# Generators and alternators: Equipment and suppliers Rotors, stators and hydrogen cooling inside a turbo-generator Source page: https://www.materialinsights.org/energy/e_generators/equipment/ 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 **Stator**^[1](https://arabellesolutions.com/our-technology/generators-for-nuclear-power-plants/gigatop-generators)^[2](https://www.gevernova.com/gas-power/products/generators/air-cooled)^[4](https://www.enerdata.net/publications/daily-energy-news/harbin-electric-wins-bids-two-2-gw-coal-fired-power-projects-china.html)^[5](https://www.powermag.com/ge-ha-turbine-snags-another-world-record-for-ccgt-efficiency)^[8](https://www1.hkexnews.hk/listedco/listconews/sehk/2026/0331/2026033103547.pdf)^[9](https://www1.hkexnews.hk/listedco/listconews/sehk/2026/0326/2026032603158.pdf)^[11](https://www.shanghai-electric.com/group_en/dqdzjtwmdqy)^[10](https://nsearchives.nseindia.com/corporate/BHELCC_03092025171754_BHELOrderReceipt.pdf) 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 exciter**^[1](https://arabellesolutions.com/our-technology/generators-for-nuclear-power-plants/gigatop-generators)^[2](https://www.gevernova.com/gas-power/products/generators/air-cooled)^[4](https://www.enerdata.net/publications/daily-energy-news/harbin-electric-wins-bids-two-2-gw-coal-fired-power-projects-china.html)^[8](https://www1.hkexnews.hk/listedco/listconews/sehk/2026/0331/2026033103547.pdf) 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 system**^[1](https://arabellesolutions.com/our-technology/generators-for-nuclear-power-plants/gigatop-generators)^[2](https://www.gevernova.com/gas-power/products/generators/air-cooled)^[3](https://www.siemens-energy.com/global/en/offerings/power-generation/generators.html) 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 alternator**^[6](https://www.powermag.com/engine-power-plants-surge-as-data-centers-drive-unprecedented-demand/)^[12](https://investors.generac.com/news-releases/news-release-details/generac-reports-fourth-quarter-and-full-year-2025-results)^[13](https://www.equipmentworld.com/business/article/15704847/kohler-energy-changes-name-to-rehlko)^[14](https://www.sec.gov/Archives/edgar/data/26172/000002617226000009/cmi-20251231.htm) 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 generator**^[3](https://www.siemens-energy.com/global/en/offerings/power-generation/generators.html)^[15](https://www.apren.pt/contents/publicationsothers/eu--the-role-of-rare-earth-elements-in-wind-energy-and-electric-mobility.pdf) 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 1. [GIGATOP generators](https://arabellesolutions.com/our-technology/generators-for-nuclear-power-plants/gigatop-generators) Arabelle Solutions, 2025 2. [Air-cooled generators (GEN-A)](https://www.gevernova.com/gas-power/products/generators/air-cooled) GE Vernova, 2025 3. [Generators for power generation (product overview and references)](https://www.siemens-energy.com/global/en/offerings/power-generation/generators.html) Siemens Energy, 2025 4. [Harbin Electric wins bids for two 2 GW coal-fired power projects in China](https://www.enerdata.net/publications/daily-energy-news/harbin-electric-wins-bids-two-2-gw-coal-fired-power-projects-china.html) Enerdata, 2024 5. [GE HA Turbine Snags Another World Record for CCGT Efficiency](https://www.powermag.com/ge-ha-turbine-snags-another-world-record-for-ccgt-efficiency) POWER Magazine, 2018 6. [Engine Power Plants Surge as Data Centers Drive Unprecedented Demand](https://www.powermag.com/engine-power-plants-surge-as-data-centers-drive-unprecedented-demand/) POWER Magazine, 2026 7. [Dongfang Electric Corporation Limited: Annual results announcement for the year 2025](https://www1.hkexnews.hk/listedco/listconews/sehk/2026/0331/2026033103547.pdf) Dongfang Electric (HKEX filing), 2026 8. [Harbin Electric Company Limited: Annual results announcement for the year ended 31 December 2025](https://www1.hkexnews.hk/listedco/listconews/sehk/2026/0326/2026032603158.pdf) Harbin Electric (HKEX filing), 2026 9. [BHEL: order for 1x800 MW Anuppur thermal power project (stock exchange disclosure)](https://nsearchives.nseindia.com/corporate/BHELCC_03092025171754_BHELOrderReceipt.pdf) Bharat Heavy Electricals Ltd (NSE filing), 2025 10. [Shanghai Electric Power Generation Group (company profile)](https://www.shanghai-electric.com/group_en/dqdzjtwmdqy) Shanghai Electric, 2025 11. [Generac reports fourth quarter and full-year 2025 results](https://investors.generac.com/news-releases/news-release-details/generac-reports-fourth-quarter-and-full-year-2025-results) Generac Holdings, 2026 12. [Kohler Energy changes name to Rehlko](https://www.equipmentworld.com/business/article/15704847/kohler-energy-changes-name-to-rehlko) Equipment World, 2024 13. [Cummins Inc. Form 10-K for fiscal year 2025](https://www.sec.gov/Archives/edgar/data/26172/000002617226000009/cmi-20251231.htm) Cummins / US SEC, 2026 14. [The role of rare earth elements in wind energy and electric mobility (Alves Dias, Bobba, Carrara, Plazzotta), EUR 30488 EN](https://www.apren.pt/contents/publicationsothers/eu--the-role-of-rare-earth-elements-in-wind-energy-and-electric-mobility.pdf) European Commission Joint Research Centre, 2020 ## Other sections - [Summary](https://www.materialinsights.org/energy/e_generators/index.md) - [Overview](https://www.materialinsights.org/energy/e_generators/overview/index.md) - [Correlation](https://www.materialinsights.org/energy/e_generators/correlation/index.md) - [Science and limits](https://www.materialinsights.org/energy/e_generators/science/index.md) - [Value chain](https://www.materialinsights.org/energy/e_generators/valuechain/index.md) - [Unit economics](https://www.materialinsights.org/energy/e_generators/economics/index.md) - [Engineering methods](https://www.materialinsights.org/energy/e_generators/methods/index.md) - [Relationships](https://www.materialinsights.org/energy/e_generators/links/index.md)