A good example of what happens with the winch cables can be found in the movie "Hunt for Red October" when they are lowering Ryan to the sub.
--Randy
Modeling the Reading Railroad in the 1950's
Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.
tomikawaTT When parking an aircraft, immediately after chocking one wheel the static ground was installed, first to bare metal on the bird, then to an approved static ring in the pavement. Sometimes that second connection could get pyrotechnic! Chuck (Modeling Central Japan in September, 1964 - in a Southern Nevada garage)
When parking an aircraft, immediately after chocking one wheel the static ground was installed, first to bare metal on the bird, then to an approved static ring in the pavement. Sometimes that second connection could get pyrotechnic!
Chuck (Modeling Central Japan in September, 1964 - in a Southern Nevada garage)
Chuck,
The aircraft reference reminded me of a warning that was given to ground personnel not to touch the winch line being lowered from a helicopter until it touches the ground. Maybe I saw this in a movie or something, but it stuck with me. I guess you can get a pretty good zap if you touch the line before it discharges the static.
Pretty neat stuff here:
http://realitypod.com/2011/03/helicopter-static-electricity-phenomenon-explained-corona-effect/
I have read about people who make repairs to live high tension lines from a helicopter by "tying off" to the line and essentially becoming one with the line voltage, like a bird on a wire! No thanks, I'll keep my present job...
Ed
Well, grounding the benchwork keeps charges from building up there - but it does nothing to stop charges building up on you. You must not have carpet in the train room, or wear the type of clothign that tends to generate static - or your wife uses a darn good fabric softener.
It's been so dry here - my one cat likes to come up on the bed for some scratches, well, in the dark I can see the sparks as I run my hand along her back.
Reading this thread made me realize that I haven't had any static problems with my layout, even though 10% humidity is considered high here. Is it because I have steel stud benchwork connected to ground through the 120VAC third wire? For whatever reason, I give thanks.
For Bruce,
Can you not have a static strap fitted under your wheel chair so that it doesn't tangle. We used to have them on the back bumpers of cars in the winter in the Peg. They are probably still available at Piston Ring or Birch Auto or C.T.
Kay.Div. south east of the Peg.
I used to deliver gasoline to service stations, the first thing we had to do was ground the truck before we loaded it with 8,900 gallons of gas. Something you had to learn before loading and unloading the stuff. They had video cameras all around the loading docks and they caught one employee using his cell, he no longer worked for the company. All it will take is that tiny little spark to teach folks not to use cell phones while pumping fuel.
That made me go look to see if there were any suggested solutions to the problem of wheelchair tires on carpets, and while there are a lot of mentions, there really are no colutions other than the generic "install a humidifier". Spraying the carpet with fabric softener or anti-static spray might help, although if you have any breathing issues I wouldn't spray any sort of thing in an enclosed space.
I too have a carpeted floor in the railway room. As an additional problem, my wheelchair has rubber wheels that are very good static generators. I can touch a lolly pole and discharge myself with the accompanying spark, wheel 3 feet more and I feel a spark to my rails. I tried a metal chain from my chair frame dragging on the carpet but it just got tangled in the wheels (front and back).
Long story short, the DCC system seems to be immune so far.
73
Bruce in the Peg
When I frist started working at the phone company electronic phone were just coming around. They used to refer to this as the pantyhose syndrome;phone rings secratary walks acrossed office answers phone; no more phone!
TophiasMakes me wonder if I could blow a decoder or any system equipment if I discharged to anything layout connected?
Worthless trivia:
The idea behind lightning rods on old farm houses was to provide a quick path to ground for the lightning to disapate so it didn't have to go through the house. They later found out, in some cases, those lightning rods acted as magnets for lightning!
Don - Specializing in layout DC->DCC conversions
Modeling C&O transition era and steel industries There's Nothing Like Big Steam!
My basement layout room is finished and has industrial (breathable) carpet over a pad but it is a static contributor. Fortunately I have a few lally columns in my basement and touch one whenever I pass one (by habbit by now). Probably 1/3 time there's a buzz. Makes me wonder if I could blow a decoder or any system equipment if I discharged to anything layout connected?
Just remember, a static strap is NOT directly connected to ground - there's a 10 megaohm resistor in there. This is to protect you in case the 'ground' terminal is miswired to the hot in the box.
So you can make a static discharge plate and put it near the panel, with a "touch here first" label. Attach a wire with a 10MOhm resistor and then connect it to ground. The power center for my computer has something like that, a little shiny "Touch me first" button internally wired to ground via said 10M resistor.
Big enough chunk of metal and you wouldn;t even need to wire it to anything - just touching the metal frame of my dining room chair is enough to discharge any accumulated charge, and they are not in any way connected to an earth ground. Enough people and the metal would accumulate charge faster than it bleeds off into the air.
Also a good reason to have the entire system connected to earth ground at ONE point and ONE POINT ONLY - multiple connections to ground in different places can result in ground loops and if you think you have wierd and unexplainable glitches in DCC to begin with... Some systems recommend a 'common' wire between various components, either a 'ground' terminal if provided ot the metal case of the booster or other device, using wire the same size as your main power bus, all going to that one piece of equipment that is also connected to the earth ground.
A friend of mine who was a radio tech for the Police dept. said to always wear a static strap connected to a ground of some sort before working ony any electrical stuff, and when using a probe have one end connected to the chassis and only use one hand to probe keeping the other hand in your pocket, that way any high current discharge does not go across the heart to ground. Someone should tell the cat.
