+1500 vdc on pvc wire and rubber grommet thru chassis - safe?

[N3DRB The Derb]

I'm a bit scared on running +1500 on a pvc coated wire thru rubber chassis grommet. no burn marks or zorches, so it has been working. Am I being paranoid? I would have used a ceramic feedthru and I still might.

[w3jn]

Should be FB OM unless the grommet has deteriorated.  Sometimes ceramic feedthrus are more trouble!

BTW that pack of NTC thermistors and 1N4007s apparently never reached you.  I got half the torn envelope back in the mail Sat (took 3 weeks to get back?).  Guess the sorting machine ate it.  I'll send off some more...

[KD3CN]

Johnny,
The post office wants you to but bulky stuff like that in a padded envelope, and mark it "hand cancel only".  I had the same thing happen recently with an envelope of parts I sent Uncle Willy.  Of course the post office is worried about the extra parts going thru their machines.   

Karl

[WBear2GCR]

Well, actually no!

If it goes through the air, then the air is doing the insulation and it might as well be bare wire. I'd not count on the grommet, since the leakage through the jacket of the PVC wire will be significant - and where it starts to think it is close to ground (like through the grommet) it will produce some ionization (ozone) which will degrade the grommet faster. In humid weather it will get worse.

I'd strip out the center conductor of some RG-58/59 and use that.
The insulation is better, thicker and more suited for the job.
Run that through the grommet.

Of course one could kludge it by using some heat shrink layers +/- 1/2" or more either side of the grommet for safety.

Or, run the wire through some Teflon spagetti or other spagetti to increase the margin...

Bottom line is that PVC insulation is generally rather leaky stuff.


         _-_-bear

[WQ9E]

I agree with Bear and teflon is probably the way to go if you can get some. I bought a 100 foot roll from Fair last year, much easier to work with than the HV wire that RF parts sells.  I dislike the RF Parts stuff because the insulation sticks to the fairly fragile conductor which makes it difficult to remove the insulation without damaging the conductor.  The only more annoying wire I have dealt with is some direct burial coax that has the sealing goop inside; that stuff is a major pain to keep clean long enough to tin the braid. 

Rodger WQ9E

[N3DRB The Derb]

I'm going to grab some red teflon silver wire and rewire with that. This thing has a laced wiring harness - actually 2 of them - one factory with black lace and one done later with white lace. The 1500 vdc is neatly wired in next to all the other PVC wiring in the white laced one. I checked the grommets and they are all good and rubbery. Gonna switch to teflon anyways. I also exiled the 40+ year old Federal RG-8U output coax. Got a lot of RG400 and silver connectors coming soon for interconnects patches and whatnot. ebay is great for deals on such crap. Often times you can get lots of 3 to 6 ft  rg-142 or rg-400 coax with good silver connectors on them for 2 to 4 bucks each.

John, no, I never got the care package. The nasty wx coming our way is going to prevent any more outside work for a day or 2.  I wanted to solder patch and feed the 450 ladder line in thru the PVC to get back on barefoot. Supposed to get 3+ inches up here. I did get all the ground rods silver soldered and interconnected with 3 strands #6 copper, hooked up with a huge soldered compression nut going into the shack. This will feed into a copper bulkhead .250" thick inside the shack where ground will go to a branched 1/2" copper pipe and then to rigs tuners etc. All the coax will feed thru this copper bulkhead. I have another issue which I'll start another thread on.

I think I'll take a few progress pictures soon. I plan on writing a article on the functional resto job once completed and proven with a few weeks of air time under battle conditions.

I am going to get a boatload of parts and crap in the next few days. Holidays delayed everything.

[w3jn]

crap.  Well I'll gin up another package.  Anything else you need?  Ceramic feedthrus?  Gimme your shopping list and chances are I have it.

[N3DRB The Derb]

I think with the stuff I got coming I'll be good to go. Send me about 30 of those diodes. Oh wait, have you got 20 100K 2 watt resistors? I could use them asap - I took out the old cap bank last night and now I'm figuring out how best to build up the new filter string, and do I want it above chassis but protected with clear lucite/plexy or below and 5 big empty holes in the chassis? I'm thinking above with a clear blast shield above the lytics + keeping yer mitts offa the HV. look at the former filter mounting plate. One of those caps was a 470 K resistor. The others were ok as far as leaks or shorts, but they just dont have a lot of energy storage left.

BTW, the factory bulletin about the PIV issue mentions using 'controlled avalanche' diodes, and clipping out the 47K resistors in parallel when you do the mod. I may be a young buck but I have never heard of a controlled avalanche diode. WTF is that? It gives no part number. Maybe I would be better off just grabbing one of those big ass bridge rectifier blocks the amp builders use.

here's some pics showing current state of affairs. many parts going in soon as they arrive. Yeah I could use a small size feed through for the b+. Dont care much for the pvc wire and grommet setup, not with 1500 volts at 1000ma. Pix enclosed.

P.S. I look gay as hell.  Always gotta go for the gag.

