Iota Engineering Co.

David G Light

William H Conley, Iii

An emergency lighting test system and method automatically schedules self tests and uses novel test methods to thoroughly test an emergency lighting system. An emergency lighting system comprises a fluorescent lamp, an inverter circuit and a backup power source (e.g. a battery). A microcontroller controls testing of the system and tracks time of day and date for scheduling tests of the lighting system. After a test is performed, the test reports are stored in memory. Two novel tests are used to evaluate the lighting system. A first test determines backup power source condition. The test samples the high frequency signal generated by the inverter circuit to determine an average peak voltage. The average peak voltage is indicative of backup power source voltage. If the average peak voltage falls below a predetermined lower limit, it indicates a backup power source failure. The lamp is turned off and a failure is flagged. A second test determines lamp and inverter condition. This test measures the frequency of the high frequency signal generated by the inverter circuit. The high frequency signal is filtered and divided down to a convenient frequency suitable for interfacing with the microcontroller. A frequency outside of a predetermined range indicates a failed lamp or failed inverter circuit. The lamp is turned off and a failure is flagged.

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Tucson, AZ, United States of America

David G Light