Nickel/Cadmium Aircraft Batteries: Battery Alarm Unit.
Abstract
Malfunctions in nickel/cadmium aircraft batteries which may lead to dangerous thermal problems are usually preceded by small atypical decreases in voltage of a single failing cell. Early detection of this decrease can provide time for suitable measures to be taken before other cells are damaged and catastrophic consequences occur. Also detection during battery shop operations can facilitate the screening out of defective cells. The battery alarm unit described in this paper was developed at DREO and is a simple device which monitors the cell voltages by comparing the voltage in one half of the battery with that of the other half. Only three connections to the battery are required. Atypical voltage changes in a single cell, of the order of 50 mV may be detected. The precise sensitivity may be varied by varying resistor values in the input network. The instrument has been found useful in the battery shop both for warning of failing cells in batteries being charged and for attracting attention to cells which show low capacity while being discharged. Presumably the instrument could be equally useful as an early warning device on aircraft. For such applications consideration must be given to questions of procedure, configuration and airworthy mechanical design. Also experience in the field is required on which to base decisions on the optimum sensitivity and whether aircraft and battery shop applications require the same sensitivities. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- Apr 01, 1977
- Accession Number
- ADA039521
Entities
People
- K. Feldman
- R. M. Hayashi
Organizations
- Defence Research and Development Canada