Why Choose the ABB CM-PAS.31P Three-Phase Monitoring Relay?
The ABB CM-PAS.31P is a compact three-phase monitoring relay designed to supervise critical phase conditions in three-phase electrical supplies. Supplied under ABB order code 1SVR740774R1300, it monitors phase failure, phase sequence and phase unbalance to help protect motors, machinery and electrical equipment against unsuitable supply conditions.
The CM-PAS.31P is designed for three-phase systems with a 160–300 V AC line-to-line measuring range, with the measuring voltage also serving as the relay's control supply. The phase-unbalance threshold is adjustable from 2–25%, allowing the protection level to be matched to the requirements of the connected equipment.
An adjustable tripping delay of 0 s or 0.1–30 s helps prevent unwanted operation during brief disturbances, while two changeover (SPDT) output contacts provide flexible integration with contactors, alarms and control systems. Easy Connect push-in terminals and a slim 22.5 mm DIN rail housing simplify installation in industrial control panels.
Key Advantages
- Monitors phase failure, phase sequence and phase unbalance.
- Designed for 3 × 160–300 V AC three-phase systems.
- 2–25% adjustable phase-unbalance threshold for application-specific protection.
- Adjustable 0 s or 0.1–30 s tripping delay.
- Fast 200 ms start-up delay.
- Two changeover (SPDT) contacts provide flexible control and signalling.
- Measuring voltage also provides the control supply, simplifying wiring.
- Maintenance-free Easy Connect push-in terminals.
- Compact 22.5 mm width conserves DIN rail space.
- Three LEDs provide clear operational-state indication.
Key Features
- ABB CM-PAS three-phase monitoring relay series.
- ABB order code 1SVR740774R1300.
- Phase failure detection.
- Phase sequence monitoring.
- Phase unbalance monitoring.
- 2–25% adjustable phase-unbalance threshold.
- 160–300 V AC line-to-line measuring range.
- Rated control supply voltage equal to the measuring voltage.
- 0 s or 0.1–30 s adjustable tripping delay.
- 200 ms start-up delay.
- 2 c/o (SPDT) output contacts.
- 250 V / 4 A output contact rating.
- Push-in / screwless terminal technology.
- Three LED indicators for operational states.
- Tool-free DIN rail mounting and removal.
Reliable Three-Phase Supply Monitoring
Three-phase motors and machinery can be affected by incorrect phase sequence, loss of a phase or excessive voltage unbalance. The ABB CM-PAS.31P continuously monitors these phase conditions and changes the state of its output contacts when the monitored supply moves outside the configured operating conditions, allowing connected control equipment to initiate an alarm or disconnect the load.
The adjustable 2–25% phase-unbalance threshold allows the relay to be configured for the required level of supply symmetry, while the selectable instantaneous or 0.1–30 s tripping delay helps distinguish persistent faults from short-duration disturbances. This combination provides flexible three-phase protection for motors, pumps, compressors and industrial machinery.
Typical Applications
- Three-phase motor protection circuits.
- Pumps, fans and ventilation systems.
- Compressors and refrigeration machinery.
- Conveyors and material handling systems.
- Industrial machinery and production equipment.
- Motor control centres and electrical control panels.
- Phase-sequence verification in three-phase installations.
- Applications requiring phase-failure and phase-unbalance supervision.
