Open Generator Sets

An open generator set is a generator set in which the diesel engine, alternator, control panel and fuel tank are mounted on a common steel base frame without a canopy. It is also known as an “open-type generator”. Sound insulation and weather protection are not part of the set itself but of the place where it is installed: a generator room, a roofed shelter or a project-specific enclosure.

Terex Diesel has been in the generator industry since 2006. We build our open sets at our production facility in Türkiye and test every set at full load before delivery. On this page you will find how an open set is built, where it is used, what a generator room needs and our open-type models by power.

What is an open generator set?

The open set is the most basic and most compact form of a generator. Without a canopy, all parts are visible and accessible. An open set consists of the following main parts:

• Diesel engine and alternator: Mounted on a common base frame with anti-vibration mounts.
• Radiator and fan: The engine cooling system, aligned with the air outlet of the room.
• Control panel: As standard, sets below 500 kVA use the Datakom DKG-309 controller and sets of 500 kVA and above use the Datakom D-500 controller.
• Base-frame fuel tank: The tank capacity depends on the model. In installations that need a long running time, the set can be connected to an external fuel tank.
• Exhaust outlet: The silencer and exhaust line are designed for the place where the set will be installed.

Where is an open set used?

An open set is used where the set is already protected from the weather and unauthorised access:

• Generator room: A technical room inside the building of a hospital, office building, hotel, data centre or industrial plant. This is the most common use.
• Shelter or plant building: Roofed areas with protected sides and ventilation, common in agriculture, irrigation and industry.
• Project-specific enclosure: Applications where the set is built into a special canopy, a container or a vehicle. The open set is the basis of these solutions.
• Parallel systems: Installations where several sets run synchronised in the same room; see synchronization panels.

An open set should not be placed directly outdoors, as it is not protected against rain, dust or unauthorised access. For outdoor use, choose canopied generator sets.

Generator room requirements

Whether an open set runs correctly depends largely on how the room is prepared. The main points are:

• Air inlet and outlet: There must be enough fresh air for the engine’s combustion air and the radiator’s cooling air. The air heated by the radiator should be ducted straight outside and must not return into the room.
• Exhaust line: The exhaust gas must be led out of the building through a tight line and a silencer, away from areas where people are present and away from air inlets.
• Base: The set should stand on a level concrete plinth that can carry its weight, with anti-vibration mounts so that vibration is not transferred to the building.
• Fuel: Day tank and external tank connections, the fuel line and spill protection should be planned.
• Maintenance space: Enough clearance should be left around the set for maintenance.
• Noise: The noise of an open set is controlled by the insulation of the room. In buildings with a noise limit, attenuating louvres are added to the air inlets and outlets.

We cover these points in more detail in our article on generator rooms and installation. For room preparation and set selection you can use our site survey and power assessment service.

Open, canopied and containerised sets compared

	Open set	Canopied set	Containerised set
Installation	Generator room, shelter or project-specific enclosure	Outdoors; no separate room needed	Outdoors; high-power installations
Power range (Terex)	10–2,750 kVA	From the smallest set up to 1,100 kVA	Above 1,100 kVA
Sound insulation	None; depends on the room insulation	By the canopy; series figure ±75 dB(A) @7 m	By the container insulation
Weather protection	Building or enclosure protects	Canopy protects	Container protects
Footprint	Smallest	Larger because of the canopy	Largest
Installation work	Room ventilation, exhaust line, fuel line	Base, cabling and exhaust direction	Base, cabling, crane positioning
Maintenance access	Open from all sides	Through the canopy doors	From inside the container

In short: if a generator room or a protected area is available, an open set is the most compact and usually the most economical solution. Without a room, a canopied set is used, and at very high ratings a containerised generator.

Power range and engine options

Our open sets cover ratings from 10 kVA to 2,750 kVA; models with higher ratings are supplied in a container. Engine options come from Perkins, Baudouin, Cummins, FPT Iveco, Kofo, Kubota, Quartz, Scania, SDEC, Volvo Penta, Yangdong and Yuchai. The table below shows the number of models in each power range, the engine brands and the open-set weight and tank values. Each row links to the power page that lists all models at that rating.

For high power needs, dual generator sets, with two sets running synchronised on one base frame, are another option.

Production and quality

Our sets are built in our 2,000 m² production area in Türkiye and every set is tested at full load before delivery. Our production complies with ISO 9001, CE and TSE-HYB. For export shipments we provide the certificate of origin.

If your existing open set needs a canopy, see the generator canopies page. If you are not sure which rating you need, use the power calculator or fill in the form at the top of this page.