Company Filing History:
1 out of 8 
1 out of 56 
1 out of 2,297 
Years Active: 1989-1996
Title: Innovations of Alexander S. Keir
Introduction
Alexander S. Keir is an accomplished inventor based in Chelmsford, MA, with a notable portfolio of two patents. His work primarily focuses on advancements in electrical engineering, particularly in inverter technology and power management circuits.
Latest Patents
Keir's latest patents include a "Soft switched three phase inverter with staggered resonant recovery." This invention features a resonant recovery circuit that effectively discharges switching energy losses stored in a snubber capacitor associated with each pole of an inverter. The discharged current is returned to the DC supply through an inductor coupled to the resonant recovery switch. In a multiple pole inverter, the snubber capacitors are sequentially discharged during the clock cycle of the switching frequency, allowing for the use of multiple recovery circuits in a multi-phase inverter. Another significant patent is the "Capacitive boost circuit for extending hold up time." This circuit is designed to extend the operation of an electrical load after the interruption of its power source. It includes bulk capacitors charged by the power source and regulated to a predetermined voltage near their peak-voltage rating. During normal operation, the bulk capacitors are isolated from the power source capacitors. When the power source is interrupted, the bulk capacitors provide hold-up power to the load, maximizing hold-up time for a given physical bulk capacitor size while ensuring consistent performance across varying power source voltages.
Career Highlights
Throughout his career, Alexander S. Keir has worked with prominent companies such as Kaman Electromagnetics Corporation and Newport News Shipbuilding and Dry Dock Company. His contributions to these organizations have significantly advanced their technological capabilities.
Collaborations
Keir has collaborated with notable professionals in his field, including John C. Berry, enhancing the innovation process through shared expertise and insights.
Conclusion
Alexander S. Keir's contributions to electrical engineering through his patents and career achievements highlight his role as a significant innovator in the field. His work continues to influence advancements in inverter technology and power management systems.
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