siemens
Siemens SIRIUS 3UG Voltage & Phase Monitoring Relay
Model: 3UG4622-1AW30
4-hour response · Pricing in SAR · Delivery across all KSA regions
3UG4622-1AW30 — Siemens SIRIUS 3UG Voltage & Phase Monitoring Relay
The Siemens SIRIUS 3UG voltage and phase monitoring relay is the standard protective relay for three-phase supply quality monitoring in Saudi Arabia's industrial control panels — the low-cost, always-on watchdog that detects the most damaging supply abnormalities before motors fail. The 3UG simultaneously detects all five common three-phase supply fault conditions: complete phase failure, incorrect phase sequence, phase voltage asymmetry above 10%, phase overvoltage above the set threshold, and phase undervoltage below the set threshold. A single 3UG relay wired to the three-phase supply bus monitors all five conditions for every connected motor and piece of equipment — replacing five separate monitoring relays or a dedicated power quality analyser.
Phase failure and phase reversal protection are the 3UG's most critical functions in Saudi industrial applications. Phase failure (single-phasing) is one of the most frequent causes of motor burnout in the Kingdom — a blown supply fuse or loose terminal leaves a three-phase motor running on two phases, causing it to draw approximately 1.73× full-load current on the remaining phases and overheat to failure within minutes if thermal protection does not trip. The 3UG's phase failure detection trips within 2–4 seconds of single-phasing, acting as a final protection layer before the thermal overload relay accumulates sufficient heat to trip. Phase reversal detection prevents reversed motor rotation after maintenance reconnection work on Saudi industrial sites where connection errors would cause pump reversal before operators notice the flow direction problem.
The 3UG mounts on standard 22.5 mm DIN rail and connects directly to the three-phase supply to be monitored without CT or VT inputs, making installation as simple as connecting the supply and setting two adjustment pots for overvoltage and undervoltage thresholds. The single changeover output contact (5 A, 250 V AC) trips the motor starter's control circuit or activates an alarm when any monitored condition is detected.
Razz Middle East stocks 3UG monitoring relays in 200–480 V three-phase variants for immediate delivery throughout Saudi Arabia.
Technical Specifications
Full specifications for the 3UG4622-1AW30
- Monitoring
- Phase failure, phase sequence, asymmetry (>10%), overvoltage, undervoltage
- Voltage
- 200–480 V AC (3-phase direct connection)
- Response Time
- 2–20 s (adjustable)
- Trip Thresholds
- Overvoltage and undervoltage adjustable by pot
- Output
- 1 changeover contact (5 A, 250 V AC)
- Mounting
- DIN rail 22.5 mm
- Supply
- Measured from monitored circuit
- Standard
- IEC 60255
Key Features & Benefits
- Five-function protection in one device — phase failure, sequence, asymmetry, overvoltage, undervoltage — replaces five separate monitoring relays with a single 22.5 mm DIN-rail device, reducing panel space and wiring.
- Phase failure detection within 2–4 seconds of single-phasing provides a critical final protection layer before the thermal overload relay trips, preventing motor burnout in the most common supply-side failure mode.
- Phase reversal detection prevents damage from reversed motor rotation after maintenance reconnection or transformer replacement, catching connection errors before pumps run backwards.
- Direct three-phase supply connection — no CT or VT required — makes installation as simple as connecting supply wires and adjusting two threshold pots, achievable by any qualified electrician.
- Adjustable response time (2–20 seconds) prevents nuisance tripping during momentary supply disturbances such as motor starting voltage dips while still protecting against sustained phase failure.
- Asymmetry detection at >10% phase voltage imbalance identifies deteriorating supply conditions before imbalance causes excessive negative-sequence heating in motors.
- Single changeover output contact rated 5 A, 250 V AC directly interrupts the motor starter's control circuit or activates an alarm without additional interface relays.
Industrial Applications in Saudi Arabia
- Three-phase motor protection in industrial motor starter panels across ARAMCO, SABIC, and NWC facilities, providing supply quality protection in addition to the thermal overload relay's load-current protection.
- Pump motor protection in water booster stations and irrigation pump panels, where phase failure detection prevents undetected single-phasing at unmanned remote pump stations.
- HVAC chiller and air handling unit motor protection in commercial buildings, where phase reversal detection catches reconnection errors after equipment maintenance.
- Industrial compressor motor protection at manufacturing facilities, where asymmetry detection identifies deteriorating supply quality before motor insulation damage accumulates.
- Generator output monitoring in standby power systems, where the 3UG verifies generator output voltage, phase sequence, and balance before the transfer switch connects the generator to the critical load bus.
- Supply quality monitoring at oil field pump station motor control panels in remote desert locations, where simple two-pot commissioning allows field technicians to set up monitoring without specialist equipment.
- Transformer secondary supply monitoring in industrial substation distribution boards, where asymmetry detection identifies unequal single-phase loading causing transformer neutral current and overheating.
Industrial Supplier in Saudi Arabia
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Frequently Asked Questions — 3UG4622-1AW30
Common questions from buyers in Saudi Arabia and the GCC