 



 

[The Slab Bacon]

If you can either get me the dimensions of or mail me the original cap mounting card, I will make you a new one out of 1/4" lexan and send it back to you. This will put the new caps in the same mounting spotz as the originals. I will pre drill the holze so it is a drop in replacement.

As far as the plate supply wiring goes, that stuff should be fine. Dont forger that on a leanyour the voltage falls on mod peaks instead of swinging to double as on a plate mod rig. If ur uncomfortable with it, just slip some spaghetti tubing over it for good luck.
                                    the Slab Bacon
                           

[N3DRB The Derb]

I forgot about that. I was thinking exactly that about plate mod. I got the antenna hooked back up, the feedline soldered, and I'm connecting up the Yeasu and the tuna. Should be on in a little while barefeets. Hope the band is not crapped out. I'll take some pix of the cap board and measure twice.

[N3DRB The Derb]

oh forgot to add I'm not using the old caps. I'm using new axial lead rubycons with a 105 degree C rating.  I could pull the guts out of the old caps after having fun with a cut off wheel, but I rather like showing off my mad point to point wiring skillz. 

btw 75 is crap right now. ( 8pm est Wed. )  I got the Yaesu hooked back up. band is just crap. 

[w3jn]

DRB, no 100K/2whats to be found in the store room.  Gots plenty of 220K/2W or 470K/2W.  These are being used as equalizing resistors across the filter caps, no?  If so I think the 220Ks would be FB.

Lemme know and I'll shoot 'em out with the diodes and the inrush current limiter.

[WD8BIL]

Yup.... the 220Ks will work OKFB John.

Timmy: If ya can, check into the "What's for Dinna Net" sometime. 3733Khz at 5 P.M.
I think the Yahoo 101 barefoot would do FB at that time. Hell, 54 watt Fred does real gooder here in Ohio.

I'd LOVE to hear the Derb in my SP100's speaker !!

[WA2AAE]

You might try get some test probe wire. If it is good quality wire it should handle the 1500V.

73, Harv

[WBear2GCR]

The "teflon" (tm DuPont) wire is better than that PVC.

But iirc, type "EE" is rated at 600volts.

Best to still add a sleeve over it where it comes near ground of any sort.
worst case you can strip off the insulation of some #14 or #12 house wire and use that! I use silicone spray to make things slide through things like that better.

1500vdc is in another league compared to 1000vdc and below...  imho.

            _-_-bear

[N3DRB The Derb]

Bud,

I wuz on awhile ago, talked a few minutes with tom 3KLR. he said I wuz swinging it. Some one was lookin at me with a scope and said I had huge positive peaks quote/unquote. Cant remember who. AM filters are now running 115 bucks brand new. I'm gonna get me some.

John,

sure thang throw them in there. They will do the trick.  I am getting a bite offa the D-104 - not a bad one, but you can feel it if you touch it. I also got some relay troubles. I dropped the maw down and got zero plate current a few times, then rekeyed and got it back. Something needs cleaned. Need to give that thing a big bath with some kleener. 

I'm changing things around a bit. The bench against the outside wall ( where the gear is now ) is going to become a 100% operating bench and the other bench is going to become strictly repair and rework. Now that I have the ground system in I gotta distribute it to the benches and from there to the rigs and future rigs & test gear. Gonna have a 100% silver soldered system from rods to rigs. No MOV's in here. The more reading I do the more I think they suck.

[N3DRB The Derb]

oh, regarding the wire, I must be stupid or something. Packard spark plug wire will take whatever a car spark coil will put out. Just have to make sure I get real copper wire, none of that suppression resistance BS. I want all the spark, all the time.

[N3DRB The Derb]

Bud,

I'll check in today at 5. 

[N0WEK]

The nearest neon shop will have HV wire that handles 15,000 vac in everyday use, which in sign transformers is 7,500 vac above ground. It's not even expensive.

[N3DRB The Derb]

or maybe not. the rig is giving me problems. Looks like a relay. I thinkin I'm going to have to take it offline and look at it. I'll key the rig and get no plate  current, unkey, rekey, and get output. Seems to only happen on key down or keyup.

[w3jn]

OK DRB I'll make up a care package and get it out to you, padded envelope this time 

[N3DRB The Derb]

roger on that OM.  Got some stuff today, haven't opened the boxes yet. Just got back.

I wanna show everyone a deal on something that might be useful to them. I could not believe it. you get 2 for 5 bucks. I'll start a new thread about it. if you got the parts from home depot to make it, it would be 6X that. I got 2, I should have got more. 

[ka3zlr]

Derb,

 Hey, I mean't to ask you, do you Need a yc-601 display for your 101 or did you get one with yours.. I think i have one here might be a little scratched up but I'm not using it...

[N3DRB The Derb]

No I don't have one, but teh analog dial don't bother me none. I was raised on them. 

if it's something you'll never use again or just dont have any use for, I'll put it to use and enjoy. what the hell. 

[Rick K5IAR]

Derb..

If you need neon sign wire let me know, I have a little surplus you're welcome to.

Rick/K5IAR