What is watt hour meter?

Answer 1

There are a couple of kinds of watt-hour meters: one is an electromechanical type (the one with the spinning wheel), and the other is a solid-state type. The solid-state types generally use a current transformer to measure the current produced in the current-carrying conductors, which means that the current carrying conductors need not be connected to the actual measuring device.) The electromechanical type uses an aluminum disc acted upon by two coils. One coil is positioned in such a way as to produce a magnetic flux in proportion to the voltage on the disc, and the other coil produces a magnetic flux proportional to the current. This causes the disc to rotate at a speed proportional to the power (voltage times current) being used. A permanent magnet is also installed in such a way as to exert an opposing force in proportion to the rotating speed of the disc. This causes the disc to slow down and stop when energy stops being used. The aluminum disc is also attached to a worm gear which drives the register.

Answer 2

A watt is the electric unit of power. Amperage x voltage = watt. 746 watts is one horsepower. A wattmeter measures power.

Answer

A wattmeter measures the voltage applied to a circuit, the resulting current, and the cosine of the angle between them, allowing it to indicate the true power of a circuit, in watts, regardless of the nature (resistive, inductive, or capacitive) of its load.

Incidentally, the watt is the SI unit for power, it is not the 'electric unit' of power, as there is no such thing as 'electric power'.

Answer 3

There are two main types of wattmeters. Electrodynamometers (electromechanical) and digital. Electromechanical meters are described below. The theory of electrodynamometers was developed by Elihu Thomson and Thomas Edison in 1888. Until then the only meter available was a zink plate meter (very unreliable and inaccurate) and a light meter which basically detected if the lights were on and turned on a clock if they were. When power is consumed, (such as in a light bulb) a current flows through the conductor. This current flow also produces a magnetic field which can be picked up using voltage and current coils within the electrodynamometer. When current flows it is induced onto the coils which causes a rotor to roate inside the stator casing of the meter. The rotation of the rotor causes the display dials to count up at certain values per rotation. This is all configured by the supplier of the meters or utility using magnets within the meter.

Answer 4

The wattmeter is an instrument to measure the electrical power.