How to read a generator datasheet: engine, alternator, controller and tank

A generator datasheet breaks down into four blocks: the engine (model, kWm, speed), the alternator (brand, model, voltage, frequency), the controller (start, monitoring, stop) and the enclosure with its tank (dimensions, weight, litres). Our 100 kVA set, for example, pairs a Perkins 1104C-44TAG2 engine with a Leroy-Somer TAL044D alternator and a Deep Sea DSE6010 controller.

What lines does a 100 kVA datasheet contain?

Here is the datasheet of our 100 kVA generator with a Perkins 1104C-44TAG2 engine, section by section. Values and units are as printed on the datasheet.

The datasheet gives a sound level for the soundproof version only. A sound level without its measuring distance cannot be compared.

What does the engine block tell you?

The engine block describes the machine that produces mechanical power. Its output is given in kWm: mechanical kilowatts measured at the shaft.

The 1104C-44TAG2 delivers 90 kWm. The generator set delivers 80 electrical kW at its prime rating. The gap is normal: the engine also drives the radiator fan, and the alternator has losses. So never compare a kWm figure with a kVA figure. Our kVA vs kW guide explains the conversion with the 0.8 power factor.

The 1,500 rpm speed follows from the frequency: a 4-pole alternator driven at 1,500 rpm produces 50 Hz, the grid frequency in the DRC.

What does the alternator block tell you?

The alternator turns the engine's rotation into electric current. The datasheet gives its brand, model, voltage, frequency and number of phases.

On our Perkins-engined sets, the alternator is a Leroy-Somer. The model changes with the rating: TAL044D at 100 kVA, TAL049E at 1,000 kVA.

The line "400/230 V or 380/220 V" reads as follows:

• 400 V or 380 V between two phases, for three-phase motors and equipment;
• 230 V or 220 V between one phase and neutral, for sockets and lighting;
• the dual rating (400/230 V) means a three-phase, four-wire output: three phases plus a neutral.

If you are unsure how many phases you need, read our single-phase or three-phase guide.

What does the controller do?

The controller is the electronic module on the control panel. In general, it starts and stops the set, displays its readings and triggers a protective shutdown on a fault.

The datasheet only gives the brand and model. To find out what it does, check its maker's documentation. According to Deep Sea Electronics' public documentation:

• the DSE6010 is an auto-start control module designed for a single generator set. It starts on command (button or remote start contact). It is fitted to every set in our 13 to 2,000 kVA range but one, including the 100 kVA;
• the DSE8610 is a synchronising and load-sharing module, designed for sites where several generators work together. It is fitted to our 1,000 kVA set with a 4008-TAG2A engine.

Detecting a mains failure and switching over automatically is, in Deep Sea's range, the job of an AMF module such as the DSE6020 or of an automatic transfer switch (ATS): ask how changeover is handled in your quote.

Both 1,000 kVA sets in our range use the same Leroy-Somer TAL049E alternator. The 1,000 kVA set with a 4008-30TAG2 engine uses a DSE6010. Beyond the engine model, it is the controller line that reveals the intended use: a single set or sets running in parallel.

Soundproof or open frame: which lines change?

The engine, alternator and controller stay the same. The dimensions (L, W, H), the weight and the tank change. Noise changes too: an open-frame set is much louder than a soundproof one. Our 100 kVA datasheet gives a sound level (75 dBA at 3 m) for the soundproof version only; for an open-frame set, ask for the figure and its measuring distance.

At 100 kVA, the soundproof version measures 275 × 110 × 142 cm and weighs 1,920 kg, with a 205 L tank. The open-frame version measures 210 × 76 × 140 cm and weighs 1,100 kg, with a 150 L tank. Read the values for the version you are buying. Our soundproof or open-frame guide lists these values from 13 to 1,000 kVA.

Small air-cooled sets have shorter datasheets, and their lines differ from one brand to the next:

When a line is missing, ask for it before you compare.

What are the common reading mistakes?

Three mix-ups come up again and again in quotes.

• Reading standby power as prime power. The 110 kVA standby figure is not a continuous-duty rating. Size on the 100 kVA prime rating. Our prime vs standby guide explains why. On small sets, read "maximum power" the same way: size on the rated power.
• Reading kWm as kWe (electrical kW). The engine's 90 kWm is not 90 kW available to your equipment. At its prime rating the set supplies 80 kW.
• Confusing tank size with run time. A tank is measured in litres, run time in hours. At full load, 205 L ÷ 22.6 L/h gives about 9 h. With the 150 L open-frame tank, about 6 h 40 min. At partial load, run time is longer: see our guide to fuel consumption in litres per hour.

What checklist should you use to compare two quotes?

Ask every supplier for the same lines, then compare them one by one.

1. Prime rating (PRP) in kVA and kW, with the standby rating (ESP) shown separately.
2. Engine brand and model, power in kWm, speed in rpm.
3. Alternator brand and model, voltage, frequency, number of phases.
4. Controller brand and model.
5. Version: soundproof or open frame.
6. Dimensions, weight and tank capacity of that version.
7. Fuel use in L/h at 100%, 75% and 50% load, and sound level with its measuring conditions (distance, version).
8. The full datasheet as a PDF.

Each generator product page links to its datasheet PDF. Our catalogues are gathered on the catalogues and datasheets page.

To compare every datasheet, browse our diesel generators from 13 to 2,000 kVA or use the generator finder.

For a quote, send us the rating you need or the model's datasheet on WhatsApp at +243 903 005 060. Prices are given on request. You can also use our contact page.

Frequently asked questions

What does kWm mean on a datasheet?

kWm is the engine's mechanical power, measured at the shaft. It is always higher than the set's electrical output. Our 100 kVA set has a 90 kWm engine for 80 electrical kW.

Why can two sets with the same rating have different controllers?

Because the controller depends on how the set will be used. According to Deep Sea Electronics, the DSE6010 runs a single set, while the DSE8610 is designed to synchronise several sets. Our two 1,000 kVA sets show the difference.

Is the datasheet enough to work out run time?

It gives the tank size and the full-load fuel use, which allows a worst-case estimate. Real run time depends on your load.

Sources: the generator-set datasheets published on our product pages (Perkins-engined sets, Bison and Brux sets); Deep Sea Electronics' public documentation (DSE6010, DSE6020 and DSE8610 modules).