Special fire protection equipment is sometimes used to quickly extinguish fires within
the generator housing [l ]. One method that has been used releases water into the generator
enclosure on detection of a fire. A better system injects carbon dioxide into the generator
rather than water. This is safer and does not add to the damage caused by the fire.
Many large machines operate in a hydrogen cooled environment. Since hydrogen will
not support combustion, additional fire protection is often not considered necessary for these
units. Instead, a method is required to monitor the purity of the hydrogen to make sure no air
is mixed with the hydrogen to form an explosive mixture. Most generator shells are designed
to withstand such an explosion of the maximum intensity possible from a hydrogen and air
mixture.