Re: Proximity sensor for RSG

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: "Jim Lux by way of Terry Fritz <teslalist-at-qwest-dot-net>" <jimlux-at-earthlink-dot-net>

For a commercially available item.. companies like Omron and Sick make nice 
optical sensors with the kind of bandwidth you need.

At 11:32 AM 3/20/2003 -0700, you wrote:
>Original poster: "by way of Terry Fritz <teslalist-at-qwest-dot-net>" 
><Marco.Denicolai-at-tellabs-dot-com>
>
>Hello all,
>
>I would like to add to Thor's rotating spark gap a position sensor to
>know when the rotating electrodes face the fixed ones. I don't need to
>know the absolute position (degrees), just an digital signal is enough.
>I'll use that to synchronize the primary capacitor charge and to count
>the bang amount.
>
>The RSG features a 30 cm diameter rotor, with 12 rotating electrodes (2%
>thorium doped tungsten, 0.5" in diameter). The motor is a 2850 rpm,
>achieving a maximum bang-rate of 570 breaks/s. I calculated:
>
>- min. face time = 1.27/(PI*30*2850/60) = 0.28 ms
>- min. period = 1/570 = 1.75 ms
>
>I was thinking to detect the rotating electrode proximity or painted
>black spots on the rotor side. I don't want to drill holes or whatever
>to the rotor.
>
>I need help in choosing the right proximity sensor: capacitive,
>inductive or magnetic? What will work? Anybody with experience on this?
>
>Regards