Best Voltage Monitoring Relays AI pick

Chosen by an AI model from its trained knowledge, with its reasoning.

AI pick (line): ABB CM-ESS

The ABB CM-ESS single-phase voltage monitors offer adjustable over- and undervoltage thresholds with hysteresis and delay in a DIN-rail format.

Not for: Three-phase motor supplies where a phase monitor with unbalance detection is the right tool.

ICM Controls ICM493 (line)

The ICM493 line voltage monitor protects single-phase compressors and equipment from brownouts and surges with restart delays.

Not for: DIN-rail industrial panels.

Schneider Electric Zelio Control RM17UB (line)

Schneider's Zelio voltage control relays include models that supervise AC/DC control voltages in slim DIN housings.

Not for: Utility-side surge protection, which needs a surge protective device.

Measured voltage and type: Confirm the measuring range covers the nominal voltage with headroom on both thresholds, and whether the input is AC, DC or both. Range and input type vary widely between models.
Over, under or window: Choose undervoltage for brownout protection, overvoltage for equipment protection, or a window mode for both. Single-function units miss the other fault.
Hysteresis and delay: Look for adjustable or fixed hysteresis and a trip delay. Without them the relay chatters when voltage hovers near the setpoint.
Supply from measured circuit: Check whether the relay is powered from the monitored voltage or needs a separate supply. A self-powered relay cannot report a full outage on its own output.