[sdiy] Serge and multiples

[Martin Czech]

:::I wonder what is causing this? What powers the train? Is either the train
:::or the track electrical?

Railway nerd mode on:
Err, yes, in europe most trains are electrical, I didn't mention it.
It's 15kV, 16 2/3 Hz (that's 50/3 Hz) and about 1000A or more.  cos PHI
is about 0 due to thyristor controlled motors. There will be quite a lot
of harmonics. It's a "mountain track", this means two engines, one at the
front, the other at the back, three or four waggons in between. I guess
there must be some anti slip control for the two engines. Single wire,
tracks and ground carry the current back.


back to EE mode:
Single wire, tracks and ground carry the current back.
Now the crt (vector v) points orthogonal towards the track.
B comes alternating from the ground or heaven (B enloses the wire
in a circular like pattern). v X B leads therefore to a horizontal
jittering image, experiment and theory matches ;->
Turning the monitor won't help, only tilt ;->

I guess the sound will not be too interesting.

Do you think that a "Helmholtz-coil" just a few dozend turns of copper
wire in a circular shape, diameter, say 15 cm will be a good B field
snooper? I could clamp that to scope.

I'm also interested in that big transformer station 30m east from me.
I can hear the hum (magnetostriction), but I doubt that there is
any field left in my living room. Anyway, I want to know.
Guitars are not more noisy then before moving house.
Except when approaching my scr controlled living room floor lamps.
(500 W cieling flood).

m.c.


:::
:::I'd be interested to know what sort of unusual audio-frequency electrical
:::signals you might be able to pickup from a passing train. Perhaps a guitar
:::pickup or something similar would give you an audio signal from the train?
:::If the train produces a field that shakes your monitor, it might possible
:::to record it this way.
:::
:::
:::Later,
:::Glen