Generators and alternators: Equipment and suppliers

Rotors, stators and hydrogen cooling inside a turbo-generator

What this tab covers For each method, the main pieces of equipment, who makes them (by region) and what they are made of (bill of materials).

A large generator is a rotor, a stator, an exciter and a cooling system; gensets use a simpler air-cooled alternator.

Large turbo-generator

Stator¹²⁴⁵⁸⁹¹¹¹⁰

Fixed outer part holding the three-phase windings in which voltage is induced.

United States GE Vernova Europe Siemens Energy, Arabelle Solutions Japan and Korea Toshiba China Dongfang Electric, Harbin Electric, Shanghai Electric India Bharat Heavy Electricals

Bill of materials

Windings: copper bars, hollow for water cooling in the largest units, with stainless steel water boxes
Core: stacked thin laminations of electrical steel to limit eddy currents
Insulation: mica-based insulation systems

Rotor and exciter¹²⁴⁸

Spinning electromagnet fed with DC from the exciter; carries the magnetic field.

United States GE Vernova Europe Siemens Energy, Arabelle Solutions China Harbin Electric (with BEST generators), Dongfang Electric

Bill of materials

Rotor body: single large alloy-steel forging
Field winding: copper

Cooling system¹²³

Removes about 1% of throughput as heat.

United States GE Vernova Europe Siemens Energy (water-cooled stator with pressurised air, SGen-2000P), Arabelle Solutions

Bill of materials

Coolant: air (to about 400 MVA), hydrogen gas, demineralised water

Genset alternator

Brushless alternator⁶¹²¹³¹⁴

Air-cooled synchronous machine driven directly by a diesel or gas engine.

United States Caterpillar, Cummins, Generac, Rehlko (formerly Kohler Energy) Europe Rolls-Royce Power Systems (mtu), Volvo Penta

Bill of materials

Stator and rotor: copper windings in electrical steel

Wind generators

Permanent-magnet or induction generator³¹⁵

Converts slow or variable rotor speed into electricity via a converter.

Europe Siemens Energy

Bill of materials

Magnets: neodymium-iron-boron magnets (about 28.5% neodymium, 4.4% dysprosium, 1% boron, 66% iron by mass); up to 4 tonnes per turbine; at 180 kg Nd per MW this is roughly 630 kg of magnet per MW (calculated)
Windings and core: copper and electrical steel

Sources

GIGATOP generators Arabelle Solutions, 2025
Air-cooled generators (GEN-A) GE Vernova, 2025
Generators for power generation (product overview and references) Siemens Energy, 2025
Harbin Electric wins bids for two 2 GW coal-fired power projects in China Enerdata, 2024
GE HA Turbine Snags Another World Record for CCGT Efficiency POWER Magazine, 2018
Engine Power Plants Surge as Data Centers Drive Unprecedented Demand POWER Magazine, 2026
Dongfang Electric Corporation Limited: Annual results announcement for the year 2025 Dongfang Electric (HKEX filing), 2026
Harbin Electric Company Limited: Annual results announcement for the year ended 31 December 2025 Harbin Electric (HKEX filing), 2026
BHEL: order for 1x800 MW Anuppur thermal power project (stock exchange disclosure) Bharat Heavy Electricals Ltd (NSE filing), 2025
Shanghai Electric Power Generation Group (company profile) Shanghai Electric, 2025
Generac reports fourth quarter and full-year 2025 results Generac Holdings, 2026
Kohler Energy changes name to Rehlko Equipment World, 2024
Cummins Inc. Form 10-K for fiscal year 2025 Cummins / US SEC, 2026
The role of rare earth elements in wind energy and electric mobility (Alves Dias, Bobba, Carrara, Plazzotta), EUR 30488 EN European Commission Joint Research Centre, 2020