Katolight Generators

Katolight Corporation built generator sets in Mankato, Minnesota from the 1960s through the mid-2000s, earning a reputation for rugged, no-frills industrial standby power at competitive prices. Founded in southern Minnesota — the name derives from "Mankato Light" — the company grew by serving customers who needed reliable backup power without the premium pricing of larger OEMs. Katolight manufactured both diesel and natural gas generator sets spanning 15 to 2,759 kW, covering everything from small commercial standby units to large industrial prime power systems.

The company's engineering strategy was straightforward: source best-in-class engines from John Deere, Cummins, and later MTU, package them with proven alternators and controls, and sell through a network of industrial distributors and dealers. This approach made Katolight particularly strong in agricultural, rural utility, and municipal power applications where equipment needed to run reliably in harsh conditions with minimal on-site technical support. Grain elevators, feed mills, irrigation systems, and rural hospitals across the Midwest were common Katolight installations — applications where the generator might sit dormant for months and then needed to start without hesitation when a storm knocked out grid power.

MTU (then part of DaimlerChrysler) acquired Katolight in 2006, primarily for its North American manufacturing capability, dealer network, and proven packager expertise. The Katolight brand was gradually absorbed into MTU Onsite Energy, which itself later became part of Rolls-Royce Power Systems. No new Katolight-branded generators have been manufactured since the mid-2010s, and production now continues under the MTU Onsite Energy name using the same Mankato facility. Despite the brand transition, the installed base of Katolight generators remains substantial, particularly in the 60-500 kW commercial and agricultural standby range where the units were most heavily sold.

For facility managers with existing Katolight generators, service and parts remain available through multiple channels. The Rolls-Royce Power Systems / MTU dealer network handles generator-specific controls, switchgear, and enclosure components. Engine parts come through the original engine manufacturer — John Deere, Cummins, or MTU — each of which maintains its own global parts and service network. The most commonly encountered Katolight models in the field pair John Deere 4045 (4.5L) and 6068 (6.8L) engines with standard industrial alternators, and parts for these engines are readily available worldwide through John Deere's extensive dealer network. Third-party aftermarket suppliers also stock common Katolight consumables and wear items, so owners are not solely dependent on OEM channels for routine maintenance.