electric fencer

It musta beed on fire from the arcing, Pete.

Sorry, that's a different manual for the same item.

Certainly not a Stovepipe, on a metalworking newsgroup. ;-)

Then they take the credit for it.

An old Sci-Fi book made fun of that when the first FTL engine was invented by a TV repairman. The 'Blink Drive', named after Billy Bob Blink. I wish I could remember the title. :)

That's part of the job. Our reward is to be invited to play with their expensive toys next time. jsw

Had to sue. It claimed it was 1/2" copper pipe. :)

Techs do what engineers can't even dream of.

Only when they play by the rules. I've come into work to find my bench stripped, and the equipment is on an airplane with an engineer because they didn't want to take things that are assigned to them. That meant a trip to the cal lab to pick through the dregs and wait for it to be tested & certified. while my work piled up.

Another job, I developed an improved intermod test process for the PRC77 and was told it couldn't be implemented. A month later, the SOB got a bonus equal to six months of my pre tax pay for 'his idea'. :(

I hope you learned the rule on that - NEVER show anyone how you're doing your new improvement till you're showing it to someone high enough on the food chain for your name to be remembered properly at Bonuses and Promotions time - at least a Vice President, and not 'Vice President of Paperclip Procurement'.

And you hide a camera and record the meeting, so they can't get away with developing Institutional Amnesia and claiming it as their own.

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Larry Jaques on Fri, 14 Jun 2013

06:07:45 -0700 typed in rec.crafts.metalworking the following:

Ah, the hat for ol' Sparky - the firehouse dog.

-- pyotr filipivich "With Age comes Wisdom. Although more often, Age travels alone."

Too many shorts on mine right now to really do a test, nothing inside the fence since last fall...there's probably only ~400 feet of wire total.

--but I suspect any sparking would be rather small lacking a short unless the fence is exceptionally long, in which case there should be only single spark unless any resultant capacitive charge has leaked back to ground potential for some reason prior to the next pulse cycles' having occurred.

O.K. You mean *pdf* page 151? The clickable links stop at about page 119 as shown by xpdf. Same page number in acrobat reader.

I wish the BAMA folks would fix the filenames so they don't have embedded spaces. A pain to fix. :-)

Anyway -- the basic part is pretty simple -- just a different groove width for the bottom vs the top (for the pull latch).

The most difficult part would be the grooves in the edges which are sort of like this (edge pointing up for ease of ASCII drawing):

|\ /| | | | | | ( ) | | |

This serves both to hold the snap-in side panels, and serves for the screws to thread into to hold the end plates in place.

The groove and the angled lead-in would be easy to do with a stack of three cutters on a horizontal mill (one pass for each side), but the rounded bottom would probably have to be done with something like a large dental burr -- and lots of coolant squirted down the groove.

Aside from that -- the pattern of the rectangular holes in the top can vary somewhat -- depending on whether clearance is needed for controls at the very top of the front panel. (This based on examination of only two examples -- a single-channel vertical plugin, and the text formatter for the logic analyzer.

Enjoy, DoN.

Nope! I dislike web-based fora, and particularly yahoo groups. (I've got a lot of that blocked from people trying to subscribe me to groups without my agreement. :-)

Not sure whether I have that one in my collection of sources or not. Lots of downloaded, printed, and comb-bound manuals. Lots of wear on the HP 4600dn printer. :-) (And lots of opinions about different formatting practices in offering scanned manuals. :-)

Enjoy, DoN.

since last fall...there's probably only ~400 feet of wire total.

fence is exceptionally long, in which case there should be only single spark unless any resultant capacitive charge has leaked back to ground potential for some reason prior to the next pulse cycles' having occurred. Hint - the "Weed Chopper" is an AC shocker. = BZZZZZZ BZZZZZZZ BZZZZZZ.

VERY effective.

Every self-respecting electrical junk scrounger should have a Megger:

I have the Hitachi original instead of that copy. The short-circuit output of my 500VDC model is a safe 1mA, and of course if it shocks you, you stop cranking. I've charged up a 20uF 660V motor run cap with it in a couple of minutes. jsw

It would only need to be round for about 1/2 to 3/4" for the screws. You might be able to do that with a short bit & a good drill press.

the fence since last fall...there's probably only ~400 feet of wire total.

unless the fence is exceptionally long, in which case there should be only single spark unless any resultant capacitive charge has leaked back to ground potential for some reason prior to the next pulse cycles' having occurred.

Very effective at starting fires too, which is why they've been banned in many localities for going on several decades.

The vast majority output a DC pulse nowadays.

I ordered the 1KV model that evening and it just arrived. It reads a needle width or two low on 100.0 and 201.3 MegOhms lab-quality resistors, plenty accurate for checking motor or transformer insulation breakdown or an electric fence wire.

I cranked it up to 800V connected to a Fluke DVM with 10 Meg input impedance, which decreases to 6 Meg above 500V, likely from a protection circuit. That is practically a short for the megger's 1000 MegOhm range. The HF DVM's input is 1 Meg.

It's controllable to within 5V when charging the 20uF motor cap, with the Fluke DVM indicating the voltage, so it could be used to check or reform AC line voltage capacitors. The large computer electrolytics I've reformed required 5-10mA for many minutes, too much for this.

I could roughly measure the reverse breakdown of a 100V Radio Shack diode with it, 150V~200V on the Fluke at 20~30uA on a HF DVM in series, but the output isn't steady enough to hold within 10uA while cranking slowly. The voltmeter draws off 20uA at 200V so the diode reverse current was around 10uA.

1000V should be enough to check the breakdown of MOSFETs on an inverter welder. The Reverse Leakage parameter gives you an idea of how much reverse current the device should handle without damage. The megger's short-circuit current is 1mA.

The meters on these sense both voltage and current and indicate the ratio, which is resistance, so the cranking speed and output voltage don't affect the Ohms reading very much.

jsw

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I was thinking that until I realized that the side panels need at least the outer half of the round part for the edges to snap into. And those occur at several points along the side panels.

Enjoy, DoN.