Reactance coils 1 and 2 are connected into an a -с circuit. Force
F, applied to armature 3, bends springs, reducing the air gap
between the armature and the core of coil 1. The air gap between
armature 4 and the core of coil 2 is m a in ta in e d constant. Coils 1
and 2 are connected to windings of triple-wound transformer 5
in such manner that measuring instrument 6, connected to the
third w in d in g of the transformer, indicates the difference in
the currents in coils I and 2. This difference depends upon the
air gap between armature 3 and the core of coil 1, w hich, in
turn, depends upon the force F to be measured. Interchangeable
resistors 7 serve to establish the required lim its of measurement.
O w ing to tha use of two coils, the reading of instrument 6
does not depend upon variations in the voltage and frequency
in the circuit.
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