Alternators for Steam & Gas Turbines

Steam & gas turbines are widely used in utility and prime power plants, where their global efficiency and reliability is appreciated.

For alternators, turbines pose specific challenges. Leroy-Somer has developed a complete range of solutions and technologies to offer alternators that are perfectly suited for use with steam or gas turbines.

Leroy-Somer alternators for steam & gas turbines

• 4 pole generators - 50 Hz or 60 Hz
• Available from 380V up to 15kV
• Power output up to 35,000 kVA 
• Class H insulation
• Design suitable for ODP, CACW or CACA cooling
• Horizontal mounting with antifriction or sleeve bearings
• Axial-radial or symmetrical ventilation
• Very high performances: power density, reactance & stability, high efficiency, low noise emission, very low vibration level
• Lots of optional accessories and customization

Built for speed

Turbines typically have higher rotation speed than reciprocating engines, which require 4 or 6 pole design for the alternator rotor, and an optimized construction to withstand centrifugal force. Alternators for steam or gas turbines are also designed to be more compact to match the footprint advantages offered by the prime mover, decrease physical stress and improve transient electrical performances such as reactance.

Balance to protect

Vibration is another challenge when using turbines. With diesel or gas engines, engine vibration can damage the alternator. In the case of turbines, the situation is reversed: the drive system will generate very little vibration, but the balancing of the alternator must be optimized and thoroughly tested so that its vibration may not damage the turbine. This is why Leroy-Somer offers G1-class balancing on its generators intended to be coupled with turbines, guaranteeing a perfect balance of the entire installation.

Enclosures & cooling technologies

Generators coupled to steam or gas turbines are usually subjected to harsh environmental conditions, with the presence of steam, moisture, heat and particles that put the electrical and mechanical parts to the test. To meet these requirements, Leroy-Somer offers adapted protection systems and has developed specific know-how in the design and production of closed machines with air-water heat exchanger cooling systems, according to the IP54 standard.

Performance & reliability for prime power projects