Why Choose the ABB CM-PAS.41S Three-Phase Monitoring Relay?
The ABB CM-PAS.41S (1SVR730774R3300) is an industrial three-phase monitoring relay designed to detect phase failure, incorrect phase sequence and phase unbalance in three-phase electrical systems. Part of ABB's CM-PAS monitoring relay range, it provides dependable electrical supply supervision for motors, pumps, compressors, conveyors and industrial automation equipment.
Designed for a three-phase line-to-line voltage range of 300–500 V AC, the CM-PAS.41S is suitable for compatible industrial three-phase supplies. It continuously monitors the connected L1, L2 and L3 conductors using a True RMS (TRMS) measuring principle, helping identify supply conditions that could cause equipment malfunction, overheating or unexpected downtime.
The relay provides phase failure detection, phase sequence monitoring and adjustable phase unbalance monitoring. Its phase unbalance threshold can be configured using front-mounted operating controls, allowing the monitoring response to be matched to the requirements of the electrical installation.
A selectable ON-delayed tripping function, adjustable from 0.1 to 30 seconds or set to zero, enables coordination with industrial control circuits. The relay also features two change-over (SPDT) output contacts rated at 250 V / 4 A, providing flexible switching signals for compatible contactors, alarms and automation controllers.
Powered directly by the monitored three-phase supply, the ABB CM-PAS.41S requires no separate auxiliary power supply. Its compact 22.5 mm DIN rail-mounted housing, double-chamber cage screw terminals and three LED status indicators make it a practical solution for industrial motor control centres and electrical distribution panels.
Key Advantages
- Comprehensive three-phase supply monitoring for industrial electrical systems.
- Phase failure detection helps identify missing supply phases.
- Phase sequence monitoring helps detect incorrect phase rotation.
- Adjustable phase unbalance monitoring supports application-specific protection.
- Wide 300–500 V AC line-to-line measuring range.
- True RMS measuring principle provides dependable voltage evaluation.
- Two change-over output contacts support control and alarm signalling.
- 250 V / 4 A contact rating for appropriately rated control circuits.
- Adjustable ON-delay allows the response to be coordinated with the installation.
- 0-second or 0.1–30-second tripping delay offers flexible fault response.
- Self-powered operation eliminates the need for a separate auxiliary supply.
- Front-mounted adjustment controls simplify configuration and commissioning.
- Three LED indicators provide convenient operating status information.
- Compact 22.5 mm housing width saves control cabinet space.
- Double-chamber cage screw terminals support secure electrical connections.
- DIN rail mounting enables straightforward panel installation.
- Optional sealable transparent cover helps protect settings against unauthorised changes.
- Suitable for motor control centres, industrial machinery and three-phase electrical distribution systems.
Key Features
- ABB CM-PAS three-phase monitoring relay series.
- CM-PAS.41S model with screw-terminal connections.
- 300–500 V AC three-phase measuring range.
- 300–500 V AC rated control supply voltage.
- 50/60 Hz AC supply frequency.
- Phase failure detection.
- Phase sequence monitoring.
- Phase unbalance detection.
- Adjustable phase unbalance threshold, set as an absolute value.
- True RMS (TRMS) measuring principle.
- Two change-over (SPDT) relay contacts.
- 250 V / 4 A output contact rating.
- ON-delayed tripping function.
- 0 s or 0.1–30 s adjustable tripping delay.
- 200 ms start-up delay.
- Powered by the measuring circuit.
- Three LED status indicators.
- Front-mounted operating controls.
- Double-chamber cage screw-terminal technology.
- 22.5 mm compact housing width.
- Tool-free DIN rail mounting and removal.
- UL 94 V-0 housing material classification.
- Optional ABB COV.11 sealable transparent cover.
