1SVR740830R0300 ABB CM-ESS.1P Voltage Monitoring Relay 24–240 V AC/DC

Why Choose the ABB CM-ESS.1P Voltage Monitoring Relay?

The ABB CM-ESS.1P (1SVR740830R0300) is a versatile single-phase voltage monitoring relay designed to supervise AC and DC voltage levels in industrial electrical installations, machinery and automation systems. Part of ABB's CM-ESS measuring and monitoring relay range, it provides configurable overvoltage or undervoltage monitoring to help detect abnormal electrical conditions before they affect connected equipment.

Operating from a wide-range 24–240 V AC/DC control supply, the CM-ESS.1P offers four selectable voltage measuring ranges: 3–30 V, 6–60 V, 30–300 V and 60–600 V. Its RMS measuring principle supports monitoring of both AC and DC voltages, while an adjustable switching threshold and 3–30% hysteresis allow the response to be tailored to the application.

The relay features one changeover (SPDT) output contact rated at 250 V / 4 A and operates according to the open-circuit principle. With ABB's maintenance-free Easy Connect push-in terminals, front-mounted adjustment controls and a compact 22.5 mm DIN rail housing, the CM-ESS.1P is suitable for industrial control panels, OEM machinery, electrical distribution equipment and voltage-dependent automation systems.

Key Advantages

• Reliable AC and DC voltage monitoring for industrial electrical and automation systems.
• Wide-range 24–240 V AC/DC supply supports flexible installation.
• Four selectable measuring ranges cover voltages from 3 to 600 V.
• Overvoltage or undervoltage monitoring selectable to suit the application.
• Adjustable voltage threshold allows application-specific monitoring.
• Adjustable hysteresis from 3–30% helps prevent repeated switching near the threshold.
• RMS measuring principle supports AC and DC voltage supervision.
• One changeover (SPDT) contact rated at 250 V / 4 A.
• Open-circuit operating principle provides a defined switching response.
• Separate supply and measuring connections support flexible control circuit design.
• Easy Connect push-in terminals simplify electrical installation.
• Maintenance-free spring-clamp connections reduce routine terminal maintenance.
• 22.5 mm DIN rail housing conserves control cabinet space.
• Front-mounted controls simplify monitoring configuration.
• Suitable for machinery, power supplies, control circuits and process equipment.
• Optional sealable transparent cover helps prevent unauthorised adjustments.

Key Features

• ABB CM-ESS.1P voltage monitoring relay.
• Manufacturer order code: 1SVR740830R0300.
• Rated control supply voltage: 24–240 V AC/DC.
• Monitoring functions: Overvoltage or undervoltage.
• Measuring range 1: 3–30 V AC/DC.
• Measuring range 2: 6–60 V AC/DC.
• Measuring range 3: 30–300 V AC/DC.
• Measuring range 4: 60–600 V AC/DC.
• Overall measuring capability: 3–600 V across selectable ranges.
• Measuring principle: RMS.
• Voltage threshold: Adjustable within the selected measuring range.
• Hysteresis: Adjustable from 3–30% of the threshold value.
• Operating principle: Open-circuit principle.
• Output configuration: 1 changeover (SPDT) contact.
• Contact rating: 250 V / 4 A.
• Connection technology: ABB Easy Connect push-in terminals.
• Housing protection rating: IP50.
• Terminal protection rating: IP20.
• Mounting: DIN rail.
• Housing width: 22.5 mm.
• Optional sealable transparent protective cover.

Technical Specifications

• Manufacturer: ABB
• Product series: CM-ESS
• Model: CM-ESS.1P
• ABB order code: 1SVR740830R0300
• ABB product group: 310921-Measuring & Monitoring Relays
• Product type: Single-phase voltage monitoring relay
• Rated control supply voltage: 24–240 V AC/DC
• Supply type: AC/DC
• Monitoring function: Overvoltage or undervoltage monitoring
• Measuring range 1: 3–30 V
• Measuring range 2: 6–60 V
• Measuring range 3: 30–300 V
• Measuring range 4: 60–600 V
• Measuring voltage type: AC and DC
• Measuring principle: RMS
• Voltage threshold adjustment: Adjustable within the selected measuring range
• Hysteresis adjustment: 3–30% of the threshold value
• Operating principle: Open-circuit principle
• Output contacts: 1 changeover (SPDT)
• Output contact rating: 250 V / 4 A
• UL/CSA contact rating: B300
• Maximum UL/CSA output operating voltage: 300 V AC
• Rated insulation voltage, supply to measuring circuit: 600 V
• Rated insulation voltage, measuring to output circuit: 600 V
• Rated insulation voltage, supply to output circuit: 250 V
• Terminal type: Easy Connect push-in terminals
• Connection technology: Screwless spring-clamp connection
• Housing protection rating: IP50
• Terminal protection rating: IP20
• Mounting type: DIN rail mounting
• Operating ambient temperature: −20 to +60 °C
• Storage temperature: −40 to +85 °C
• Dimensions (H × W × D): 85.6 × 22.5 × 103.7 mm
• Product net weight: 0.126 kg
• EAN: 4016779852395
• Customs tariff number: 85364900

Versatile AC and DC Voltage Monitoring

The ABB CM-ESS.1P provides flexible voltage supervision for industrial control systems by monitoring the voltage applied to its measuring input and comparing it with an adjustable threshold.

