[R-390] Snubber leakage

[Charles Steinmetz]

Perry wrote:

>Jim wrote: Unless my calculations are wrong, the impedance of 0.1uF 
>at 60 Hz is about 26K ohms, so the current leakage is less than 5ma.
>
>Yea verily thy calculations are accurate. But we have high voltage 
>on the secondary.
>
>Then the problem arises if ones fingers touch the wrong terminal.

First Rule of Technicians Who Want to Stay Alive:  Don't poke around 
inside equipment while it is still plugged in.  Only a fool relies on 
the power switch.

>For me the inrush thermistor is my choice.

The vast majority of arcing occurs when the power switch is turned 
OFF and interrupts the inductive (transformer) load.  Not, of course, 
the arc that actually welds the switch closed -- but that arc is able 
to do so only because of the damage previously done to the switch 
contacts by the OFF cycles.  An inrush device does nothing whatsoever 
to mitigate arcing when the switch is turned OFF.  On the other hand, 
that is what snubbers are all about.

Snubbers across power switches have a long history.  There are 
probably billions installed in all sorts of consumer and industrial 
equipment, including tube equipment with high-voltage transformer secondaries.

Chris suggested using a safety capacitor.  Excellent idea.

Best regards,

Charles