Cummins C275D5 275 kVA Diesel Generator Set

Overview

The Cummins C275D5 is a 50 Hz Cummins Power Generation diesel genset rated at 275 kVA (220 kW) standby and 250 kVA (200 kW) prime. It is one of the most frequently specified sizes in the Middle East, because a 250 to 275 kVA set covers the full building load of many villas compounds, shopping centres, hospitals wings and light industrial units. Cummins builds it on the QSL9-G5 engine, an electronically controlled 8.8 litre six-cylinder, and offers it open or in a sound attenuated, weather protective housing for Africa and the Middle East, Asia Pacific, Europe, India and Latin America.

Seven Star LLC supplies the Cummins C275D5 for projects in Muscat, Sohar, Salalah, Duqm and across the GCC. Our engineers help consultants and contractors define voltage, enclosure and control options, and compile the Cummins engine data and rating card needed for approval.

Operating Principle

Unlike the mechanically injected B-Series sets, the QSL9-G5 engine uses Bosch high pressure common rail (HPCR) fuel injection under full-authority electronic control. Fuel is stored at high pressure in a shared rail, and the engine control module decides the exact timing and quantity of each injection. Centred injectors in a 24-valve head, with four valves per cylinder, give efficient combustion, while the Holset HX40 wastegated turbocharger is designed to optimise transient response when a large motor or a block of load is switched on.

The engine drives a Stamford UCDI274K alternator at 1500 rpm to produce 50 Hz power, and the PowerCommand 1.2 control supervises starting, protection and metering. Cummins states that the QSL delivers up to 50 percent torque rise, better fuel economy and better cold starting than its predecessors, and is up to 50 percent quieter in operation, which is helpful for sets installed close to residential areas.

Engineering Design of the Cummins C275D5

The QSL9-G5 is a four-cycle, in-line six-cylinder engine with a 114 mm bore, 145 mm stroke and 8.8 litre displacement. An integrated block design routes coolant and oil through internal passages instead of hoses, which removes common leak points. The engine is supplied as a G-Drive Coolpac with air-to-air charge cooling, a 36 litre coolant system, a 26.5 litre lube oil capacity and a 24 V starting system with a 70 A charging alternator.

Cummins rates the Coolpac for a limiting ambient of 50 °C at 50 Hz. The engine is listed as TA Luft compliant and is built in ISO 9001 certified facilities. On the rating card, the Cummins C275D5 uses the PowerCommand 1.2 controller, while emission-certified variants such as the C275D5e use the QSL9-G7 engine instead, so buyers should confirm which version fits their permit requirements.

Key Features

The main reasons engineers specify the Cummins C275D5 for medium-size standby and prime duty are listed here.

• Rated 275 kVA standby and 250 kVA prime at 50 Hz according to Cummins.
• QSL9-G5 engine with Bosch HPCR common rail fuel injection and full-authority electronic controls for precise fuelling and diagnostics.
• Holset HX40 wastegated turbocharger tuned for fast transient response to load steps.
• 24-valve cylinder head with centred injectors for efficient, quieter combustion.
• Integrated block design that replaces external hoses with internal fluid circuits.
• Air-to-air charge cooled Coolpac with a 50 °C limiting ambient rating.
• Stamford UCDI274K alternator and PowerCommand 1.2 control as standard.
• Engine fuel use of about 63 L/h at full prime load, falling to 31 L/h at 50 percent load.

Industrial Applications

Across Oman the Cummins C275D5 protects hospitals, government buildings, malls, hotels and data rooms, and it is a popular prime power set for desalination pre-treatment skids, quarry crushers and labour camps. Its electronic engine gives the steadier frequency that UPS systems and variable speed drives prefer, which makes it suitable for pumping stations in water networks and for district cooling auxiliaries in Muscat developments.

In the oil and gas sector, contractors deploy sets of this rating for rig camps, workshops and temporary process power around fields in the interior. When a project needs a matching-size alternative with the same engine family, the Cummins 312/315 kVA diesel generator set is closely related. Remote monitoring can be added with a DSE7320 auto mains failure controller. Seven Star LLC supplies the Cummins C275D5 across Oman and the GCC and supports buyers through sizing and submittals.

Technical Specifications

Values for the Cummins C275D5 below come from the Cummins product page, the 2025 Europe 50 Hz rating card and the QSL9-G5 engine specification sheet.

Sizing Notes for the Cummins C275D5

Many buyers compare the Cummins C275D5 with the C300D5 and C330D5, which use the same QSL9-G5 engine at higher outputs. The right choice depends on the largest motor starting step and the expected average load: a lightly loaded large set wastes fuel and can suffer from wet stacking, while an undersized set may trip during motor starts. Our team reviews the load list with you and recommends the rating that keeps the engine working in its efficient range.

How to Order

Send Seven Star LLC your RFQ for the Cummins C275D5 with the voltage, standby or prime duty, enclosure and any noise limits. Our Muscat office will confirm the build with Cummins, advise on delivery time and provide the QSL9-G5 engine specification sheet and rating card. Contact our power generation team for a quotation anywhere in Oman and the GCC.