Motor efficiency has become a major specification in today's
energy-conscious world. Small universal electric motors
typically have an efficiency of about 30%, while 2-kW three-
phase machines can reach efficiencies of 95% or higher — when
they are operated at near full load. Electric motors lose
efficiency in several areas, the most common being copper
losses, iron losses, stray losses, and mechanical losses. The
efficiency level of an electric motor depends on actual electric
motor load versus rated load. The highest efficiency occurs near
the rated load and falls off rapidly for under- and over-load
conditions. This is why proper motor sizing is needed for
greatest efficiency. This is true for the many electric
automobiles available now. Efficiency means range as well as
their very important effective MPG figure. A few key automotive
motors: Fiat goes electric The Fiat 500e is powered by a 111-hp
(83-kW) electric motor and floor-mounted 24-kWh lithium-ion
battery pack that provide up to 80 miles (129 km) of