Abstract:
The watt hour meter is an instrument used in a
house or plant to measure electric power. The driving
force caused by the magnetic field and turning force,
which are generated by electric current, is represented
by revolutions of a disc. The number of revolutions
is transmitted by connecting its revolving axis to a
gear. Such a measuring instrument should be reliable
and stable with a minimum loss of electricity as well
as possibility of mass production at reasonable prices.
This measuring instrument should also have excellent
characteristics against possible errors due to
variations in current, voltage, temperature and frequency.
Its specifications include single-phase 2-
wire, single-phase 3-wire, three-phase 3-wire, three phase
4-wire, etc. for use both in houses and industries.