Permanent Magnet Geared Starters

A range of 4 pole ferrite magnet reduction gear starters is described with outputs of 1.0 kW, 1.4kW and 1.7 kW. These show substantial weight savings by comparison with present direct drive wound field starters. High intrinsic energy ferrite segments with innovative pole shields provide a high resistance to demagnetisation.

For lower power outputs, new designs of woundfield, direct drive starters provide the best cost/performance/weight compromise, geared ferrite magnet starters being lighter but too expensive. Direct drive ferrite magnet designs have inadequate stall torque to deal with hot starting problems.

The influence of Neodymium-Iron-Boron permanent magnets on starter design is discussed.