Electrostatic discharge on bus?

[bz]

Well, I rather ruled that out when I'd get a poke without it
on. Same thing with my boots. I get a poke when I wear shoes.

The instances do diminish in the summer time but then that's
normal.

Static electricity is worse when the humidity is low. When humidity is
high, even the air can act to discharge the charge.

Yup. What I don't understand is why I don't ground out completely
with the first poke. One of these days, I'm going to remember to
not turn around to lock the car and see if that recharges me. I
know it's a silly notion, but I have to rule out them out, too.

Some things act as capacitors and may need to be discharged more than once.

For example, the picture tube of a TV set. The glass of the tube acts as
the dielectric of a capacitor. When you work on a TV, you must be careful
to discharge the high voltage anode connection on the side of the bell.

After the tube has been discharged, as the glass relaxes and as distant
electric charges make their way to the conductive coating inside the glass,
the picture tube will 'build up' a charge again.

It is wise to leave your grounding strap connected for several minutes
before you start to handle the picture tube.



--
bz

please pardon my infinite ignorance, the set-of-things-I-do-not-know is an
infinite set.

[email protected] remove ch100-5 to avoid spam trap

 

[bz]

Right. So why can't I manage to get a discharge a second time
through my coat? If I can't do this a second time, then I'm
a walking spark when I pump gas. So far I always lock my car
before I pump gas to make sure I don't spark.

The pump handle is well grounded. As long as you maintain contact with the
pump or pump handle, you should be discharged. Make sure your car is
discharged by touching the metal part of the pump handle to the metal of
your car. Do this away from the tank filler area before you remove the gas
cap.

THEN open the fuel tank, insert the pump nozzle, and pump gas. Don't move
away from the car while pumping gas, or if you do, be sure and touch a
metal part of the car away from the gasoline tank, before you touch around
the nozzle. You do NOT want a spark around the nozzle, because gasoline
fumes mixed with air are exhausting from the tank as you fill it.

BTW, 1 gallon of gasoline, properly vaporized, has more explosive force
than a case of dynamite.

....

This is one of the many reasons I put hardware on my list as a
"guy thing".

I doubt the accuracy/univerality of 'guy thing'/'girl thing'
classifications, but understand why people feel that way.




--
bz

please pardon my infinite ignorance, the set-of-things-I-do-not-know is an
infinite set.

[email protected] remove ch100-5 to avoid spam trap

 

[w_tom]

Glen and some others have provided a good response. To add
to what he wrote:
The discharge means electricity. Charges are not
electricity. Neither you nor the bus alone accumulate
charges. Both do. Electricity flows from (or to) charges in
you to charges in the bus. The charges don't flow.
Electricity flows from and to charges of different potential.
Charges you may have created by sliding on the seat.

Even that little air gap between you and your hand was an
electrical conductor before your hand actually touched the
metal bar. Even the insulator air conducted electricity -
albeit only for a short distance.

Materials that some consider insulators may be conductors to
electricity of different voltages and current levels. When
discussing static electric discharges, some tables, linoleum
tile, some wall paints, concrete floor, etc all can be
conductors. Even the string on a kite that appears to be an
insulator at lower voltages can be a conductor at higher
voltages. Some things (ie glass) are better insulators than
others (wood). When you touched the pole, you made an
electric circuit between two differently charged materials -
therefore electricity flowed.

 

[Rich Grise]

Vehicles on rubber tyres can certainly become charged, though I'd
suspect the culprit is dust rather than air.

It's the friction between the tires (ahem ;-) ) and the road, just
like a Van der Graaf. I got into the habit of touching something
metal _while_ getting out of the car - that takes care of the pants/
car seat issue. Unfortunately, at that point the valet gets zapped.

I've also commonly seen multiple zaps from one charge - when you
draw a one-inch (2.5 cm) arc, it only conducts until enough charge
has bled off such that you can't sustain the arc.

But a 1/8" (1/2 cm) arc, no problem!

Cheers!
Rich