Three-Phase Monitoring Relay Helps Prevent Premature Motor and Equipment Failures

Phil Black - PII Editor 25/09/2014

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ATC Diversified Electronics (ATC Diversified), a division of the Marsh Bellofram Group of Companies, today announced the global market introduction of its SLA Series, a family of high-reliability three-phase monitoring relays.

The series offers cost-effective protection from phase loss, under voltage, and phase reversal conditions that can contribute to premature equipment failure and downtime within motor control centers, critical motors and pumps, and other Delta and Wye systems.

The SLA Series can effectively monitor current ranges up to 480 VAC with ABC phase sequence. Models are available in choice of several enclosure styles, as well as with selection of fixed, lock shaft, or screwdriver adjustment. Series models are available with either SPDT (enclosure styles “A” and “N”) or DPDR (style “E”) output. An onboard LED illuminates when all conditions are at “normal”, for a quick and clear visual reference of system conditions. Most units also feature automatic reset (manual option available with “E” style enclosure).

UL listed versions are available upon request. NOTE: For UL Listed units with field wiring terminals, copper wire with 60°/75°C rating must be used for control circuitry connections. When a phase is lost while the motor is running, a condition known as regeneration occurs. Here, a voltage is induced into the open phase that is nearly equal in magnitude to the normal phase-to-phase voltage. However, with the exception of lightly loaded motors, enough change is detected by the SLA Series to provide required protection when properly adjusted.

The cost-effectiveness and versatility of the SLA Series make it ideal for a variety of applications, including water and wastewater pumps and motors, sewage plant booster control stations, grinders, irrigation equipment, oil and gas machinery, machine tooling, conveyors, HVAC/R, elevators and escalators, processing equipment, construction and agricultural machinery and wind power turbine monitoring.