Inventors:
Frederick H. Blake - Mill Creek WA
C. David Long - Redmond WA
Arthur G. Collin - Seattle WA
Assignee:
Multipoint Control Systems, Inc. - Everett WA
International Classification:
H05B 3700
Abstract:
The invention disclosed here is an anti-cycling device for high-pressure sodium lamps. A current sensor continually monitors lamp current and outputs a low voltage signal to an amplifier. When lamp current increases, indicating a starting or recycling condition, the sensor's voltage output correspondingly increases, and the amplifier responds by amplifying such output and transmitting it to a second amplifier. The latter acts as a voltage comparator and compares the first amplifier's output with a threshold level. Each time the first amplifier's output exceeds the threshold, the second amplifier outputs a trigger signal. Such signal is counted over time, and if the number of counts reaches a certain number, the counter outputs a malfunction signal to a relay that cuts off power to the lamp. An easy-to-see LED simultaneously illuminates to indicate the cycling condition and the need for lamp maintenance.