Kay.Div.
DigitalGriffin There's a reason bus's have chains hanging down from the axels. It's to let the bus discharge static charge buildup every once in a while.
There's a reason bus's have chains hanging down from the axels. It's to let the bus discharge static charge buildup every once in a while.
Hi, Don
I remember a similar strip that J.C. Whitney and a few auto parts stores sold in the '50s & '60s that were supposed to eliminate static discharge. They even had a lightning bolt printed on them. The Ohio and Pennsylvania Turnpike booths had a stiff wire protruding up from the ground to discharge any potential so the toll collector wouldnt get shocked so often.
The upholstery on my GMC Sonoma was really nasty at producing high voltage! That's why they recommend you don't get back into your vehicle when pumping petrol (women seem to have a propensity for this!)
As Wobblinwheel says, microchips and high voltage are not good companions.
I worked for a while at an Allen-Bradley facility and they had a "clean room" with a special conductive flooring and everyone inside had to wear conductive booties and grounding wrist straps. One "oops" could wipe out thousands of dollars worth of microprocessers...
Again, just something to be aware of when we handle expensive DCC decoders and such...
Good day to all... Ed
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I had something similar happen recently. I was doing a fair bit of media blasting with baking soda in my booth, and when I was done, pulled out the shop-vac to clean up the mess.
I don't recall what touched what, but about half way through, I got a good poke and it popped the breaker for the plug the vacuum was plugged into !
I finished the job with no further incidents by keeping my finger on the metal screw of the electrical socket cover effectively grounding myself.
I was even getting a mild poke off the rails in the train room just by walking into the room. Like you, I didn't think that would be much good for anything connected to the rails ! I attached a short length of bare wire to the plug cover screw (which is grounded through the case) and just touch that first before anything else.
Mark.
¡ uʍop ǝpısdn sı ǝɹnʇɐuƃıs ʎɯ 'dlǝɥ
Static discharge can really screw with a micro chip!
Mike C.
We all have different abilitys to transfer a static charge. I knew a guy who had such dry skin he could put his bare hand between two poles in the main electric box and not get shocked.
Cacole, Your shoes are likely rubber soles (an insulator) Simply grabbing a metal pole, or touching the ground with your hands might help discharge you. You can also safely touch a ground plug with a one way diode to prevent back currents. But I usually don't recommend the later as people might connect to the wrong plug socket or hit an incorrectly wired up outlet. (I've seen it happen in home remodels).
Last weekend we took our HO scale, CVP Products' Easy DCC powered, modular layout to a venue with a carpeted floor. Several times throughout the day, when someone touched the Easy DCC panel the static buildup in their bodies caused the system to shut down. We realized what was happening but knew of no way to prevent the static, and there was nothing nearby that anyone could touch to discharge their bodies before touching the DCC control panel. Fortunately, no harm seems to have been caused to any of the locomotive decoders or the DCC system.
Hi Dave
That wet nose story reminds me of a guy I knew who would take a capacitor from an automobile distributor and charge it up and put it on the ground for the cat to sniff! Curiosity might have killed the cat but I don't encourage anybody to speed things along!
I met my first electrified fence when my dad and I went to the East Broad Top Railroad. He wanted to get some photos farther away from the right-of-way and while we waited for the train I, like the cat, had to touch the fence! Pow! Ain't 'gonna do THAT again!
Take care, Ed
Ouch! I do recall a very good friend, now deceased, who from time to time did express some concern about the dangers of working on his layout due to his having a pacemaker/defibrilator implant.
And I have distant recollections of some people claiming that a pet dog died when it "wet nosed" the live track on a Lionel layout.
Dave Nelson
Ouch, it hurt, too!
Last night, while making a few alterations to a yard lead and runaround, I was using a Stanley Surform rasp and had made a pretty good pile of crumbly rubberized cork roadbed. So I grab the shop vac and clean up the area and wouldn't 'ya know... POW sparks fly from my finger tip to the nearest rail!
Now I start to think about all the electronics upstream of my "discharge" and all the damage that anywhere from 4,000 to 25,000 volts of reverse current can do... I haven't fired up the layout yet today. I'm pretty sure everything will be OK—but 'ya never know!
A vacuum cleaner and the dry air this time of year (in some areas of the Country —my humidity is 35% indoors right now) makes for a perfect recipe for creating potential static. Dust like the cork and the extruded polystyrene we use on the layout are perfect, too for generating these high voltages! I have an extra long hose on the vacuum, too.
I just thought I'd pass this along as a heads-up for anyone doing any vacuum cleaning around the layout. If, by chance, I would have picked up a decoder equipped engine or touched any thing like a throttle I'm guessing I could have done some real damage... just something to keep in mind. Discharge yourself on something grounded AWAY from the layout!
Many years ago I was on the telephone (one of the old fashioned kind that had a wire connecting it to the wall) and I absent-mindedly wiped off some dust on the TV picture tube (one of the old fashioned CRT kind)... next thing I knew I felt like somebody shot my ear off! The static made a path from the ear piece and through my ear! Real Ouch!
The call was disconnected and the phone never worked after that (probably cooked the voice coil wires which are thin as angel hair).
I know Broadway Lion frequently brings up grounding in some of his examples of layout wiring... maybe this is good reasoning for that?
Just call me Sparky! Ed