Armstrong World Industries, Inc.

York International Corporation

Roy D Hoffer

Frank E Wills

Harold R Schnetzka, Ii

J Marshall Hemphill

A motor drive system for driving a single-phase PSC motor, in which the two motor windings are conductively isolated from each other, from a two phase power source. In one embodiment, the PSC motor is supplied from a two phase inverter circuit. The PSC motor is also connectable through a four-pole double-throw switch to either a single phase source including a run capacitor or the two phase inverter circuit.

AC motor drive system

A motor drive system for driving a conventional single phase PSC motor from a two-phase power source. In one embodiment, the PSC motor is supplied from a three-phase inverter that is controlled to generate two-phase power. In another embodiment, the PSC motor is connectable through a double-pole double-throw switch to either a single phase source including a run capacitor or a two-phase inverter source.

A limited power, gaseous discharge lighting system, particularly suitable for use with suspended ceilings and for safe installation without shock and/or fire hazard and for rearrangement by non-electricians without special tools or experience, the light output of which is controlled by an electronic controller which responds to the ambient light available. The system uses non-armored flexible cables to supply individual relocatable gaseous discharge lighting fixtures and dimmers, and the cables are individually plugged into receptacles which furnish power strictly limited to permit the safe use of the cables, plugs and receptacles. High frequency operation permits efficient operation with rated light output and an electronic controller furnishes additional versatility and economy.

Electronically dimmed power limited lighting system

A room lighting control system which controls the electrical power supplied to the artificial lighting in an area based on the ambient light available. A photocell controlled digital lamp dimming circuit with particularly high stability for time and temperature is combined with a slow response time to avoid short term adjustments. A digital counter is used to determine a large number of steps over the adjustment range and the driving clock operates at a very low frequency, so that changes in light level take a relatively long time, and it takes an exceptionally long time to span the entire adjustment range.

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Lancaster, PA, United States of America

Roy D Hoffer