According to E Z Peaces :
DoN. Nichols wrote:


1055) Obviously a device for monitoring power line frequency. Power
line in part because of the lamp type screw base, and in part by
the frequncy range covered -- about 45Hz to 85 Hz, so it would
work with both common power line frequencies -- 50 Hz and 60 Hz.

It is a vibrating reed, and you adust the free length by turning
the knob at the other end of the the cylinder which mounts the
reed, moving the pointer (and a clamp to effectively shorten the
reed, thus changing the resonant frequency.

You screw it in, adjust the two angle clamps to make it easy to
read and to access the knob, turn on the outlet, and adjust the
knob for the maximum swing (on the arc-shaped scale under the
reed pointer.


I don't see why a device to measure electrical frequency would be marked
in degrees if you rotate it or tip it.

You first tune it for maximum sensitivity to the fequency in
question, then you shift the angles and compare the maximum swing of the
reed. This lets you determine in which axis the vibration at that
frequency is at a maximum, and thus what is the likely componenet
contributing to the vibration, so you can work on balancing it.

Enjoy,
DoN.
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