Paul D. Agarwal

The GM High-Performance Induction Motor Drive System

The recent advances in the power handling capacity of semiconductor devices make it possible to replace dc and ac commutator machines for variable-speed applications by high-speed, lightweight, squirrel-cage induction motors. This paper describes a controlled slip-frequency system which eliminates the low-starting torque, low-power factor, and the low efficiency at lower speeds, normally associated with induction motors. The development program at the General Motors Research Laboratories that resulted in fabrication of the experimental electric vehicles, GM Electrovair and Electrovan (exhibited in October 1966), is described chronologically.

Programmable Energy Ignition System For Engine Optimization

This new ignition system uses inductive-discharge to strike the arc and, together with transformer action, sustains the arc from a single coil for any duration. Its principal features are: (1) programable arc duration, (2) high arc current for full arc period, (3) fast voltage rise, (4) low average battery current drain, (5) no intermediate power supply, and (6) since it uses inductive storage, it can be integrated into present electronic systems if the need is proven. Limited test results are presented to show the effect of arc duration on engine operation. /GMRL/

Induction Motor Control Scheme for Battery-Powered Electric Car (GM-Electrovair I)

Several experimental vehicles have been built by the General Motors Corporation to investigate the technical feasibility of a battery-powered electric car using a variable speed induction motor. This paper describes the control scheme for the first experimental car?Electrovair I.

Evaluation of fixed and moving primary linear induction motor systems

Linear induction motors being proposed for high-speed ground transportation may have their primaries carried on board the vehicle or embedded in the guideway. This paper evaluates various aspects, such as power requirements, power switching and controls, utilization factor, efficiency and cost, etc., for these two alternatives and provides the basic format on which relative merits of various systems can be readily evaluated. The analysis shows that, in the fixed primary system, it is economically impractical to energize sections of the roadbed substantially longer than the vehicle. Even when the primaries in the roadbed are energized in sections of minimum length, the cost of the linear induction motor and additional switching and power network for the fixed primary system is an order of magnitude higher than that for the moving primary system.

Relative field gradient at the edge of an electrode in a 4-electrode system

In this paper, relative electric field gradient at the edge of an electrode in a 4-electrode system is evaluated by the Schwarz-Christoffel (S-C) transformation. Several cases for different spacings between the electrodes and with different potentials are analyzed and results presented in the form of curves. The Monte Carlo technique was used to evaluate the integration constant, and results show that the field gradient is relatively high if the edge lies within a narrow range which should be avoided if high stresses are to be eliminated.