Caterpillar 3512C prime mover

On an AC or mechanical land rig, the prime movers turn the generators that feed the drawworks, mud pumps, and top drive. The 3512C is Caterpillar’s V-12 diesel in the 3500 series, and it is one of the engines commonly bolted to those generators. NOV’s land-rig upgrade literature pairs a 3512C with an NOV generator as a genset.

It fits a rig whose generators, voltage, and rpm match this engine’s nameplate. Caterpillar publishes more than one rating for the 3512C family: continuous, prime, and standby, at more than one speed, including the 1,200 rpm used on many 60 Hz rigs. A standard-stroke 3512C and a higher-displacement HD are different engines that share the name. The kilowatts on the generator have to agree with the engine in front of it.

A Kato or other generator is the electrical half of the package. The 3512C is the diesel. A “1,265 kW generator” listing may be the machine this engine turns, and it may be a different frame entirely. Horsepower is not inside the characters 3512C. It is on the data plate, next to the rpm.

Read bhp or bkW, rpm, and whether the plate says HD. Ask for hours, overhaul records, and the emissions tier. Confirm the radiator or remote cooling is included, and that the generator, voltage, and frequency match. An engine without the generator it was aligned to is a rebuild project, not a drop-in genset.