[BC] Transmitter Safety

[Xmitters at aol.com]

 >  Date: Mon, 28 Apr 2008 12:01:48 -0700
 >  From: "John Lyles"
 >
 >  At work (particle factory) we have written policies now, that require
 >  a second person when even just opening up a HV power supply for
 >  maintenance. Once the caps have been gone over with a shorting stick,
 >  and the incoming AC lines are not only locked out, tagged, but
 >  verified to be zero voltage, the second person doesn't have to be
 >  present. But if testing is needed, with doors open, then we have not
 >  only to produce a second person, but to have a special written policy
 >  for that one particular job.

Hi John:

This sounds familiar. When I was visiting fermilab, they had one of the
Continental Electronics 5 megawatt power amps down for repair. The 
scene looked
very similar to what you describe. I think there were about three 
people working
on it. They were doing some high voltage troubleshooting on one of the lower
voltage sections (the 6 kV for the modulator-driver as I remember), which was
tripping an overload relay.

One thing that I've never figured out, and someone on this list may be able
to shed some specifics on this, but what is the second person 
expected to do if
I get across 9500 volts that stops my heart?  Hopefully turn off the 9500
volts, but what about turning my heart back on?? Now if the rescue squad were
close enough to jump-start my heart within five minutes of the incident, then
this would make sense. I have never seen any mention of CPR training, 
and I don't
understand why that is. What exactly is that person supposed to do that is
universally effective at lifesaving without CPR training? Lockout/tag-out when
I'm the only person on site?  Can you say "busy work?" Sure, I knew you could!
Go through the motions, and to hell with whether or not the effort is
effective or not. The US government, at your disservice.

OH, I know! you get the coaching from the 911 operator over my cell phone, as
every third word gets dropped, thanks to the high performance digital
cellular phone. That of course, assumes the call does not drop after 
the operator
tells me to tilt the victim's head back, look for and clear any obstructions,
then you ...... Dead silence (no pun intended).

Now if I were the second person witnessing someone getting slammed by
heart-stopping high voltage, I would probably head for a lifetime 
worth of deep
depression if that person died because I was not effective or trained 
in some way
in saving the person's life. In that case, I would rather be the person zapped
rather than the bystander. I would rather be dead.

The absolute worst shock I ever got was about 550 volts from my Drake T-4XC.
It was a hot summer day and I was sweating like crazy, adjusting the PA
neutralizing cap with a jeweler's screwdriver!  Yea, I know, it is 
supposed to be
nonmetallic. The tip kept breaking off of my nonmetal twiddle sticks. And yea,
the plate voltage is normally off for a neut adjustment. That was 25 years ago
so I don't remember the details; only that it HURT!

First runner up was the 110 VDC fixed bias supply on my FM-20H3. I forgot
about tripping that low-voltage breaker on the wall before opening up the
transmitter. The tip of the 20H3 Jesus stick has a chunk burned out 
of it when the
center phase of the Main fused disconnect failed to open!  Ya gotta discharge
everything ya know, and apparently someone did! That situation was a 
death trap
waiting for carelessness.


Jeff Glass, BSEE CSRE
WB9ETG since 1970
DEC 6180 Win NT 4.0 SP6A AOL 5.0