Quote:
Originally Posted by ThePillenwerfer
The problem I've had with trying to work it out is not knowing the inductance, and therefore the Inductive Reactance of bell coils.
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I got my figure for a type 59A bell movement by driving it with a 25Hz 90V supply via a resistor and a true RMS ammeter, and measuring the voltage across the bell-movement (and hence its impedance), the supply, and the resistor.
From this I could draw a triangle with each side representing the aforementioned voltages, and using the Cosine rule, extrapolated the in-phase and quadrature components for the bell-movement: typically 1776 + j2085, or a Z of 2739 at an angle of +50 degrees.
This differs from that of a bridged measurement because of the current and the 'in-phase' losses (eddy current and hysteresis losses) and gives an inductance of about 13H.