Time Mark Corp. 258B-240VAC Three-Phase Monitor

Time Mark 258B-240VAC Three-Phase Monitor continuously supervises 208–240 VAC three‑phase power systems for phase loss, phase reversal, and undervoltage conditions and automatically de-energizes its SPDT output relay to protect motors and industrial equipment from damaging power abnormalities. This solid‑state monitor supports Wye or Delta configurations without a neutral connection and is designed for installation in motor control centers, HVAC equipment, pumps, compressors, conveyors, and other process machinery where dependable three‑phase power monitoring helps prevent motor damage and production interruptions. Key specifications include a 10 A resistive SPDT output at 240 VAC, 2.4 W power consumption, a 50 ms dropout response time, and ±0.1% repeat accuracy with a dead band of approximately 2%. The device accepts a nominal 208–240 VAC (phase‑to‑phase) input with a voltage adjustment range of 160–240 VAC at 60 Hz. It mounts in an 8‑pin plug‑in socket, and its status LEDs show TRIP and NORM. Operating from −20°F to +131°F (−29°C to +55°C), the 258B‑240VAC is UL Recognized and CSA Certified and remains compatible with Wye/Delta systems that do not require a neutral. Common replacements include Time Mark 258BM‑240VAC, A258B‑480VAC, and B258B‑120VAC.