Time Mark Corp. Model 258B 3-Phase Universal Phase Monitor w/Auto Reset

258B Series*

The Time Mark Model 258 continuously monitors 3-phase power lines for abnormal conditions. When properly adjusted, the Model 258 monitor will detect phase loss on a loaded motor even when regenerated voltage is present. This device consists of a solid-state voltage and phase-angle sensing circuit, driving an electromechanical relay. 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 monitor will automatically reset (Model 258B) or need to be manually reset (Model 258BM).

The Model 258 does not require a neutral connection and can be used with Wye or Delta systems. Voltage ranges are sufficiently wide to allow for proper adjustment to existing conditions. Both TRIP and NORM condition indicators are provided to aid in adjustment and system trouble-shooting.


  • Detects phase loss, phase reversal and low voltage
  • 50Hz, 60Hz and 400Hz models available
  • Automatic reset
  • 5 Year unconditional warranty
More Information
Display No
Features Automatic Reset
Manufacturer Time Mark Corporation
Measurement Phase Loss Sensing, Phase Reversal Sensing, Under Voltage Sensing
Type Phase Monitor
Additional Skus B258B, 258B, A258B, EX258B, B258B-400HZ, 258B-400HZ, EX258B-415V
Additional Details

*Pricing & appearance may vary based on configuration!* Please configure product above.

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