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. The magnetic field of the fixed and moving coils react on one another causing the moving coil to turn about its axis. The movement of the coil is controlled by hair springs also lead the current into and out of the moving element. Damping torque is provided by the air friction. Working: When the instrument is connect...