The relay supports both AC and DC voltage monitoring, making it suitable for a broad range of applications, including industrial power supplies, control circuits, electrical distribution equipment and automation systems.

Its four selectable measuring ranges—3–30 V, 6–60 V, 30–300 V and 60–600 V—allow one relay type to cover a wide range of voltage monitoring requirements. The correct measuring range must be selected for the voltage being supervised.

The RMS measuring principle provides evaluation of the monitored voltage, while the adjustable threshold determines when the relay changes its output state.

The CM-ESS.1P is a single-phase voltage monitoring relay. It is not a dedicated three-phase phase sequence or phase unbalance monitoring device.

Configurable Overvoltage and Undervoltage Monitoring

The CM-ESS.1P can be configured for either overvoltage or undervoltage monitoring, allowing it to supervise different electrical operating conditions.

In overvoltage mode, the relay monitors whether the measured voltage exceeds the selected threshold. This is useful for detecting excessive voltage conditions that may affect connected equipment.

In undervoltage mode, the relay monitors whether the measured voltage falls below the selected threshold. This can help identify supply deterioration, insufficient voltage or abnormal conditions in electrical control circuits.

The selected monitoring function determines how the output contact responds to the measured voltage. The relay can be connected to suitable control and alarm circuits to provide a switching signal when the configured voltage condition is detected.

Because the CM-ESS.1P is a single-function model, it monitors overvoltage or undervoltage according to the selected configuration rather than providing two independently adjustable voltage thresholds simultaneously.

Adjustable Hysteresis for Stable Switching

The CM-ESS.1P features an adjustable hysteresis range of 3–30% of the configured voltage threshold.

Hysteresis creates a difference between the voltage level at which the relay changes state and the voltage level at which it returns to its previous state. This helps prevent repeated contact switching when the monitored voltage fluctuates close to the selected threshold.

For example, where a control supply experiences minor variations during normal operation, an appropriately selected hysteresis setting can help maintain stable monitoring behaviour without unnecessary switching.

The ability to adjust both the voltage threshold and hysteresis allows the CM-ESS.1P to be configured for a variety of industrial electrical conditions.

Hysteresis settings should be selected according to the acceptable voltage limits of the connected equipment and the requirements of the complete control system.

Open-Circuit Operating Principle and Changeover Output

The ABB CM-ESS.1P operates according to the open-circuit principle. Under this operating arrangement, the output relay changes state when the configured monitoring condition is reached.

Its single changeover (SPDT) contact provides both normally open and normally closed switching paths through a common terminal, allowing the output to be integrated into suitable control circuits.

The contact is rated at 250 V / 4 A and can be used with compatible PLC inputs, alarm circuits, contactor controls and other industrial signalling equipment.

The relay provides monitoring and switching signals; it does not directly regulate the measured voltage or replace appropriately selected overcurrent protection, surge protection or other electrical protective devices.

Easy Connect Push-In Terminals and Compact DIN Rail Installation

The CM-ESS.1P features ABB's Easy Connect Technology, using screwless push-in terminals for efficient electrical installation.

The spring-clamp connection system provides secure, maintenance-free electrical connections when correctly installed and reduces the need for conventional screw terminal tightening. This is particularly beneficial in industrial control cabinet assembly and OEM machinery production.

Its compact dimensions of 85.6 × 22.5 × 103.7 mm allow the relay to occupy just 22.5 mm of DIN rail width, helping conserve valuable panel space.

The device features an IP50 housing and IP20 terminals, with an operating ambient temperature range of −20 to +60 °C.

Front-mounted controls provide access to the monitoring function, measuring range, threshold and hysteresis settings. An optional sealable transparent cover is available to help protect against unauthorised adjustments.

Typical Applications

• Single-phase AC voltage monitoring in industrial electrical systems.
• DC voltage monitoring in automation and control circuits.
• Overvoltage detection for industrial equipment.
• Undervoltage monitoring for control power supplies.
• Industrial electrical distribution panels.
• Machinery control cabinets and automation enclosures.
• PLC-based voltage fault signalling.
• Industrial power supply supervision.
• Voltage monitoring in manufacturing equipment.
• Electrical control circuits requiring adjustable switching thresholds.
• Battery-backed DC control systems within the specified measuring ranges.
• Equipment requiring adjustable hysteresis to prevent contact chatter.
• OEM machinery with AC or DC voltage supervision requirements.
• Industrial alarm and monitoring systems.
• DIN rail panels requiring compact push-in terminal relays.
• Electrical installations using 24–240 V AC/DC control supplies.