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Does My Bike Induce Electricity?

Posted by Cliff on from the hidden-dangers-of-electrical-fields dept.

An anonymous reader asks: "I have a steel frame road bicycle and recently began riding on a path that parallels high-tension power lines for several miles. My question is: Does my bike induce an electric current by passing through the electric fields from the power lines? I normally ride the section at about 18 miles per hour, estimate the distance to the lines at about 75-100 feet, and think they're 200KV lines."

6 of 72 comments (clear)

  1. combusting hay by bryanthompson · · Score: 3, Funny

    Last year my physics teacher told me a story about a guy who was stacking hay bales under power lines. These weren't super-powerful powerlines, just regular ones alongside the road. Anyhow, the guy had a nice stack going when he was blown off his tractor by some mini lightning caused by the hay powerlines.
    The way he explained it, the hay on the ground built up a charge and it was just a matter of time before it discharged with the power lines. When he was stacking, he must have gotten the charged hay too close or something, and it shocked him.
    I suppose it's possible you're getting a little stray charge, but as long as you're not wearing a suit made of hay...

  2. Yes by LarryRiedel · · Score: 3, Funny

    It is also compressed in the direction of motion, warps time, and emits graviton pulses.

  3. No... by Anonymous Coward · · Score: 3, Interesting

    Translational symmetry guarantees that as you move parallel to the cables, nothing happens.

    Physics seems to provide an endless supply of April Fool's jokes! :)

  4. Hey Taco by tsa · · Score: 3, Funny

    Time to post that 'Evil bit' article again!

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  5. Depends by pclminion · · Score: 4, Interesting
    If the lines are AC (which is the usual case except for long distance transmission lines) then you should have an induced emf in the bike frame. The bike frame forms a conducting loop, and as the AC current oscillates in the transmission line it creates a magnetic field perpendicular to the wire, which oscillates at the same frequency. As this magnetic field passes through the bike frame loop it will induce an alternating current at the same frequency. Basically your bike frame is acting like a single-turn inductor.

    You can increase the induced emf by wrapping multiple turns of insulated magnet wire into a loop in the same orientation as the bike frame. Neglecting the finite resistivity of the wire, you will get twice as much emf every time you double the number of turns. But even with hundreds of turns we're still talking about millivolts or perhaps hundredths of a volt at most.

    If the line is DC, then there will be no induced emf since the magnetic field is not changing.

    The speed at which you ride the bike has no influence on the induced emf, unless you are travelling near light speed, in which case the apparent frequency of the AC will be reduced since you are "catching up" to the propagating waveform. But I don't think you could pedal that fast :-)

  6. Yes, but it's negligible by muon1183 · · Score: 3, Informative

    Yes, you do in fact get an induced current. However, as demonstrated vividly by a question on my final when I was taking first semester E&M, you need somewhere on the order of 200,000 loops of wire to get enough induced current to be worthwhile from 20,000V power lines. (The exact question was, is it feasible to steal power by placing a coil between two 20,000V power transmission lines.) I'm pretty sure you don't care about the negligible effects (unless you're paranoid, or your bike is composed of 200,000 loops of wire).

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