Model EX258B 3-Phase Monitor
The Model EX258B 3-Phase Monitor provides essential protection for industrial systems. This device detects critical conditions including phase loss, low voltage, and phase reversal, safeguarding connected equipment from potential damage. Its AUTO Reset functionality ensures continuous operation without manual intervention following a fault correction, minimizing downtime. With a robust five-year unconditional warranty and an expected relay life of 10 million mechanical operations, the EX258B offers long-term reliability in demanding applications. It operates effectively across a wide temperature range from -20° to +131° F, accommodating diverse industrial environments. The monitor's precise repeat accuracy of ± 0.1% of set point ensures consistent performance. Furthermore, its 380VAC nominal voltage and 300-400VAC adjustment range provide flexibility for various power configurations. The 50ms drop out response time ensures rapid fault detection.
3Ph Pm Factory Set
Specifications
| Reset Type | AUTO Reset |
|---|---|
| Nominal AC voltage (phase to phase) | 380VAC |
| Case Color | Yellow |
| Adjustment range | 300-400VAC |
| Frequency | 50Hz |
| Power consumption | 3.0W |
| Protection Feature | Detects phase loss, low voltage, phase reversal |
| Warranty | Five year unconditional warranty |
| Transient protection | 2500VAC for 10ms |
| Repeat accuracy | ± 0.1% of set point (fixed conditions) |
| Response time | 50ms drop out |
| Dead band | Approx. 2% |
| Output contacts | SPDT 10 amps at 240VAC resistive |
| Expected relay life (Mechanical) | 10 million operations |
| Expected relay life (Electrical) | 100,000 operations at rated load |
| Operating temperature | -20° to +131° F |
| Humidity tolerance | 0-97% w/o condensation |
| Enclosure material | ABS plastic cover |
| Mounting | 8-pin socket (**sold separately) |
| Agency approvals | UL Recognized* and CSA Certified |





