- High efficiency
- Environmental Resistance
- High torque
What are the latest developments
in compact AC motors?
AC motors do not usually receive very much
attention, but, actually, there have been some
amazing advances in this area over the last few
years. This article covers the latest developments,
focusing mainly on compact motors under 90 W
(90 mm square mounting dimensions).
The era of energy-efficiency regulations
for medium and large motors has arrived
Let’s start with a look at the three-phase motor.
Three-phase motors cover a wide output power
range, from compact to large, and have many
advantages over single-phase motors, including
greater efficiency, higher starting torque and no
need for a capacitor to operate. And when it comes
to changing speed, the three-phase motor’s current
popularity can probably be explained by the fact that
versatile speed control can be achieved by simply
combining it with an inverter.
One key development related to the three-phase
motor is the progress being made around the world in
adopting regulations for motor-operating efficiency. It
is said that motor applications account for about 30–
40% of total global power consumption, so the trend is
toward more stringent efficiency regulations – starting
with power-consuming medium and large (0.75 kW
and higher) motors. This includes Japan, which until
recently did not have strict energy efficiency laws or
regulations, though this is finally changing.
Japan’s effort is distinguished by the Top Runner
Program, which is based on a revision of the Energy