Overview#
The Generac SD275 is a 275-kilowatt industrial diesel standby generator powered by an Iveco/FPT 10.3-liter turbocharged and aftercooled inline-six engine. Rated at 275 kW standby and 248 kW prime (344/309 kVA), the SD275 uses Generac's largest standard displacement engine in this range: a 10.3L platform with common rail injection, 4-valve cylinder heads, and a 31.68-quart crankcase. BMEP is 308 psi, exhaust temperature is 950°F (510°C), and heat rejection to coolant is 722,612 BTU/hr. The generator is EPA Certified for Stationary Emergency applications.
Generac pairs the Iveco 10.3L with the K0275124Y21 alternator featuring Class H insulation, Permanent Magnet excitation, and a 24-VDC electrical system with dual 12V batteries. The Digital H control panel provides NFPA 110 Level I and II programmable operation, Modbus communications, and 16-channel remote trending. The engine coolant heater and closed coolant recovery system are standard.
At 275 kW, this unit serves large commercial and industrial standby applications: large hospital campuses with multiple life-safety circuits, large data centers, industrial facilities with significant motor loads and process equipment, large multi-tenant office buildings, and applications where a single larger generator consolidates what would otherwise require multiple smaller units. The 14,505 cfm ventilation air requirement demands careful enclosure design for enclosed installations.
Technical Specifications#
| Parameter | Value |
|---|---|
| Standby Rating | 275 kW / 344 kVA |
| Prime Rating | 248 kW / 309 kVA |
| Engine Make | Iveco/FPT |
| Displacement | 10.3 L (628.5 in³) |
| Cylinders | 6, In-Line |
| Bore x Stroke | 4.92 x 5.51 in (125 x 140 mm) |
| Compression Ratio | 16.5:1 |
| Aspiration | Turbocharged/Aftercooled |
| Fuel Injection | Common Rail |
| Engine Speed | 1,800 RPM |
| Alternator Model | K0275124Y21 |
| Insulation Class | H |
| Fuel Type | Ultra Low Sulfur Diesel #2 |
| Fuel Consumption (100%) | 19.6 gph |
| Fuel Consumption (75%) | 15.8 gph |
| Fuel Consumption (50%) | 11.7 gph |
| Fuel Consumption (25%) | 6.8 gph |
| Exhaust Flow | 2,050 cfm at rated output |
| Exhaust Temperature | 950°F (510°C) |
| Heat Rejection to Coolant | 722,612 BTU/hr |
| Combustion Air | 780 cfm |
| Ventilation Air | 14,505 cfm |
| Open Set (no tank) L x W x H | 137.5 x 57.6 x 67.8 in |
| Open Set Dry Weight | 6,121 -- 7,457 lbs |
| Max Ambient Temperature | 110°F (43.3°C) |
Our Service Experience#
The SD275 is one of the larger units in our service territory. At this power level, the economics of professional preventive maintenance are clear: an unplanned failure at 275 kW affects facility operations at a scale that justifies quarterly fuel sampling, annual load bank testing, and dedicated service contracts.
The 14,505 cfm ventilation air requirement is the largest specification item to verify at installation. Enclosed SD275 installations with inadequate air management develop overheating problems that present first as nuisance alarms before leading to hard failures. Verify the enclosure ventilation design matches the spec sheet requirements.
The dual 12V battery system (24 VDC) should be treated as a matched pair and replaced together at the same service interval. Unequal battery aging causes uneven charge/discharge cycles and reduces system reliability.
Frequently Asked Questions#
Why is the maximum operating temperature lower for the SD275 (110°F) versus smaller SD models (122°F)? The SD275's maximum ambient temperature before derate is 110°F (43.3°C) versus 122°F (50°C) for smaller models. This reflects the higher heat load of the 10.3L engine at 275 kW -- the cooling system is sized for the nominal operating range, and derate begins at a lower ambient threshold. In hot climates or enclosed installations with elevated ambient temperatures, confirm derating with a Generac industrial dealer.
How does the SD275 compare to the SD250? The SD275 uses the Iveco/FPT 10.3L versus the 8.7L in the SD250. The SD275 provides 10% more standby capacity (275 vs 250 kW), has significantly more exhaust flow (2050 vs 1550 cfm), higher heat rejection (722,612 vs 682,058 BTU/hr), and weighs approximately 40% more (6121 lbs vs 4325 lbs open set). The SD275 also requires substantially more ventilation air (14,505 vs 8,872 cfm). For applications where 250 kW is sufficient, the SD250 is more compact and easier to site.
What fuel tank runtime does the SD275 provide? At 19.6 gph full standby load: 183-gallon tank provides approximately 9 hours, 438-gallon tank provides approximately 22 hours, 693-gallon tank provides approximately 35 hours, and 1325-gallon tank provides approximately 67 hours. The 1325-gallon tank meets most NFPA 110 Class 48 requirements but may fall slightly short of Class 72 at full load -- verify with the project electrical engineer.
