Air-Cooled Generators

Simplicity & Flexibility

GE's air-cooled generators are an ideal choice for power system applications that demand simplicity and flexibility of operation. The absence of a pressurized atmosphere within the generator makes its structural components simple, facilitating maintenance.

We offer a complete line of air-cooled generators up to 191 MVA for either 50 or 60 Hz applications that are designed for maximum safety and reliability. The reliability of GE air-cooled generators exceeds industry levels with mean time between failures up to twice the industry average.

Features & Benefits

Air-cooled generators operate with either an open-loop or a closed-loop cooling system. In the open-loop system, the generator draws air from the atmosphere to cool its active components, and exhausts the air into the atmosphere. In the closed-loop system, cooling air is recirculated continuously through the generator while air-to-water heat exchangers remove heat from the air.

One of the most important elements of a generator's design is the effectiveness of its insulation system. GE is constantly refining our proprietary family of Micapal™ insulation systems to enhance material performance characteristics such as thermal heat transfer and dielectric strength. This evolutionary approach to insulation development assures our systems' maximum performance and outstanding reliability.

The potential for severe corona discharge damage is a challenge to the design of air-cooled generators. GE uses a well-proven system of insulating and voltage-grading materials to ensure freedom from damaging corona activity.

GE air-cooled generators are fully assembled before they are shipped, limiting on-site assembly to placement on the foundation, alignment with the turbine and connection to balance of plant equipment. The resulting reduction in construction time represents a direct cost saving to the customer.

  • Fully assembled package options are available for delivery with the rotor already installed.
  • Class F insulation on both the rotor and stator provides dielectric and mechanical strength to assure long life.
  • Direct-cooled field promotes uniform temperature distribution throughout the windings to lower temperature rise and prolong insulation life.
  • Tilt-pad pedestal bearings minimize vibration during operation and incorporate a special seal design to prevent oil leakage. Both the generator and turbine are served by a common lubricating oil system.
  • Excitation options include brushless excitation with redundant rotating rectifiers to maximize availability and high initial response potential and compound source static exciters.
  • Cooling configuration may be either Totally Enclosed Water-To-Air Cooled (TEWAC) or Open Ventilated (OV) with self-cleaning filters and inlet silencers.
  • Low-loss stator core, made of grain-oriented silicon steel, minimizes electrical losses within the core to increase machine efficiency.
  • Retaining rings of 18-Manganese / 18-Chromium, non-magnetic stainless steel resist stress-corrosion cracking.
  • Flush-mounted fans at each end of the rotor circulate air to cool the unit and boost generator efficiency.

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