Engineering topics

Buchanan, E.

Publications and source records attributed to Buchanan, E..

4 records

NASA NTRS2010

Characterization of Photoreceivers for LISA

LISA will use quadrant photo receivers as front-end devices for the phase meter measuring the motion of drag-free test masses in both angular orientation and separation. We have set up a laboratory testbed for the characterization of photo receivers. Some of the limiting noise sources have been identified and their contribution has been either measured or determined from the measured data. We have built a photo receiver with a 0.5 mm diameter quadrant photodiode with an equivalent input noise of better than 1.8 pA/(square root of)Hz below 20 MHz and a 3 dB bandwidth of 34 MHz.

Cervantes, F. Guzman↗

NASA NTRS1984

Servo Lead Compensation

Circuit for continuously varying lead compensation in servosystem operative even when integrating amplifier goes into saturation.

Buchanan, E.↗

NASA NTRS1973

Logic controlled solid state switchgear

Logic controlled solid state circuit breakers and power transfer switches have been designed and built to demonstrate their use for 270 V dc power systems. This switchgear provides remote operation, automatic current level, and operates several orders of magnitude faster with much greater accuracy of response than conventional switchgear.

Buchanan, E.↗

NASA NTRS1973

Study of feasibility of solid-state electric switch gear for aircraft and spacecraft

The design of a solid-state circuit breaker that can be interconnected to a second breaker to form a transfer switch is presented. The breaker operates on a nominal 270-V dc circuit and controls power to loads of up to 15 A. Automatic overload trip is provided as a function of excess energy measured through the breaker and/or excess current through the breaker. After an overload trip, up to nine preprogrammable attempts to reclose may be tried with programmable delays between each attempt. The breaker or switch is remotely controllable. Test data on performance in the laboratory over temperatures from -45 to 100 C are provided. The feasibility of solid-state switch gear has been established.

Buchanan, E.↗