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Carryover of power in the plating tank with power off

We are having some arcing problems in our tanks. Our operators turn power off to the rectifier and there is still power in the plating bar or stripping bar. We have been discharging the power with a cable to the cathode bar. I was wondering if there was something out there that would take care of this problem so when the operator turned power off on the plating or strip tank there would be no carryover of power in the plating or stripping bar.

ERIC SUNSTROM
PLATING - ATLANTA, Georgia
March 3, 2010

Hi, Eric. I've never heard of such a thing! Sounds to me like the power is coming via leakage from another rectifier, not a capacitance effect.

Regards,

Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
March 3, 2010

March 4, 2010

Eric

We have/had a similar problem not too long ago with an older Rapid water cooled rectifier; 24v / 3000amp. With the rectifier powered on but with both pots at zero, the first rack would arc at the buss bar when the rack was submersed into the solution. Subsequent racks of the same load would not. Meters would show no current or voltage, but a definite arc. SCR's & diodes checked fine, and we replaced about $1000's worth of boards to no avail. It was pulled from service and a back-up was installed. We did not do any further work on the unit.

Anyone have any fixes?

Willie Alexander
- Colorado Springs, Colorado

Maybe there were "Choke Capacitors" installed on the rectifiers to reduce ripple. That could explain it.

LK

Lyle Kirman
consultant - Cleveland Heights, Ohio
March 8, 2010

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