[Amps] Variac repairs

[K8LEEWMM at aol.com]

Steve
easy to fix!  take it apart,,, maybe take some pictures first, remove  1 
full winding,where it has burnt, and resolder. I used silver. regular solder  
will work. But every time that i have "smoke" from a variac it was due to a 
very  large overload for a long time.
so yes take it apart clean scrap the wire ends, try not then to turn all  
the way to the repaired end.
 
                                       73
                            wayne k8lee
 
 
In a message dated 12/26/2009 4:38:22 P.M. Eastern Standard Time,  
K1SG at aol.com writes:

In  pre-testing a junkbox Variac before using it for filament control, I   
watched it arc and spark and burn out the winding near the high  voltage  
end.  
Does anyone do Variac repair and rewinding? Or is  that another "lost  art?"
As a side question, I was running the variac  into a step-up transformer,  
which was unloaded. Does the primary of  an unloaded transformer present a  
significant load? Some Specifics:  5A Variac driving a 120:240VAC 
transformer 
of  unknown power  capability, weighing probably about 10 pounds. I know if 
I 
put a  2.5  A load on the 240V side, I'm drawing 5A through the primary, so 
I'm  staying  well below that level. The question is, do winding 
resistance,  
core losses, etc,  add a large enough load to fry the Variac in front  of 
the 
transformer?
Thanks,

Steve

Steve   Gilbert
K1SG
K1SG at AOL.com
508-435-9133
FN42fe
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