siemens
Siemens SIRIUS 3RS Temperature Monitoring Relay
Model: 3RS1040-1GD50
4-hour response · Pricing in SAR · Delivery across all KSA regions
3RS1040-1GD50 — Siemens SIRIUS 3RS Temperature Monitoring Relay
The Siemens SIRIUS 3RS is a DIN-rail mounted temperature monitoring relay providing setpoint-based thermal protection for motors, transformers, bearings, and process equipment using thermocouple, Pt100, Pt1000, or NTC thermistor temperature sensors. The 3RS family spans multiple variants covering single-channel and dual-channel monitoring, thermocouple types J, K, E, N, and R, and resistance sensor types Pt100 and Pt1000 in 2-wire and 3-wire connections — allowing the correct variant to be selected for the sensor type already installed in any motor or transformer without additional signal conditioning hardware.
The 3RS relay's operating principle is straightforward: two independently adjustable setpoints control the warning and trip relay outputs. The warning relay activates at the first threshold, alerting the operator or SCADA system; if the temperature continues to rise to the second setpoint, the trip relay de-energises the motor contactor. This two-tier response prevents nuisance motor trips on temporary overtemperature events while ensuring reliable protection against sustained overtemperature that causes winding insulation degradation. Supply voltage acceptance covers 24 V DC through 240 V AC, making the 3RS universally applicable across control panel designs.
In Saudi Arabia, the SIRIUS 3RS KSA is the standard thermal protection relay for large motors at SWCC desalination plants, SABIC petrochemical MCC motor feeders, and transformer winding protection panels across the Kingdom. Large motors above 75 kW in Saudi Aramco upstream facilities must comply with IEC 60034-1 thermal protection class designations, and the Pt100 sensor inputs of the 3RS provide the IEC-compliant protection that bimetal overload relays cannot achieve for high-value process motors. Temperature monitoring of dry-type transformers at industrial substations uses the 3RS Pt100 variant to monitor winding phases and trigger cooling fan activation before the trip threshold is reached.
Razz Middle East stocks SIRIUS 3RS relays in the most common thermocouple and RTD variants for same-week delivery. We supply complete thermal protection packages including sensor, relay, and motor protection panel wiring design support.
Technical Specifications
Full specifications for the 3RS1040-1GD50
- Sensor Types
- Pt100 (2/3-wire), Pt1000, NTC, TC types J/K/E/N/R
- Setpoint Range
- -50 to +400°C (Pt100); -200 to +1370°C (TC type K)
- Relay Outputs
- 1 warning + 1 trip (separate setpoints)
- Supply Voltage
- 24–240 V AC/DC universal
- Mounting
- DIN rail 22.5 mm width
- Response Time
- <1 s
- Contact Rating
- 5 A at 250 V AC
- Compliance
- IEC 60255, CE, UL
Key Features & Benefits
- Dual independent setpoints for warning and trip outputs provide a two-tier thermal protection response that alerts operators to rising motor temperatures before the trip threshold is reached, preventing nuisance trips on temporary overtemperature excursions.
- Universal supply voltage input (24–240 V AC/DC) allows a single relay variant to be used across the full range of control panel designs in Saudi Arabia without selecting different models for 24 V DC and 230 V AC panels.
- Pt100 and Pt1000 RTD inputs with 2-wire and 3-wire connection options cover the range of sensor types installed in large induction motors, dry-type transformers, and bearing housings at Saudi industrial facilities without additional transmitters.
- Thermocouple inputs covering types J, K, E, N, and R extend the 3RS application range to high-temperature process equipment monitoring, including kiln bearing temperature and furnace burner control at cement and steel plants.
- Compact 22.5 mm DIN rail footprint allows the 3RS to be installed in standard motor protection panels alongside motor starters without requiring additional panel width — essential for dense MCC motor feeder designs.
- IEC 60034-1 thermal protection class compliance when using embedded Pt100 winding sensors meets the thermal protection requirements for large motors in Saudi Aramco and SEC contractor installations where insurance certification demands IEC-compliant protection.
- LED status indicators for power, warning, and trip states provide immediate visual diagnostic information at the panel, reducing troubleshooting time for maintenance engineers at remote pump stations and transformer installations.
Industrial Applications in Saudi Arabia
- Large induction motor winding temperature protection at SWCC desalination high-pressure pump drives, where embedded Pt100 sensors in each stator phase provide early overtemperature warning before the winding insulation class is exceeded.
- Dry-type transformer winding temperature monitoring and forced cooling fan activation at industrial substations serving SABIC petrochemical complexes, where the 3RS triggers fan start 10°C below the trip setpoint to prevent unnecessary transformer shutdown.
- Motor bearing temperature monitoring at MARAFIQ utility pump stations in Jubail and Yanbu, where the 3RS Pt100 inputs monitor both drive-end and non-drive-end bearing temperatures for predictive maintenance scheduling.
- Kiln drive motor thermal protection at Saudi Cement and YACCO cement plants, where the harsh dusty environment and high ambient temperatures require sensitive thermal monitoring beyond the capability of bimetal overload relays.
- Generator winding temperature monitoring at SEC embedded generation facilities, where the 3RS provides the IEC 60034-1 Class F insulation protection required for generator warranty compliance and insurance certification.
- Cooling system pump and fan motor protection in pharmaceutical and food processing facilities, where motor overtemperature alarms are integrated into the SCADA system via the relay's auxiliary contact output.
- Process furnace temperature monitoring at petrochemical catalyst regeneration and cement kiln facilities, where thermocouple type K inputs monitor reactor tube skin temperatures for process safety management.
Industrial Supplier in Saudi Arabia
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Frequently Asked Questions — 3RS1040-1GD50
Common questions from buyers in Saudi Arabia and the GCC