Marathon Electric Manufacturing Corporation

Marathon Electric Mfg. Corp.

Gary L Schurter

Duane R Nolte

Stanley S Chula

Thomas H Coleman, Jr

Lowell R Stuebinger

An engine-driven alternator assembly includes an output winding having an internal impedance characteristic similar to a separate stationary ballast for high intensity discharge lamps. The output winding is direct connected to lamps in a mobile light tower application having four HID lamps. The alternator assembly includes four separate alternator units each having an output winding wound to establish the inherent internal impedance to provide a ballast source for the connected lamp. Each alternator unit has its rotor mounted on a common shaft connected to the shaft of the engine. Each alternator unit establishes an open circuit voltage to strike an arc across the HID lamp and then a sustaining voltage to maintain current flow as well as limiting the current to the lamp. The alternator unit has a high frequency output, preferably within 200 to 600 hertz. The alternator unit is a permanent magnet alternator, a switched reluctance alternator, an induction alternator, or a wound synchronous alternator. A full wave bridge may be connected across the alternator output to supply the limited direct current to the lamp, and the engine may be controlled to create the voltage change.

Special alternator assembly with an inherent ballast impedance

A centrifugal switch assembly for a single phase induction motor connects a start winding and/or start capacitors in circuit. A centrifugal actuator positions a contact unit on a cantilevered spring arm relative to an aligned fixed contact unit. Each contact unit is identically constructed with a cylindrical steel base and an outer contact button which defines a radial lip. A silicone rubber boot in the form of a tubular member having similar thick end hubs connected by a thin-wall convolution between the hubs to establish a flexible enclosure. The hubs are telescoped respectively over the contact bases with the same interference fit to totally enclose the contact units. The lips of the contact buttons lock the boot to the contact units. The boot length is greater than the spacing of the open contact units and the convolution is continuously deflected to create a closing force. A pressure relief pin hole is formed in a crease at the connection of the convolution and the hub secured to the fixed contact unit to allow air flow from the enclosed contacts and uninterrupted closure of the switch assembly.

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Wausau, WI, United States of America

Gary L Schurter