Static Electricity and DCC

[tetters]

A curious thing happened a couple times this weekend. I've been busy sculpting roadbed contours and sanding wood ties. The subsequent dust left over has forced me to vaccum the layout several times.

Oddly enough whenever I've run the vaccum over the areas of completed track work something interesting happens...the power is still there...however the locos do not respond.

No electrical short, cab seemingly works fine, just no power to the locos.

The only thing I can guess is that my mighty Shop Vac is producing a considerable amount of static electricity when run over the tracks. The static buildup seemingly interferes with communications to the decoders in the locos. The remedy is simple...power off and then back on again which I assume releases the static charge from the tracks. It happened twice before I clued into what might be going on. Thus whenever I've vaccumed since, I've cut power to the tracks just incase too much build-up causes a decoder to go blooey or something worse. So far the problem has not re-occured since adopting this practice.

I wonder if anyone else has encountered this before and if it's cost them in the end? I hope I haven't done any long term damage to any of my DCC components.

 

[nkp174]

Interesting.

 

[tetters]

Yeah...I guess I should explain the why I think it is static electricity.

Simply...the hairs on my arms started to stand up when I vacuumed the trackwork. Looks and feels kinda funny. No power to the track...no static build up.

 

[nkp174]

Is this a common shop vac where the motor is on the floor?


I could see where the movement of the metallic filings through the field produced by the transformer could be altered...it's basic induction...but I don't know enough about the DCC signals to know why it is being affected...

 

[tetters]

Yeppers. An 8 gal. 4 hp (peak).

It's an NCE Power Cab. I'm wondering if the static electricity interferes with the digital signal being sent along the rails to the loco. Scrambles the message.

Honestly, a part of me wants to test the theory one more time, however I also don't want to tempt fate. I can't really afford to replace anything at this moment just incase something bad does happen.

I'm almost ready to e-mail the manufacturer to see if they have come across anything similar or have any info on it. My curiosity has got the best of me on this one.

 

[nachoman]

It could be that a static electricity signal is somehow tripping a hypothetical "circuit breaker" of sorts - in other word, confusing the circuitry. If I remember correctly, some CMOS logic chips used to be very sensitive to static electricity. We had a commodore 64 when I was a kid, and several times one of the processor chips went bad because of static electricity dishcharge from your body when you touched the "on" switch. I remember my dad rigging a ground near the switch so that your finger would touch the ground before touching the switch, thus protecting the computer.

Kevin

 

[Jim Krause]

One of the bugaboo's of modern avaition electronics (and other areas) is static electricity. Thats the reason for the anti static plastic wrappings on a lot of new computer components. The micro minaturizing of various components and the low current required to make them function can cause problems from outside sources.

 

[RobertInOntario]

I had a strange thing happen on my track this weekend. At least it seemed strange to me.

I replaced a turnout, so I had been sawing and cutting my track with my Atlas saw. After I'd added the new switch, my locos would spark just before where I had been working (not on the switch but a few inches before it). As they travelled by, you'd see bright sparks coming from their wheels.

This happened with one of my old (1960s) locos as well as a couple of my modern ones. I then vacuumed the area thoroughly and that seemed to solve it. This might have been caused by fine metal shavings from my sawing? ... yet I'd never had this happen before. (BTW, I'm still on DC, but you're problem reminded me of this one.)

Rob