Shaft seal assembly for hydrogen cooled turbine generator

A seal assembly forming a seal with a rotatable shaft of a hydrogen-cooled generator, the seal assembly comprising:

• a ring assembly disposed about the rotatable shaft and including a fluid inlet and a fluid outlet, said ring assembly comprising:
• a first side ring coupled to a generator frame of the generator;
• an insulating structure positioned between said first side ring and said generator frame to provide electrical insulation between said first side ring and said generator frame;
• a second side ring coupled to said first side ring, wherein said second side ring is not in direct contact with said generator frame;
• seal structure coupled to one of said first and second side ring;
• and
• structure for supplying oil to said ring assembly, such that the oil flows through said ring assembly to an interface between the rotatable shaft and said seal structure so as to substantially limit direct contact between the rotatable shaft and said seal structure.

A method of servicing a seal assembly forming a seal with a rotatable shaft of a hydrogen-cooled generator, the seal assembly comprising a ring assembly including a hydrogen side ring coupled to a generator frame of the generator, an insulating structure positioned between the hydrogen side ring and the generator frame, an air side ring coupled to the hydrogen side ring, and seal structure coupled to the air side ring, the method comprising:

• removing the air side ring from the hydrogen side ring;
• servicing the air side ring;
• and
• coupling the serviced air side ring to the hydrogen side ring;
• wherein the insulating structure between the hydrogen side ring and the generator frame remains intact during said removing the air side ring from the hydrogen side ring and said coupling the serviced air side to the hydrogen side ring.