Time Mark Corp A258B Phase Monitoring Relay 380-480VAC, 10A, SPDT, 240VAC 8 Pin

Description:

The Time Mark Corporation A258B Phase Monitoring Relay is designed to continuously monitor 380–480 VAC three-phase power systems for phase loss, phase reversal, and undervoltage conditions to protect motors and critical industrial equipment. Commonly installed in motor control centers, pumps, compressors, HVAC systems, conveyors, and manufacturing machinery where reliable three-phase power monitoring is essential for safe operation. Maintenance teams, OEMs, and system integrators use the A258B for replacement, repair, retrofit, and preventive maintenance to minimize equipment damage and reduce unplanned downtime.

Applications:

The Time Mark A258B is a solid-state three-phase monitoring relay that continuously supervises Wye or Delta power systems without requiring a neutral connection and de-energizes its output relay whenever phase loss, phase reversal, or undervoltage conditions are detected. It is widely used in industrial automation systems, water and wastewater facilities, motor control panels, compressors, conveyors, HVAC equipment, and process machinery where dependable three-phase power monitoring helps prevent costly electrical failures and production interruptions.

Technical Specifications:

• Manufacturer: Time Mark Corporation
• Manufacturer Part Number (MPN): A258B
• Product Type: 3-Phase Monitoring Relay
• Nominal Voltage: 380–480 VAC (Phase-to-Phase)
• Voltage Adjustment Range: 380–480 VAC
• Frequency: 60 Hz
• Power Consumption: 3.7 W
• Phase Sensing: Phase Loss and Phase Reversal
• Voltage Protection: Undervoltage Monitoring
• Output Contacts: SPDT, 10 A at 240 VAC Resistive
• Mounting: 8-Pin Plug-In Socket
• Automatic Reset: Yes
• Repeat Accuracy: ±0.1% of Set Point
• Response Time: 50 ms Dropout
• Dead Band: Approximately 2%
• Enclosure Material: ABS Plastic
• Operating Temperature: -20°F to +131°F (-29°C to +55°C)
• Certifications: UL Recognized, CSA Certified
• Application: Three-phase motor, compressor, pump, conveyor, HVAC, and industrial equipment protection.

Common Replacements:

• Time Mark A258BM
• Time Mark EX258B
• Time Mark A257B