Turbomachinery Package Specification

Titan 250 Generator Set

 

 

Any variations in bus potential will also be sensed and corrected by this circuit. After voltage builds, the generator accelerates to 100% speed and excitation and voltage control is assumed by the CGCM. A crosscurrent-compensating transformer provides the signal to the CGCM for reactive loadsharing between multiple paralleled units.

It should be noted that the generator rotor windings rotate and the generator armature is stationary. The exciter field coils are also stationary and the exciter armature rotates with the main generator rotor shaft. As a result, a single rotating assembly consisting of the exciter armature, exciter rectifier, and the generator rotor windings is formed. This single rotating assembly greatly simplifies all electrical connections within the generator.

5.2.1Standard Features

Generators include the following standard features:

•Sleeve bearings with pressure fed sumps

•Terminal box

•Form wound stator windings

•Amortisseur windings

•Rotor balance to 125% rated speed

•Anti-condensation space heaters

•Permanent magnet generator (PMG)

•Rotating armature-type VAC exciter

•Full-wave rectifier assembly

Special order generators are available to meet unique customer requirements including non-U.S. specifications.

5.2.2Rotor

The salient, four-pole, forged rotor is dynamically balanced to minimize vibration. Motor fans move cooling air through the generator and around the rotor. The rotors have layer-wound field windings cemented with a high-strength resin and are baked to cure the resin. The rotor is in electrical and mechanical balance at all speeds up to 125% of rated speed.

5.2.3Stator

The stator is built with high-grade silicon steel laminations that are precision-punched and individually insulated. Windings are typically form-wound and treated with thermosetting synthetic varnish or vacuum pressure impregnated (VPI) epoxy for maximum moisture resistance, high dielectric strength, and high bonding qualities. The windings are braced to withstand shock loads such as motor starting and short circuits. Space heaters can be supplied to minimize condensation during shutdowns.

5.2.4Shaft

The shaft diameter provides the necessary stiffness to avoid torsional vibration. The turbine-driven generator set is given a complete torsional analysis.

5.2.5Frame

The frame is heavy-duty steel and is fabricated with deep welds and internal reinforcing for extra rigidity and strength. The frame also includes lifting lugs.

5.2.6Exciter

Excitation current for the generator field coils is provided by a brushless rotating exciter with a PMG pilot exciter. The exciter is mounted directly on the generator rotor shaft. The exciter consists of two basic parts, a small three-phase, AC generator with rotating

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TPS250GS/908 - Preliminary

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