View Full Version : Electrostatic Discharge

22 Degree Halo
6th Jan 2013, 21:16

tony draper
6th Jan 2013, 22:03
Bee keepers get used to being stung,sewage workers get used to the smell of poo,but no one ever gets used to electric frights.

Noah Zark.
6th Jan 2013, 22:20
Back in the day, I used to do a variation of this, by holding the tungsten electrode of a tig welding torch, and pointing with a finger (on the same hand) at a non-conductive material (wood,etc.) pressing the footpedal, and sparks zizzed from end of finger to whatever you were pointing at.
Only lasted a few milliseconds though, 'cos it started getting kinnot!
P.S. Main welding power wouldn't fire up, because the earth cable was removed.

6th Jan 2013, 22:39
no one ever gets used to electric frights.
There's muscular retraction that occurs.

I've always pulled away from electric shocks, though I believe that some people get hefty doses with continued contact, some ultimately fatal.

Takan Inchovit
6th Jan 2013, 23:13
A bit like getting the sequence mixed up when testing spark plugs! :ouch:

7th Jan 2013, 01:49
I used to get somebody to try and adjust the car timing on an oldie by turning the distributor while the engine was idling. After they jumped back I would ask them if they could confirm the firing order through the fingers on their hand.

Most forgot in all the excitement

7th Jan 2013, 02:43
Not sure what the OP is trying to tell us. Anyone doing an esd test would certainly have the basic knowledge necessary to avoid those errors.

Nervous SLF
7th Jan 2013, 03:20
In telephone and telex exchanges it was recommended that staff running jumpers removed wedding rings. Some very nasty finger injuries occurred if the ring shorted out some terminals.Posters showing said injuries were sent around to warn people.

7th Jan 2013, 03:38
Ha ha ha....very funny 22

7th Jan 2013, 09:54
In telephone and telex exchanges

O happy days of long ago ! As a GPO T2A in the early 1960's I saw a spanner dropped across the main 52v dc busbar in the battery room. It never even paused as it changed from A Dull Silver Solid to A Glowing Red Liquid and continued its way to the floor.

(Leicester Free Lane GPO)

Windy Militant
7th Jan 2013, 12:49
There's muscular retraction that occurs.

I seem to recall that AC throws you off as the muscles can't spasm at 50hz.
However DC just pulls you in.

TIG welding once I stood the job on a rubber gasket the pipe fitters had left on the table, the start pulse does sting. Eventually the penny dropped as to why it was trying to earth through me. :O

As for static my Mum had one of those Aqua Vac wet n dry cleaners.
After complaints about electric shocks I checked it over to find that a combination of epoxy coated steel drum and nylon fans made for a Wimshurst machine par excellence. It could light up a 500v neon tester at 6 inches and draw sparks from same at 2 inches. I hooked up a length of sink plug hole chain to one of the lid clamps, which as long it touched ground solved the problem!;)

tony draper
7th Jan 2013, 13:35
The house keeps in Hotels used to wear all their pass keys on a chain round the waist,if you needed a key to be into a room they would drop the chain onto the floor for you to pickup,never just hand it over, those long nylon carpeted hotel corridors used to build up a hell of a belt.

7th Jan 2013, 14:12
Lots of years ago I worked in an office that had problems with static (those nice new Nylon carpets might have had something to do with it). We walked round the place clutching a bunch of keys and used one of the keys to earth ourselves before touching door handles (or shaking hands with someone). The problem got so bad that they bought a machine to water the carpets - not terribly successful as I recall.

tony draper
7th Jan 2013, 14:21
We used to install and service the Ladbrokes Betting Shops Electronic Show Board systems,the monitors used to get so scruffy with ciggy smoke they could not be seen and the cleaners refused go near em,first time you did a service you realized why,the spark could jump four inches and zap you.

7th Jan 2013, 14:22
Knew a nice young lady who worked at H. A. Rrods which at the time was fitted throughout with a synthetic carpet. The game there was to shuffle around the floor then ask a customer if the needed assistance, at the same time gently touching them, say on the elbow. :)

Cornish Jack
7th Jan 2013, 15:28
Static discharge always a problem on heli winching. In the 60s, at Thorney Island, we were tasked with deck winching with the Littlehampton lifeboat and Farnborough to measure discharges. I recall that one such was quoted as 175,000 volts!!! Not much amperage but could make the muscles twitch! A couple of years later at Valley I went down to the Pinnace after a fairly strenuous wet winching exercise, breathing heavily with my mouth open. Foolishly held onto the wire as I touched down and got a short between my teeth fillings!:eek: Interesting, but no wish to repeat.:ugh: