

I suspect your TIG welder needs a lower voltage.

Mica has particular dielectric benefits in certain frequency bands - and
oil dripping out is not a real problem, jsut remove the cap, refill with
oil and seal it again. use mineral oil if you can't find capacitor oil.

Just make sure it's oil in there, not PCB. What vintage is the machine?

regards,

John

On Sun, 16 Oct 2005 19:11:32 +1000, "john johnson"
wrote:


"william_b_noble" wrote in message
news:1129443990.371761fa123e7cca0b6df5fa678f46c1@ teranews...
high voltage mica caps aren't hard to find, I have a 30,000 VAC mica cap
sitting here at this moment - it's about 8 inches X 6 inches X 12 inches,
with a 8 inch insulator on top, the case is one terminal, the other is on
top of the insulator.

I suspect your TIG welder needs a lower voltage.

Mica has particular dielectric benefits in certain frequency bands - and
oil dripping out is not a real problem, jsut remove the cap, refill with
oil and seal it again. use mineral oil if you can't find capacitor oil.

Just make sure it's oil in there, not PCB. What vintage is the machine?

regards,

John

The machine was built in the early seventies. Were PCBs used then? I
think they were. If they are leaking PCBs then wouldn't the best fix
be just re-filling with non PCB oil and sealing them? I could take
them to the county as hazmat but then they would have to deal with
them.
ERS

Eric R Snow wrote:

On Sun, 16 Oct 2005 19:11:32 +1000, "john johnson"
wrote:


"william_b_noble" wrote in message
news:1129443990.371761fa123e7cca0b6df5fa678f46c1@ teranews...
high voltage mica caps aren't hard to find, I have a 30,000 VAC mica cap
sitting here at this moment - it's about 8 inches X 6 inches X 12 inches,
with a 8 inch insulator on top, the case is one terminal, the other is on
top of the insulator.

I suspect your TIG welder needs a lower voltage.

Mica has particular dielectric benefits in certain frequency bands - and
oil dripping out is not a real problem, jsut remove the cap, refill with
oil and seal it again. use mineral oil if you can't find capacitor oil.

Just make sure it's oil in there, not PCB. What vintage is the machine?

regards,

John

The machine was built in the early seventies. Were PCBs used then? I
think they were. If they are leaking PCBs then wouldn't the best fix
be just re-filling with non PCB oil and sealing them? I could take
them to the county as hazmat but then they would have to deal with
them.
ERS

It the cap does not have "no PCBs" printed on it than it can be assumed
to contain PCBs which means you've got a bit of a problem on your hands
if it leaked.

Pete C.

Pete C. wrote:
Eric R Snow wrote:

On Sun, 16 Oct 2005 19:11:32 +1000, "john johnson"
wrote:


"william_b_noble" wrote in message
news:1129443990.371761fa123e7cca0b6df5fa678f46c1@ teranews...
high voltage mica caps aren't hard to find, I have a 30,000 VAC mica cap
sitting here at this moment - it's about 8 inches X 6 inches X 12 inches,
with a 8 inch insulator on top, the case is one terminal, the other is on
top of the insulator.

I suspect your TIG welder needs a lower voltage.

Mica has particular dielectric benefits in certain frequency bands - and
oil dripping out is not a real problem, jsut remove the cap, refill with
oil and seal it again. use mineral oil if you can't find capacitor oil.

Just make sure it's oil in there, not PCB. What vintage is the machine?

regards,

John

The machine was built in the early seventies. Were PCBs used then? I
think they were. If they are leaking PCBs then wouldn't the best fix
be just re-filling with non PCB oil and sealing them? I could take
them to the county as hazmat but then they would have to deal with
them.
ERS

It the cap does not have "no PCBs" printed on it than it can be assumed
to contain PCBs which means you've got a bit of a problem on your hands
if it leaked.

You could also assume it's full of gold, but that's wrong too.

Eric R Snow wrote:

On Sun, 16 Oct 2005 19:11:32 +1000, "john johnson"
wrote:


"william_b_noble" wrote in message
news:1129443990.371761fa123e7cca0b6df5fa678f46c1@ teranews...
high voltage mica caps aren't hard to find, I have a 30,000 VAC mica cap
sitting here at this moment - it's about 8 inches X 6 inches X 12 inches,
with a 8 inch insulator on top, the case is one terminal, the other is on
top of the insulator.

I suspect your TIG welder needs a lower voltage.

Mica has particular dielectric benefits in certain frequency bands - and
oil dripping out is not a real problem, jsut remove the cap, refill with
oil and seal it again. use mineral oil if you can't find capacitor oil.

