Symcom 460-L Symcom Phase Monitoring Relay. Littelfuse Symcom Phase Monitoring Relay, Series: 460, 190 to 480 VAC, 50/60 Hz Frequency, Form C Contact Configuration, DIN Rail Mounting, NEMA 1 Enclosure, 3.5 in H x 2.08 in W x 2.35 in D Dimensions. Additional Description: SYMC-460-L 3-PHASE VOLT MON/ 190-480V/ AD. Catalog Description: The 460 is a 3-phase voltage monitor that protects 190-480VAC or 475-600V, 50/60Hz motors regardless of size. The product provides a user selectable nominal voltage setpoint and the voltage monitor automatically senses line voltage. This unique microcontroller-based voltage and phase-sensing device constantly monitors the 3-phase voltages to detect harmful power line conditions such as low, high, and unbalanced voltage, loss of any phase, and phase reversal. When a harmful condition is detected, the 460 output relay is deactivated after a specified trip delay. The output relay reactivates after power line conditions return to an acceptable level for a specified amount of time (restart delay). The trip and restart delays prevent nuisance tripping due to rapidly fluctuating power line conditions. All 460 models feature adjustable 1-30 second trip delay, 1-500 second restart delay, 2-8% voltage unbalance trip point, and one form C contact except where noted..