Generator hydrogen/Carbon dioxide

Question 1

What’s a spool piece and why is it used?

Answer 1

Piece of pipe that is rotated 90 degrees to prevent unintentional cross-connection of the two systems

Question 2

What is used to purge hydrogen from primary water tank and why?

Answer 2

Nitrogen instead of CO2 to prevent carbonic acid forming causing corrosion

Question 3

What is cooled by hydrogen?

Answer 3

Stator core

Question 4

Explain sequence for gassing generator?

Answer 4

Instrument air, then CO2, then hydrogen

Question 5

Explain sequence for de-gassing the generator?

Answer 5

Hydrogen, then CO2, then instrument air

Question 6

What’s the explosive range for hydrogen?

Answer 6

4-74% (combustible and explosive range…)

Question 7

What pressure is generator filled to with hydrogen? why?

Answer 7

72 psig to allow for expansion on heatup

Question 8

What pressure is hydrogen maintained at in generator?

Answer 8

75 psig

Question 9

Explain how the gas drying tower operates

Answer 9

1 tower is in service 8 hours while other tower heats for 4 hours (to dry moisture). Then cools 4 hours (to normal temp)

Question 10

What cools hydrogen coolers?

Answer 10

TBCW

Question 11

What % purity is hydrogen maintained at in the generator?

Answer 11

98%

Question 12

What temp is hydrogen maintained at relative to primary water? why?

Answer 12

hydrogen maintained 2 deg F below primary water to ensure no condensation occurs in windings

Question 13

Why is hydrogen used?

Answer 13

Less windage losses