Unit 2 Main Generator

Question 1

What cools the stator?

Answer 1

Stator cooling water

Question 2

Describe the flow path through the U2 main generator and excitation system from the pilot exciter to the main transformer.

Answer 2

Pilot Exciter, Step down transformer, Exciter field breaker, Voltage regulator (converters), Main Exciter brushes, Main Exciter field rectifiers, Main generator brushes, Main transformer.

Question 3

How do you locally trip the Exciter Field Breaker?

Answer 3

Push the off button on the breaker in the cabinet on the 609’.

Question 4

What is the purpose of the main generator?

Answer 4

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

Question 5

What does the Excitation system do?

Answer 5

It provides the necessary power fo the generator field.

Question 6

What cools the rotor?

Answer 6

Hydrogen.

Question 7

What does seal oil do for the generator?

Answer 7

Keeps Hydrogen in the generator and Oxygen out.

Question 8

What voltage dose the pilot exciter produce?

Answer 8

575vac

Question 9

What dose a red light on the rectifier cabinet mean?

Answer 9

Blown rectifier fuse.

Question 10

What do the converters do?

Answer 10

Turn AC to DC

Question 11

What do the rectifiers do?

Answer 11

Turn AC to DC

Question 12

What does the the generator condition monitor look for?

Answer 12

Products of combustion.

Question 13

What is the out put of the main generator?

Answer 13

26,000vac

Question 14

Why do we use hydrogen in the generator?

Answer 14

High thermal conductivity and low windage.

Question 15

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

Answer 15

The fan on the rotor in the generator.

Question 16

A loss of hydrogen pressure will result in overheating of what part of the Unit 2 main generator?

Answer 16

The rotor.

Question 17

Main generator voltage is controlled by adjusting the?

Answer 17

Main exciter field.

Question 18

What cools the main exciter in Unit 2?

Answer 18

Air cooled by TACW.

Question 19

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 19

0. Because the mode of force to push the hydrogen through the monitor is the fan on the generator rotor.

Question 20

Where do you read the U2 pilot exciter voltage?

Answer 20

609’ on the ECT.

Question 21

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

Answer 21

On the Generator condition monitor current output is not between 70% and 95%.
Below 70% and above 95% gives you an alarm.

Question 22

The failure of which one of the following components would prevent any operation of the Unit 2 Main generator?

1. An Exciter slip ring.
2. One bank of Field Rectifiers.
3. One voltage regulator converter.
4. The pilot exciter.

Answer 22

1. An Exciter slip ring.