U2 Main Generator &Excitation

Question 1

Describe the flow path for the U2 main generator and excitation systems from the pilot exciter to the main transformer.

Answer 1

Pilot Exciter, Step down transformer, Exciter field breaker, Voltage regulator (converters), Main Exciter Brushes, Main Exciter, Field Rectifiers, Main Generator Brushes, Main Transformer.

Question 2

How do you locally trip the Exciter Field Breaker?

Answer 2

Push the off button on the breaker. 609’

Question 3

What is the purpose of the Main Generator?

Answer 3

To convert mechanical energy from the main turbine into electrical energy.

Question 4

What does the Excitation system do?

Answer 4

It provides the necessary power for the main generator field.

Question 5

What cools the Rotor?

Answer 5

Hydrogen.

Question 6

What does seal oil do for the generator?

Answer 6

Keeps the Hydrogen in the generator and oxygen out.

Question 7

What voltage does the pilot exciter produce?

Answer 7

575vac

Question 8

What is another name for the pilot exciter?

Answer 8

Permanent Magnet Generator.

Question 9

What cools the Stator?

Answer 9

Stator water.

Question 10

What are the TACW loads?

Answer 10

Hydrogen coolers.
Exciter air coolers.
Bus duct coolers.
Gland steam exhauster.
Stator cooling water.

Question 11

What does a red light on the rectifier cabinet mean?

Answer 11

Blown rectifier fuse.

Question 12

What do the converters do?

Answer 12

Turn AC into DC

Question 13

What do the rectifiers do?

Answer 13

Turn AC into DC.

Question 14

What does the generator condition monitor look for?

Answer 14

Products of combustion.

Question 15

What is the output voltage on U2 main generator?

Answer 15

26,000vac

Question 16

What cools the Stator?

Answer 16

Stator water.

Question 17

What are the TACW loads?

Answer 17

Hydrogen coolers.
Exciter air coolers.
Bus duct coolers.
Gland steam exhauster.
Stator cooling water.

Question 18

What does a red light on the rectifier cabinet mean?

Answer 18

Blown rectifier fuse.

Question 19

What do the converters do?

Answer 19

Turn AC into DC

Question 20

What do the rectifiers do?

Answer 20

Turn AC into DC.

Question 21

Why do we use hydrogen in the generator?

Answer 21

High thermal conductivity.

Low Windage.

Question 22

What is the mode of force to move hydrogen through the condition monitor?

Answer 22

Fans on the rotor in the generator.

Question 23

If you lose hydrogen pressure in the generator what will overheat?

Answer 23

The rotor.

Question 24

Main generator voltage is controlled by adjusting what?

Answer 24

The main exciter field.

Question 25

What cools the main exciter?

Answer 25

Air cooled by TACW.

Question 26

The U2 main turbine is on the turning gear with generator hydrogen pressure being maintained at 60psig. What should the flow rate through the generator condition monitor indicate? And why?

Answer 26

0. The mode of force to get hydrogen through the condition monitor is the fans on the rotor in the generator.

Question 27

Where do you read the U2 pilot exciter voltage?

Answer 27

609’ on the ECT.

Question 28

The control room has asked you to verify a “Generator Internals Overheated” alarm. You confirm this by verifying the local indication on what?

Answer 28

Generator condition monitor current is less than 50%.