Search

Common-mode current generated by the pulse-width modulated (PWM) ac drive at low modulation index and higher switching frequency results in overheating of the precharge resistor of the silicon-controlled rectifier (SCR)-based rectifier. In this paper, two modifications are proposed for the operation of SCR-based rectifiers to significantly reduce the resistor overheating issue. The solution is cost and size effective when compared with alternative solutions. Experimental results are provided to show the reduction of common-mode current flow through the precharge resistor and the consequent reduction in its temperature. [ABSTRACT FROM AUTHOR]

Evaluates the electrostatic shielded induction motor (ESIM) that reduces rotor shaft voltages to levels below the bearing lubricant's electric field intensity breakdown level. Review of shaft voltages and the resulting bearing currents operated on pulsewidth modulated voltage source inverters; Theory of EMI; Three potential construction methods for the ESIM.

Examines the mechanical and electrical characteristics of the rolling bearings and converts them into models. Electrically induced bearing failures and the hertzian ellipse point contact area; Mechanical and lubricant characteristics and their effects on the bearing capacitance; Bearing current density and related life factors; Bearing life projections; Conclusions.