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To ensure accuracy, please note that images may be representative. Refer to the product data sheet for detailed specifications.
| Manufacturer | SSAC / Littelfuse |
| Manufacturer Product Number | DLMUBRAAA |
| Description | Phase Monitor Relay; Lo/Hi V, Unbal, Loss, Rev; 3; 200...480V AC |
| Datasheet | Download Datasheet |
The Littelfuse SSAC DLMUBRAAA is a universal 3-phase voltage monitor for 200-480 V AC systems. It protects against phase loss and reversal, over- and undervoltage, voltage unbalance and over/under frequency, measuring each phase with microcontroller accuracy.
Trip points: high voltage 109-113% of the adjusted line voltage; low voltage 88-92% of the adjusted line voltage; unbalance 2-10% adjustable; phase loss at 25% or more. Trip delay: 1-30 s adjustable. Restart delay: 0.6-300 s adjustable, staggered restart. Output: SPDT 10 A resistive at 240 V AC, 8 A at 277 V AC, NO 1/4 hp at 120 V AC, 1/3 hp at 240 V AC; alarm NO 2 A at 277 V AC (isolated). Contacts: 1 Form C (SPDT) + 1 Form A (NO alarm). Indicator: LED diagnostics. Approvals: ASME A17.1 rule 210.6; NEMA MG1 14:30, 14:35.
Mounting: DIN Rail or Surface Mount. It operates from -40 to +60 °C and stores from -40 to +85 °C.
| Category | |
| Manufacturer | SSAC / Littelfuse |
| Model | DLMU |
| Monitoring Function | Low voltage, high voltage, voltage unbalance, phase loss, phase reversal, over/under frequency |
| Number of Phases | 3 |
| Sensing Method | Three-phase delta or wye, no neutral connection; universal line voltage, frequency auto-detected |
| Input Voltage | 200...480V AC |
| Input Operating Range | 50/60 Hz, auto-detected |
| Undervoltage Trip Range | 88-92% of the adjusted line voltage |
| Overvoltage Trip | 109-113% of the adjusted line voltage |
| Phase Unbalance Trip | 2-10% adjustable; phase loss at 25% or more |
| Restart Delay (s) | 0.6-300 s adjustable, staggered restart |
| Trip Delay - Phase Loss and Reversal (ms) | 200 ms |
| Trip Delay - Unbalance | 1-30 s adjustable |
| Reset Method | Automatic |
| Status Indicator | LED diagnostics |
| Contact Configuration | 1 Form C (SPDT) + 1 Form A (NO alarm) |
| Output Rating | SPDT 10 A resistive at 240 V AC, 8 A at 277 V AC, NO 1/4 hp at 120 V AC, 1/3 hp at 240 V AC; alarm NO 2 A at 277 V AC (isolated) |
| Number of Poles | 2 |
| Mounting Type | DIN Rail or Surface Mount |
| Operating Temperature (Storage) | -40...+60 °C (-40...+85 °C) |
| Approvals | ASME A17.1 rule 210.6; NEMA MG1 14:30, 14:35 |