Generac · SD/MD Series (Industrial Diesel)

Generac SD900/MD900

900 kW standby · Diesel · Liquid-cooled

900 kW diesel industrial standby generator. Perkins 30.6L inline-8 turbocharged/aftercooled, EPA Tier 2 Certified Stationary Emergency.

Generac Generac SD900/MD900 generator — specifications and details
Standby power
900 kW
Voltage options
277/480V, 346/600V
Frequency / Phase
60 Hz · 3-phase
Engine
Perkins 30.6L · 30.6L
EPA / Emissions
Tier 2
Alternator
Generac
CommercialManufacturingHealthcareData Centers
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Overview#

The Generac SD900/MD900 is a 900-kilowatt industrial diesel generator powered by a Perkins 30.6-liter inline-8 turbocharged and aftercooled diesel engine. This unit is EPA Tier 2 Certified for Stationary Emergency applications and is designed for mission-critical standby power. The SD and MD designations represent different enclosure and configuration options on the same power platform. Generac also offers this model as part of its Modular Power Systems (MPS) lineup for paralleled multi-megawatt installations.

Our Service Experience#

The SDMD900 occupies a practical middle ground in Generac's industrial diesel lineup -- large enough for substantial facility backup but more manageable than the 1500+ kW V16-powered units for installation and ongoing service. The Perkins 30.6L inline-8 engine has a strong service track record. As with all standby generators, fuel quality management is critical -- units that sit for extended periods between exercises benefit from fuel polishing systems and regular fuel quality testing.

Engineering specifications

Fuel system & runtime

Fuel use @ full load
63 GPH
Fuel use @ 75% load
47.3 GPH
Fuel use @ 50% load
33.8 GPH

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Estimate runtime for the Generac SD900/MD900

Adjust load percent and tank size to estimate runtime. Pre-filled with this model's spec where available.

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Estimated runtime

4.1 hours(0.2 days)

Fuel consumption ≈ 48.60 GPH at 75% load. Estimate based on industry-typical 1800 RPM standby curves (≈0.07 GPH/kW at full load). Actual consumption varies by engine, ambient temperature, fuel quality, and tuning.

Service intervals

Manufacturer-recommended intervals for the Generac SD900/MD900 under standby duty. Field intervals may differ based on load profile, ambient conditions, and fuel quality.

Oil & filter
Every 500 hours or 12 months
Coolant change
Every 4000 hours
Air filter
Every 1000 hours
Fuel filter
Every 500 hours
Load bank test
Every 12 months

Common failure modes

What we've seen fail on this platform. Use as a service-planning reference, not a diagnostic — actual failure modes depend heavily on duty cycle and maintenance history.

ComponentSymptomTypical hoursSeverity
Fuel quality / degradationHard starting, injector fouling, filter clogging, reduced power output4,380+moderate
TurbochargerPower loss, excessive smoke under load, oil consumption15,000+moderate
High pressure common rail injection systemRough running, misfiring cylinders, fuel rail pressure faults20,000+severe
Battery (24 VDC system)Failed to start, slow cranking8,760+minor

Frequently Asked Questions

What engine does the Generac SDMD900 use?
The current SDMD900 uses a Perkins 30.6-liter inline-8 turbocharged and aftercooled diesel engine running at 1800 RPM. The engine features a bore of 6.3 inches (160 mm), stroke of 7.48 inches (190 mm), and 14.1:1 compression ratio. It produces approximately 1,389 horsepower at standby rating and is EPA Tier 2 Certified for Stationary Emergency applications. An earlier version used a 37.1L Mitsubishi V12 engine.
What is the fuel consumption of the Generac SDMD900?
At standby rating on ultra-low-sulfur diesel, the SDMD900 consumes approximately 63 gallons per hour at 100% load, 47.3 gph at 75% load, and 33.8 gph at 50% load. Actual consumption varies by site conditions, load profile, and altitude.
What voltages are available for the SDMD900?
The SDMD900 is available in two three-phase configurations: 277/480 VAC and 346/600 VAC, both at 0.8 power factor. The generator meets UL 2200 standards and supports paralleling through Generac's Modular Power Systems (MPS) platform.

Compatible equipment

Transfer switches

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