Cummins QSK50 / KTA50-G9

1,250-1,500 kW standby diesel gensets on the Cummins 50 L V-16, from KTA50 workhorse to QSK50 Tier 4

Cummins QSK50 / KTA50-G9 is one of 10 data center generators tracked in the SecondWatt catalogue, each with specifications, lead times and indicative secondary-market pricing.

Cummins QSK50 and KTA50-G9 genset dossier: 1,250-1,500 kW ratings, verified specs, used pricing from 129,500 USD, and buyer inspection checklist.

Why it matters

The KTA50/QSK50 node is the value play of the 1.5 MW class: observed low-hour asks run roughly 60% below comparable CAT 3512C money. Hours since documented overhaul is the primary value driver per dealer guides, and Cummins Power Systems' record 2025-2026 results confirm the demand backdrop that keeps absorbing this supply.

Who buys it

Hospitals, mid-size data rooms, industrial plants, and export or rental buyers take the 1.5 MW Cummins node; KTA50s go to cost-focused and international buyers while Tier 2/Tier 4 QSK50s serve permit-sensitive US sites. The trigger is price and speed: sub-250-hour DFLE units at under 110 USD per kW ship in weeks against 52-70 week new-unit queues.

Role in the data center

Standby block at 1,250-1,500 kW behind the ATS for mid-size halls; KTA50 units also serve as low-cost bridge or temp power where permits allow.

Key specifications

Technical summary

DFLE genset (KTA50-G9): 1500 kW standby / 1250 kW prime DQGAB genset (QSK50): 1500 kW / 1875 kVA standby DQGAA genset (QSK50): 1250 kW standby Engine: 50.3 L V-16, 159 mm bore and stroke KTA50-G9 gross standby: 1655 kWm at 1800 rpm Fuel, KTA50-G9 standby 100%: 392 L/hr Fuel, prime 100/75/50/25%: 330 / 257 / 180 / 111 L/hr Voltages (DQGAB): 208-4160 V options DQGAB dimensions: 5969 x 2007 x 2840 mm DQGAB dry weight: 10989 kg Emissions: KTA50-G9 pre-tier; QSK50 Tier 2 and Tier 4F Controller: PowerCommand PCC 3201 (DQGAB)

Configurations and options

Used units appear open-skid, weatherproof, and sound-attenuated, mostly 277/480 V with PMG excitation. Options: PCC 3201 or later controls, 4,160 V alternators, jacket water heaters, and enclosures with sub-base tanks. Load-test documentation from dealer refurb programs adds resale value.

Compatibility and dependencies

Pairs with 1,875 kVA-class transfer gear and day tanks. KTA50 PT fuel systems need calibration at 6,000-hour service events and pre-tier status restricts new permits; QSK50 electronics integrate with PowerCommand paralleling. Parts flow through the worldwide Cummins distributor network.

Pricing and availability

Published price range: $129,500 – $159,900. Trend: up Dealer guide bands from 2026 put KTA50 sets at 75,000-220,000 USD, DQGAA 1,250 kW units at 140,000-260,000 USD, and DQGAB 1,500 kW units at 180,000-320,000 USD. Observed 2025-2026 DFLE asks of 129,500-159,900 USD for sub-250-hour units sit mid-band, with a 1984-vintage KTA-class unit clearing at 45,000 USD, showing how documentation and hours stratify the family. Lead time, new: 52-70 weeks. Lead time, used or refurbished: 2-8 weeks. Warranty, used: 30-day dealer typical; load-test certificates common.

Lifecycle and maintenance

KTA50 service cadence: oil, filters, and cooling inspection at 250 hours or 6 months; fuel filters, coolant flush, injector cleaning, and valve adjustment at 1,500 hours or annually; turbo inspection, ring work, PT pump calibration, and bearing checks at 6,000 hours or 2 years. A full major on a KTA50 is a planned event, and hours-since-major govern valuation per dealer guides. QSK50 electronics follow PowerCommand service tooling through Cummins distributors.

Common failure points

• Fuel filters and injectors — Power loss and rough running from clogged filters and deposits
• Water pump and heat exchanger — Corrosion-driven cooling loss
• Turbocharger — Shaft play and oil leaks by 6,000-hour service events
• Main and rod bearings — Wear signaled by oil analysis on high-hour units
• PT pump calibration (KTA50) — Cylinder power imbalance from calibration drift
• Ring and liner wear — Blow-by and oil consumption past major-interval hours

Inspection checklist

Generation check — confirm KTA50 (mechanical PT) versus QSK50 (electronic) on the dataplate; they price on different curves Hours — verify meter; observed DFLE bench runs 39-575 hours on 1999-2001 builds Overhaul documentation — hours since documented overhaul is the primary value driver; require records PT fuel pump (KTA50) — verify calibration at the 6,000-hour service event; drift causes power imbalance Injectors — clean and flow-test at 1,500-hour intervals per family schedule; verify compliance Turbochargers — inspect for shaft play and oil leaks; rebuild consideration at 6,000 hours Water pump and heat exchanger — inspect for corrosion, a documented KTA-family wear area Bearings — oil analysis for main and rod bearing wear; trend at least 2 samples Rings and liners — compression or blow-by test on units past 10,000 hours Generator end — megger stator; below 5 megohms warrants rewind pricing Controls — PCC generation and spares support; pre-PCC 3201 panels warrant budget Emissions posture — KTA50-G9 is pre-tier: confirm grandfathered siting or plan Tier 2/4 alternatives Coolant — verify 1,500-hour coolant service compliance and flush history Load test — 4-hour run to 100% of nameplate; dealer load-test certificates add value Records — complete service logs traceable to serial number; undocumented units price as cores

Regional notes

US dealer stock observed is entirely 60 Hz; 50 Hz KTA50/QSK50 units circulate in export markets. Pre-tier KTA50s flow toward international and grandfathered domestic sites, while Tier 2/4 QSK50s serve permit-constrained US installs.