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Re: how do you mount a variac?



Original poster: "Terry Fritz" <teslalist-at-qwest-dot-net>

Hi Adam,

Variacs at 1kVA and above should have like three/four big hefty bolt holes 
to mount to a front panel.  Note my control box at:

http://hot-streamer-dot-com/temp/NSTva_html_mfa757e7.jpg

has four bolts around the big black knob for mounting.  Here is a big raw 
wild variac found sill on the hoof:

http://hot-streamer-dot-com/temp/P1150050.jpg

Note the three bolts on the face (one removed) that even have rubber 
washers on them.


If a 10 meg ohm resistor has 1000 volts RMS across it (worst case), we are 
talking less than 1/10th watt.  So, say 50 resistors are 5 watts.  Might as 
well be zero...  The bleed resistors are a trivially small percent of a 
coil's power loss.  that loss is constant as long as the power is on.  They 
just drain the thing down once the power is removed.  Without bleeder 
resistors, the voltage stays high for weeks!!!  Five seconds of drain time 
is not a factor when the cap charges at 1/120th of a second normally.

Cheers,

         Terry



At 08:48 PM 1/15/2003 -0500, you wrote:
>I am in the process of building my control box for my coil and I can't 
>figure out how to mount the coil on to my box. I have seen people's 
>variacs that are just hanging there, but their are no bolts on the other 
>side... Also, on a slightly random note, when you turn off the power to 
>your caps, how much heat do the bleeder resistors give off?
>Thanks
>Adam