Technical Specifications
- Manufacturer: ABB
- Series: CM-PAS Three-Phase Monitoring Relays
- Model: CM-PAS.41S
- ABB order code: 1SVR730774R3300
- ABB product group: 310921-Measuring & Monitoring Relays
- Product type: Three-phase monitoring relay
- Monitoring functions: Phase failure, phase sequence and phase unbalance
- Rated control supply voltage: 3 × 300–500 V AC
- Measuring voltage range: 300–500 V AC line-to-line
- Supply type: AC
- Supply frequency: 50/60 Hz
- Monitored conductors: L1, L2 and L3
- Measuring principle: True RMS (TRMS)
- Phase failure monitoring: Yes
- Phase sequence monitoring: Yes
- Phase unbalance monitoring: Yes
- Phase unbalance threshold: Adjustable as an absolute value
- Tripping delay: 0 s or adjustable from 0.1 to 30 s
- Tripping delay type: ON-delay
- Start-up delay: 200 ms
- Auxiliary power supply: Not required; powered by the monitored circuit
- Output contacts: 2 change-over contacts
- Contact configuration: 2 c/o (2 × SPDT)
- Output contact rating: 250 V / 4 A
- Status indication: 3 LEDs
- Operating ambient temperature: -25 to +60 °C
- Storage temperature: -40 to +85 °C
- Terminal type: Screw terminals
- Connection technology: Double-chamber cage screw terminals
- Mounting type: DIN rail mounting
- Housing material classification: UL 94 V-0
- Product height: 85.6 mm
- Product width: 22.5 mm
- Product depth: 103.7 mm
- Dimensions (H × W × D): 85.6 × 22.5 × 103.7 mm
- Net weight: 0.132 kg
- EAN / GTIN: 4016779851800
- Minimum order quantity: 1 piece
- Customs tariff number: 85364900
- RoHS status: Following EU Directive 2011/65/EU
- Optional accessory: ABB COV.11 sealable transparent cover, 1SVR730005R0100
- Application category: Industrial three-phase supply and phase unbalance monitoring
Reliable Phase Failure, Phase Sequence and Phase Unbalance Monitoring
Industrial motors and automated machinery depend on stable, correctly connected three-phase electrical supplies. A missing phase, incorrect phase sequence or excessive voltage unbalance can cause overheating, reduced motor performance, abnormal mechanical operation and unexpected equipment stoppages. The ABB CM-PAS.41S three-phase monitoring relay helps identify these conditions and provides switching signals for appropriately designed motor control and alarm circuits.
The CM-PAS.41S monitors the voltages between L1, L2 and L3 within its specified 300–500 V AC line-to-line measuring range. It uses a True RMS measuring principle to evaluate the monitored supply and detect phase-related abnormalities.
Phase failure monitoring helps identify the loss of a supply phase. A three-phase motor operating under an abnormal phase condition may experience increased heating and reduced torque. By signalling a detected phase failure, the CM-PAS.41S enables the connected control system to initiate an appropriate response, such as operating an alarm or disconnecting the motor through a suitable external contactor.
Phase sequence monitoring helps detect incorrect phase rotation. This is particularly important for pumps, fans, compressors and conveyors, where reverse rotation can interfere with normal operation or damage connected machinery. The function is valuable during initial commissioning and following electrical maintenance or supply reconnection.
The relay also provides adjustable phase unbalance monitoring. Voltage unbalance occurs when the three phase-to-phase voltages differ beyond an acceptable level. Even relatively small supply unbalances can contribute to increased heating in three-phase motors. The CM-PAS.41S allows its unbalance threshold to be adjusted as an absolute value using the front-mounted controls.
Unlike voltage monitoring relays designed specifically to detect fixed overvoltage or undervoltage thresholds, the CM-PAS.41S focuses on phase failure, phase sequence and phase unbalance. It should therefore be selected according to these monitoring requirements rather than as a substitute for a dedicated overvoltage and undervoltage monitoring relay.
The adjustable ON-delay enables the monitoring response to be coordinated with the installation. Users can select instantaneous operation or configure a delay between 0.1 and 30 seconds. This can help prevent unnecessary switching caused by brief supply disturbances where a delayed response is suitable for the equipment and process.
With two change-over relay contacts, the CM-PAS.41S can interface with compatible contactors, programmable logic controllers, alarm devices and motor starter control circuits. The contacts are intended for control and signalling purposes and should not be used as a replacement for appropriately rated main power switching or short-circuit protection equipment.
The relay is powered directly by the monitored three-phase circuit, eliminating the need for a separate auxiliary supply. Its compact DIN rail housing, screw-terminal connections and front-mounted operating controls simplify integration into industrial control panels.
For maintenance and commissioning, three LED indicators provide visual information about the relay's operating state. An optional ABB COV.11 sealable transparent cover can also be fitted to help prevent unintended or unauthorised changes to the configured settings.
Typical Applications
- Three-phase supply monitoring in industrial electrical systems.
- Phase failure detection in motor starter circuits.
- Phase sequence monitoring during installation and commissioning.
- Phase unbalance detection in three-phase networks.
- Industrial motor control centres.
- Three-phase pumps and pumping installations.
- Compressors and refrigeration machinery.
- Industrial fans, blowers and ventilation equipment.
- Conveyor systems and material handling machinery.
- Automated manufacturing and production equipment.
- Industrial electrical distribution panels.
- Process control and industrial automation systems.
- OEM machinery requiring phase supervision.
- Alarm circuits for abnormal three-phase supply conditions.
- Industrial installations operating within the 300–500 V AC line-to-line measuring range.
