Time Mark Corp. Model A252B 3-Phase Power Monitor, SPST/SPDT, Socket Mount, 480V, 60 Hz


The Time Mark Model 252 3-Phase Monitor continuously monitors 3-phase power lines for abnormal conditions. When properly adjusted, the Model 252 will detect phase loss on a loaded motor even when regenerated voltage is present. The device consists of a solid-state voltage and phase-angle sensing circuit, driving an electromechanical relay with one SPDT and one SPST contact. 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 252 will automatically reset.

The Model 252 does not require a neutral connection and can be used with Wye or Delta systems. Four versions cover 120V (Model B252B), 208/240V (Model 252B) and 480V (A252B), 60Hz, and 380V (EX252B), 50Hz. Adjustment ranges are sufficiently wide to allow for proper adjustment to existing conditions. Two LED indicator are provided to aid in adjustment and system troubleshooting.


  • Model A252B = 480 VAC, 60 Hz (w/380-480 VAC Adjustment Range)
  • Detects phase loss, low voltage and phase reversal
  • Automatic reset
  • UL Approved
More Information
Display No
Features Automatic Reset
Manufacturer Time Mark Corporation
Measurement Phase Loss Sensing, Phase Reversal Sensing, Under Voltage Sensing
Type Phase Monitor
Copyright © Ram Meter, Inc | Instrumentation and Testing Equipment | Powered by Turtlehut™