Dynamometer Type Wattmeter
This is also similar in design and principle to the
dynamometer type ammeter and voltmeter.
Pic 1
Construction: In the dynamometer type instrument is used as a wattmeter,
the fixed coil, which is divided into two equal portions, the fixed coils are
connected in series with the load and carry the circuit (or load) current,
therefore it is also called as current coil. The moving coils is connected
across the load and carries the current proportional to the voltage across the
circuit. Therefore, it is known as pressure coil or potential coil.
A high non-inductive resistance ‘R’ is connected in series
with the moving coil to limit current through it.