[ARC5] Use of a Variac

[Mike Feher]

I do not want to continue this thread beyond its usefulness, and it probably
reached that. However, I think that anyone who is used to reforming caps
knows to current limit and start at a low voltage and slowly apply
increasing voltage while keeping the current low as it reforms. 73 - Mike 

 

Mike B. Feher, N4FS

89 Arnold Blvd.

Howell NJ 07731

848-245-9115

 

-----Original Message-----
From: arc5-bounces at mailman.qth.net <arc5-bounces at mailman.qth.net> On Behalf
Of Scott Robinson
Sent: Thursday, April 23, 2020 5:48 PM
To: Tom Lee <tomlee at ee.stanford.edu>; arc5 at mailman.qth.net
Subject: Re: [ARC5] Use of a Variac

 

Folks,

 

Most electrolytics will re-form by applying voltage across them. Problem is
that if the rated voltage has deteriorated from, say 450V to 200V, and you
apply 350V suddenly, the forming current can be quite large and generate
destructive amounts of heat. The reason for current limiting or Variac use
is to limit the forming current and consequent heat by spreading the forming
process over time.

 

Peace and health,

 

Scott Robinson

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