Evaluation of UPS for intersection traffic signals with LEDs: findings for Myers PB-1250PC UPS

Madhav V. Chitturi, R. F. Benekohal

Research output: Book/Report/Conference proceedingTechnical report


Uninterruptible Power Supply (UPS) systems are used to power the intersection traffic signals that have Light Emitting Diode (LED) signal modules, in case of a power failure. The objective of this study was to test the PB-1250PC UPS manufactured by Myers Power Products and verify if it meets the Illinois DOT’s specification for UPS. Multiple tests with full load (approximately 700 W) and partial loads (flashing reds with about 350W) were conducted at room temperature to determine charge and discharge times. The time to fully charge the batteries was on average 14hrs 17min. The UPS powered a full load for 2hrs 15mins. When powering a full load, the UPS took 1hr 8min to reach 40% battery level. After reaching the 40% level, the UPS powered the flashing reds for 1hr 46min. Myers PB-1250PC UPS meets the majority of the IDOT Specification requirements. It has three major and some minor shortcomings that can be corrected to satisfy all IDOT Specification requirements. The major shortcomings of this model are: the model does not have a NO and NC contact closure for indicating inverter/charger failure: the manufacturer gives a 48 hr burn-in period to each unit instead of 100 hrs required by IDOT specification, the fan in the battery cabinet runs on 48VDC instead of AC power.
Original languageEnglish (US)
Place of PublicationUrbana, Ill
PublisherUniversity of Illinois Urbana-Champaign
StatePublished - 2003

Publication series

NameTraffic Operations Lab Series


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