Alternator Brands Compared

In a generator set, the engine produces mechanical power and the alternator converts this power into electricity. Voltage stability, the starting of large motors and operation with loads that generate harmonics depend largely on the alternator. In our sets we use Stamford, Mecc Alte and Leroy-Somer alternators, as well as TA-series alternators (model codes TA…, e.g. TA160-10N2). In this article we compare these options impartially. The power ranges and engine pairings are taken from our own product data; for the technical values of the alternators, the data sheet of each model should be used as the reference.

Brands and power ranges in our line-up

Alternator brand	Origin	Set power in our line-up (standby)	Series in the catalogue
Stamford	United Kingdom	10–4,125 kVA	S0–S7, UC series
Mecc Alte	Italy	10–4,125 kVA	ECO, ECP series
Leroy-Somer	France	10–2,750 kVA	TAL, LSA series
TA series	—	10–4,125 kVA	TA160-10N2, TA180-34N2, TA315-300N …

Stamford. An alternator brand of UK origin. In our line-up it is offered on sets with Perkins, Cummins, Baudouin, FPT Iveco, Scania and Volvo Penta engines.

Mecc Alte. An Italy-based alternator manufacturer. It is offered with the same engine brands and in the same power range as Stamford.

Leroy-Somer. An alternator manufacturer of French origin and part of the Nidec group. In our line-up it is offered on sets with Perkins, Cummins and FPT Iveco engines, up to 2,750 kVA.

TA series. Alternators with TA model codes (e.g. TA160-10N2, TA180-34N2, TA315-300N) are offered with all twelve engine brands in our line-up. On sets with Kofo, Kubota, Quartz, SDEC, Yangdong and Yuchai engines, the TA series is the standard alternator option.

Engine and alternator pairings

Engine brand	Stamford	Mecc Alte	Leroy-Somer	TA series
Perkins	✓	✓	✓	✓
Cummins	✓	✓	✓	✓
FPT Iveco	✓	✓	✓	✓
Baudouin	✓	✓	—	✓
Scania	✓	✓	—	✓
Volvo Penta	✓	✓	—	✓
Kofo	—	—	—	✓
Kubota	—	—	—	✓
Quartz	—	—	—	✓
SDEC	—	—	—	✓
Yangdong	—	—	—	✓
Yuchai	—	—	—	✓

For a comparison of engine brands, see our article on generator engine brands.

Common features

Regardless of brand, the alternators in our catalogue are listed with IP23 protection and class H insulation. Most models are self-excited and regulate the voltage with an AVR (automatic voltage regulator); PMG excitation is offered on some models. For dusty, humid or salty environments, options such as higher protection, anti-condensation heaters and winding protection are assessed according to the project.

Values to check when comparing

A brand comparison should be made using the data sheets of models of the same power. The main values to check are:

• Rated power and temperature rise: The alternator’s kVA rating is given for a specific ambient temperature and winding temperature rise class. The set’s power and the alternator’s power should be compared under the same conditions.
• Motor starting capacity: The voltage dip that occurs when large motors start is related to the alternator’s starting kVA. It is decisive for loads such as pumps and compressors.
• Harmonics: If loads such as frequency drives, UPS and rectifiers make up a large share, the alternator can be chosen one size up. For sets running in parallel, the winding pitch (for example 2/3) is also taken into account.
• Voltage regulation and AVR: The voltage accuracy of the AVR and the availability of a spare AVR in the region are important.
• Efficiency: On sets that run for long hours, a small difference in alternator efficiency is reflected in fuel consumption.
• Connection flexibility: 12-lead alternators can be reconnected for different voltages. For details on changing frequency and voltage, see our article on the difference between 50 Hz and 60 Hz.

How to choose

• If the specification names an alternator brand, the choice is made with the appropriate model of that brand.
• If there is no specification, the engine brand and power are decided first, then the alternator options offered with that engine are compared.
• If there are harmonic loads and large motor starts, the alternator is sized according to the load list.
• Access to spare parts and service in the region where the site is located is assessed.

For sets that will run synchronised, the alternator choice is considered together with the conditions of parallel operation; we cover this topic in our article on synchronised operation of generators.

Next step

If you share your load list, we will determine the engine and alternator combination together based on the data sheets. You can estimate the power with the power calculator, and for your project, contact us.