Why Choose the ABB CM-EFS.2S Voltage Monitoring Relay?
The ABB CM-EFS.2S 1SVR730750R0400 is a versatile single-phase voltage monitoring relay designed for overvoltage and undervoltage supervision in AC and DC electrical systems. Part of ABB's CM single-phase monitoring range, it combines wide-range RMS voltage measurement with configurable relay outputs and timing functions for dependable industrial voltage monitoring.
The CM-EFS.2S provides four selectable measuring ranges of 3–30 V, 6–60 V, 30–300 V and 60–600 V, enabling one relay to cover a broad range of AC and DC monitoring applications. It supports window monitoring for both overvoltage and undervoltage conditions, with a fixed hysteresis of 5% of the selected threshold value.
A wide 24–240 V AC/DC control supply simplifies integration into industrial control systems. Two changeover contacts rated at 250 V / 4 A can be configured as 2 × 1 c/o for separate minimum and maximum signals or 1 × 2 c/o for a common signal, while selectable ON/OFF delay, latching and operating-principle functions provide additional application flexibility.
Key Advantages
- Wide 3–600 V RMS overall voltage monitoring capability.
- Suitable for both AC and DC voltage measurement.
- Four selectable ranges: 3–30 V, 6–60 V, 30–300 V and 60–600 V.
- Provides combined overvoltage and undervoltage window monitoring.
- Wide 24–240 V AC/DC control supply range.
- Configurable 2 × 1 c/o or 1 × 2 c/o output arrangement.
- Selectable ON- or OFF-delay with adjustable timing up to 30 s.
- Selectable open- or closed-circuit operating principle.
- Selectable latching function for retaining detected fault conditions.
- Compact 22.5 mm wide DIN-rail housing.
Key Features
- ABB CM-EFS.2S voltage monitoring relay.
- RMS measuring principle for AC and DC voltages.
- 24–240 V AC/DC rated control supply.
- Overvoltage and undervoltage monitoring.
- 3–30 V measuring range.
- 6–60 V measuring range.
- 30–300 V measuring range.
- 60–600 V measuring range.
- Fixed hysteresis of 5% of the threshold value.
- Tripping delay selectable between instantaneous and 0.1–30 s.
- Selectable ON- or OFF-delay operation.
- Selectable latching function.
- 2 changeover (SPDT) output contacts.
- Three LEDs for status indication.
- Screw connection technology.
Flexible AC/DC Overvoltage and Undervoltage Monitoring
The ABB CM-EFS.2S uses an RMS measuring principle to monitor AC and DC voltages across four selectable ranges extending from 3 to 600 V. Adjustable minimum and maximum thresholds enable window monitoring, allowing the relay to identify both undervoltage and overvoltage conditions and initiate the required control or alarm response.
The two changeover outputs can provide separate minimum and maximum threshold signals or operate together as a common fault signal. Selectable ON/OFF delay, open- or closed-circuit operation and latching provide further flexibility, making the CM-EFS.2S suitable for supply supervision, battery systems, industrial control voltages and other applications requiring reliable voltage monitoring.
Typical Applications
- Single-phase AC voltage monitoring.
- DC supply voltage supervision.
- Overvoltage and undervoltage protection circuits.
- Battery and DC power system monitoring.
- Industrial power supply supervision.
- Machine and equipment voltage monitoring.
- Automation and process control systems.
- Electrical control and distribution panels.