Just make sure it's oil in there, not PCB. What vintage is the machine?

regards,

John

The machine was built in the early seventies. Were PCBs used then? I
think they were. If they are leaking PCBs then wouldn't the best fix
be just re-filling with non PCB oil and sealing them? I could take
them to the county as hazmat but then they would have to deal with
them.
ERS

The following might be of use:

http://www.epa.gov/opptintr/pcb/

Pete C.

john johnson wrote:

Just make sure it's oil in there, not PCB. What vintage is the machine?

regards,

John

Mmmmmmmmmmmm! IMO, nothing beats PCB's spread on a ritz cracker :-)

On Sat, 15 Oct 2005 23:26:26 -0700, "william_b_noble"
wrote:

high voltage mica caps aren't hard to find, I have a 30,000 VAC mica cap
sitting here at this moment - it's about 8 inches X 6 inches X 12 inches,
with a 8 inch insulator on top, the case is one terminal, the other is on
top of the insulator.

I suspect your TIG welder needs a lower voltage.

Mica has particular dielectric benefits in certain frequency bands - and oil
dripping out is not a real problem, jsut remove the cap, refill with oil and
seal it again. use mineral oil if you can't find capacitor oil.


Capacitor oil kinda sounds like skyhooks and file grease. I'm sure
it's not. I'll look for it and try to see why the things are leaking.
Will oil loss make the capacitance lower?
Eric
" They are mica capacitors. Can types other than mica be
used? And can they be paralleled to increase the value? Is there a
better type than mica? And finally, does anybody here have some to
sell?
Thanks,
Eric R Snow

Eric R Snow wrote:

On Sat, 15 Oct 2005 23:26:26 -0700, "william_b_noble"
wrote:

high voltage mica caps aren't hard to find, I have a 30,000 VAC mica cap
sitting here at this moment - it's about 8 inches X 6 inches X 12 inches,
with a 8 inch insulator on top, the case is one terminal, the other is on
top of the insulator.

I suspect your TIG welder needs a lower voltage.

Mica has particular dielectric benefits in certain frequency bands - and oil
dripping out is not a real problem, jsut remove the cap, refill with oil and
seal it again. use mineral oil if you can't find capacitor oil.


Capacitor oil kinda sounds like skyhooks and file grease. I'm sure
it's not. I'll look for it and try to see why the things are leaking.
Will oil loss make the capacitance lower?
Eric
" They are mica capacitors. Can types other than mica be
used? And can they be paralleled to increase the value? Is there a
better type than mica? And finally, does anybody here have some to
sell?
Thanks,
Eric R Snow



Here is a site with hv mica caps. I would use this one:
CFT) 224M356 .001 µF (dual) 10 kv 1-1/8" x 1-7/8" 9.00

IF it is a dual cap you can parallel it to get the .002 uf that you
need. The cap is rated at 10 kv which is just the voltage rating. A
higher rating will work the same.


http://www.surplussales.com/Capacito...misctrans.html



John

On Sun, 16 Oct 2005 03:36:40 GMT, tesnow@whidbeyDOTcom (Eric R Snow)
wrote:

Last week Ernie Leimkuhler held a mig welding tutorial at Grant's
place ( Thanks again Grant and ernie!). Ernie told me that the high
voltage caps in the high frequency circuit go bad and it is hard to
find replacements for them. I had noticed that something was dripping
on the floor underneath the Miller Goldstar welder. I searched in
without success for the source of the drips. Then yesterday I found
the source while wiring in an extra relay and receptacle. The relay
connects the receptacle to 115 volts which then powers up the water
cooler for tig welding. The source is the high voltage capacitors.
some kind of oily substance is coming out of them and dripping down
the red phenolic mounting board. Ernie was right, these caps are hard
to find. In fact, using google tonight to find these caps was
fruitless. They are mica capacitors. Can types other than mica be
used? And can they be paralleled to increase the value? Is there a
better type than mica? And finally, does anybody here have some to
sell?
Thanks,
Eric R Snow

Oh oh....Now Erics place is a Hazmat site. PCBs...Run Erick Run!!1


G


http://www.arcowelder.com/

Call and ask for Dennis. Tell him Gunner refered you. Id be surprised
if he didnt have some good used ones kicking around

Gunner

"Pax Americana is a philosophy. Hardly an empire.
Making sure other people play nice and dont kill each other (and us)
off in job lots is hardly empire building, particularly when you give
them self determination under "play nice" rules.

Think of it as having your older brother knock the **** out of you
for torturing the cat." Gunner