Modified induction motors `perform like PM machines`

Raser Technologies, the US company developing an AC induction motor technology with a performance said to be similar to permanent magnet machines, has announced several developments. The company has:

• received an award from the US Department of Energy to develop a flexible motor controller platform that could be applied to a wide range of motors, from less than 1kW up to about 75kW;

• been granted its first US patent, covering some aspects of its Symetron motor technology; and

• been awarded a contract by the US Army Research Laboratory to develop designs for two integrated "starter generator/alternators" (ISAs) that would be integrated into vehicle electrical systems to boost acceleration and generate power.

Raser`s motor technology is based on "a few simple changes" to conventional motor designs, which are said to yield significant increases in power, performance and efficiency, without using exotic materials. Raser claims that the Symetron motors deliver more torque than conventional motors at a lower cost per kilowatt, and in a smaller, lighter frame.

For example, Raser has modified a 40kW NEMA motor so that it now delivers a maximum output of 143kW (or 56kW continuously at 7,200 rpm, compared to the original rating of 15kW). The modified motor produces a maximum torque of 190Nm, compared to the original 40Nm, and a continuous torque of 74.3Nm, compared to 20Nm.

Raser has produced its motors in both pancake and axial designs and is targeting electric vehicle applications, in particular.