Abstract: A fault isolation system for a three-phase induction motor drive system includes an inverter to convert direct-current power from a battery into alternating current for the three phases of the motor. The inverter contains six semiconductor switches, two for each phase of the motor, as is conventional in the art of induction motor control. Further, the inverter contains two additional semiconductor switches. These switches form an output connected, via a dummy load in parallel with a third additional semiconductor switch, to the neutral connection of the motor. In the event that any of the six conventional switches in the inverter become short-circuited, the four switches in the other two phases of the inverter as well as the two additional switches are actuated to generate current sufficient to blow a fuse connected in series with the output of the inverter coupled to the short-circuited switch.

Abstract: A fail-safe variable damping suspension system for a motor vehicle controls the oscillatory spring movements of each wheel via a permanent magnet rotary electric machine which is connected to machine control circuitry by normally open contacts of a relay. In the event of failure of the suspension system, the relay is released and the machine takes the form of a permanent magnet alternator which is connected to a defined load via normally closed contacts of the relay. Thus, in the event of a failure of the suspension system, the machine control circuitry is disabled and all shock absorbers are set to a fail-safe mode by the defined load upon closure of the normally closed contacts of the relay.

Abstract: An electrically powered suspension for a vehicle including a roadwheel and tire assembly, an electrically powered suspension unit having one end attached to the roadwheel and tire assembly and the other end attached to the chassis of the vehicle, with the suspension unit including an electric motor for positioning the roadwheel with respect to the chassis, and a controller for operating the electric motor so as to control the vertical movement of the wheel and tire assembly with respect to the vehicle's chassis. The electric motor may include either a linear or rotating electric motor, acting either alone or in parallel with a static load carrying device such as a fluid or coil spring.