[AMRadio] problems

[Phil (VA3UX)]

At 09:26 PM 1/14/2002 -0600, you wrote:
>What's to stop the HV from breaking down, and arcing to ground on those
>connectors?  Are they rated at 2 or 3kVDC?  how about the peak voltage, if
>you're imposing hi-level, plate modulation voltage on those terminals?

The Millen connectors are rated for 7 KV.  However they have been known to 
fail (arc to chassis) at voltages well less than 7 KV, when mounted 
directly to the chassis as they were originally designed to be mounted.  To 
prevent premature failure the recommended chassis mounting procedure is to 
make a rectangular hole in the chassis that is much larger than the 
connector (say 1.5" by 1.5", even as much as 2" square), mount the 
connector on a piece of 1/8" or 1/4" thick teflon or polyethylene or 
plexiglas sheet cut larger than the hole, and mount the plastic sheet with 
connector attached over the hole.  This provides extra clearance between 
the Millen connector and the chassis.

Another problem I see with the single conductor type Millen connector is 
the possibility of connecting the B+ while forgetting to connect the B- or 
return. A good solution to this is the HV connector/cable assemblies made 
by Alden Products in MA. You can  get a nice dual cable, two pin locking HV 
connector assembly  for a reasonable price.  AMP also make some nice HV 
connectors but they're pricy.

The Millen connectors are also available from RF Parts in CA.

Phil


>I probably wouldn't think twice about using one for B+... but I wouldn't 
>use one
>for ground.  Instead, I think I'd rather use bonding strap to run from 
>piece to
>piece, or from the frame of one chassis to the side of the cabinet, or better
>yet, run all the ground lines to one lug, then that lug is also connected to a
>good, solid earth ground, via 10ga copper wire, firmly attached to a 10'
>copper-clad ground rod, stuck in the ground up to 9'9" (just enough for the
>clamp assembly on top.
>
>One can NOT over-do on grounding a multi-thousand volt rig.:
>
>: ----- Original Message -----
>: From: <w5sum at glowbugs.com>
>
>: > I also need to find a few
>: > millen HV safety terminals.. they have a 20 piece minimum order
>: > so that blew my plan of getting some ordered out the window. I
>: > need
>: > a pair of black ones and a pair of red ones.. caps and chassis
>: > mount part.. got any in  your junk box?
>
>
>
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