> > Date: Wed, 13 Jan 2010 03:55:50 EST
> From: texasrf@aol.com
> Subject: Re: [Amps] which HV connector to use?
>
>
> You are most fortunate Hardy. In addition to having the Millen connectors
> breakdown and turn into a resistor over time (at 4kv/8877), I was very
> nearly turned into an SK when the B+ wire broke off of one of them just
> as my
> left hand brushed the wire. I was out of commission for about ten weeks
> and
> have some nasty scars on that hand to commemorate the occasion.
>
> The wire that broke was some fancy neoprene covered hv cable. The
> insulation was wonderful but the center conductor was almost as robust as
> cheese. A
> few wiggles after soldering and the conductor would simply snap off the
> connector.
### I had an identical experience in 1977. The local electronic emporium
had 40 kv rated HV wire
available. It consisted of real fine stranded 18 ga wire.. and rigid Teflon
jacket. The Teflon jacket
was covered with red plastic.. so it all looked very nice. It was not very
flexible though, you had to
do a gradual 90 deg bend, etc.
## One day the end simply snapped right off the Millen male plug.. and
flopped about.. with a few strands
sticking out the end ! It was soldered correctly too. The soldering is
not the problem, the problem is/was
there is no strain relief where the HV cable enters the male Millen plug.
You can't put heat shrink over the
Millen male end.. and hv cable either. The Millen has to be able to
swivel/rotate. Broke off at the RF deck end,
and laid on the carpet, behind the desk, with a myriad of other cables.
## after that, I started using the super flexible 10 kv rated Red belden
test prod wire [ aprx .22"].
It's like spaghetti... and think it hi-pot tests to 20-25 kv. 18 ga
stranded, tinned conductor. I don't trust it either.
No strain relief on the Millen.....plus the HV wire insulation clearly
does not go in far enough on the back end
of any male Millen. As is, it barely goes in, b4 it butts up against the
solder hole. The red belden is just silicone rubber,
and if not careful, can easily be cut, nicked, and crushed. You could
easily slice the silicon rubber insulation with a razor/
sharp sheet metal, right to the conductor, and not even know it had a cut in
it. There goes your insulation. If a dog/cat can
chew through it, it's not tough enough.
>
> If the EPA ever gets wind of the potential for danger, the Millen hv
> connectors will become extinct and in my opinion deserved.
## EPA or worker's compensation board, etc. What really freaks me out, is
when I got my bare arm very close to the red belden
wire one day.. with +6950 vdc on... and all the hairs on my forearm, stood
up on end !! Think the Millen isn't screwed down tight?
Don't even go near one, with the B+ turned on. I'm surprised there hasn't
been lawsuits....yet.
>
> I can't see a banana plug arrangement being any safer unless there is some
> type of locking device to prevent accidentally unplugging the cable. I
> have
> seen some twist on connectors in the Mouser catalog that are interesting
> a
> maybe up to the job. The SHV connectors are certainly up to the task as
> well.
## I don't believe the Alden 15 kv matched pairs sold by SSON lock
together. The ones I saw had the 15" HV cable molded into each 1/2.
Then you are instructed to...."splice" onto both ends.. to lengthen.
That's two splices required. If you pulled on the cable, it would pull the
male end
right out of the mating chassis female.
## OK... what exactly do broadcast stations use for B+ connector's [and
HV cable] ??? I mean something in the 7-10 kv range.
## Like Gerald sez... you get whacked with B+.... you never forget it. I
just about killed myself in 1979, when [like an idiot] tightened down the
fan on my hb 3-500Z amp, with an excellite nut driver. My left bare forearm
was resting on the AL cab box.... while right hand tightening down the
nuts on the 120mm fan ...[inside of RF deck, with HV shut off]. The shaft
of the nut driver scraped the eimac anode connector of the single 3-500Z.
The anode connector was in the way really, so I slid my right hand down onto
the shaft of the nut driver, for a better grip ! All I remember was
waking up 10 mins later
9' across the room, dripping in sweat. I had used a mess of really small
oil caps, like the 2/4/6 uf variety, in series, and also plane parallel...
and NO bleeder at all.
The procedure to bleed em off was... shut off the B+.. then hit the PTT /
footswitch.... and the normal ZSAC of the tube alone, would bleed em off in
a split second .
I had no B+ voltmeter on either the rf deck... nor the external HV supply,
under desk #2. The kicker was... the HV supply had been shut off for
a full 5 x days
since I was working out of town at the time. I dunno to this day how
much B+ was on those oil caps... but they obviously held some charge after
5 x days.
later........ Jim VE7RF
>
> 73,
> Gerald K5GW
>
>
>
> In a message dated 1/13/2010 12:12:43 A.M. Central Standard Time,
> n7rt@cox.net writes:
>
> Hi All
> I have used those Millen connectors for years and never had a problem. Up
> to
> 4600 VDC.
> I am surprised at the complaints.....
> 73 Hardy N7RT
>
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