Model 258 Tester 258B Monitor

3phase Tester w/industrial-grade 3-phase power monitor relay designed to continuously safeguard electrical motors and systems against abnormal power line conditions. It effectively detects faults such as phase loss, phase reversal, and low voltage/under-voltage conditions, ensuring equipment remains undamaged by poor power quality.Core FunctionalityAdvanced Phase Sensing: Uses a solid-state voltage and phase-angle sensing circuit to protect equipment.Regenerated Voltage Detection: Detects complete phase loss on a loaded motor, even if the spinning motor recreates a ghost/regenerated voltage on the missing phase.Relay Output: Drives an electromechanical Single-Pole Double-Throw (SPDT) relay rated for 10 Amps at 240VAC.Operation Behavior: The internal relay energizes under healthy power conditions and de-energizes (drops out) within 50ms when a fault occurs.Universal Compatibility: Requires no neutral connection and works seamlessly on both Wye and Delta configurations.Model Variations & SpecificationsThe 258 Series uses color-coded outer ABS plastic enclosures to represent different voltage and operating parameters.ModelNominal VoltageCase ColorFrequencyAdjustment RangeB258B / B258BM120 VACGray60 Hz85–120 VAC258B / 258BM208/240 VACRed60 Hz160–240 VAC