Overview#
The Cat 3512 is Caterpillar's original megawatt-class V-12 diesel generator -- a 51.8-liter platform that has been a staple of large commercial and industrial power generation for decades. With ratings from 1000 to 1400 kVA and support for continuous, prime, standby, and mission critical duty cycles, the 3512 is one of the most versatile large diesel generator sets on the market.
The 3512 uses Direct Unit Injection with a Woodward 2301A isochronous governor, paired with Cat's EMCP 4.2 controller platform. The cooling system supports ambient temperatures up to 50 degrees C (122 degrees F), and optional high-ambient radiators are available. The generator features Class H insulation with random-wound or form-wound configurations.
The 3500 Series legacy#
The Cat 3500 Series engines have been in production since the 1970s and represent one of the longest-running large diesel engine platforms in the industry. The 3512 (V-12) and 3516 (V-16) share the same bore and stroke (170 x 190 mm) and many common components, which simplifies parts inventory for facilities operating both models.
Key specifications from the OEM spec sheet:
- Bore x stroke: 170 mm x 190 mm (6.69 in x 7.48 in)
- Displacement: 51.8 L (3,161 in3)
- Compression ratio: 13.5:1
- Exhaust flange: 203.2 mm (8.0 in)
- Starting system: 24V electric standard, dual starter optional
- Governor: Woodward 2301A isochronous
Our service experience#
The 3512 is a proven platform in Northern California's commercial and industrial market. The Woodward 2301A governor is extremely reliable but requires periodic calibration checks, especially on units that run infrequently. The 51.8L displacement means significant lube oil capacity -- oil sampling via Cat's S-O-S program is critical for trending wear metals. Fuel cooler maintenance is important on units with package-mounted radiators. The 3512's parts commonality with the 3516 makes it an efficient platform to support across a fleet.
