The Model 2522 continuously monitors 3-phase power lines for abnormal conditions. When properly adjusted, the Model 2522 will detect phase loss on a loaded motor even when regenerated voltage is present.

This unit consists of a solid-state voltage and phase-angle sensing circuit, driving an electromechanical relay with DPDT contacts. When correct voltage and phase rotation are applied, the internal relay will energize. A fault condition will de-energize the relay. When the fault is corrected the Model 2522 will reset.

Both automatic and manual reset versions are available. The Model 2522 does not require a neutral connection, and can be used with Wye or Delta systems. Two versions cover 120V, 208/240V, and 60Hz. Adjustment ranges are sufficiently wide to allow for proper adjustment to existing conditions. A failure indicator is provided to aid in adjustment and system troubleshooting.