Fire protection of water-wheel type generators

In recent years, much attention has been given to fire protection of turbo generators, resulting in a trend towards closed ventilating systems and the use of inert gas to smother combustion. Water-wheel type generators are not so well adapted to this method of protection. In water-power plants, water is the most readily available means for fire extinguishment, but its indiscriminate use through perforated pipes or nozzles may cause damage equal to that of the fire. The present paper describes a system of fire protection for water-wheel type generators which is designed to limit both fire and water damage to the section of the generator immediately adjacent to the point of origin of the fire. This is accomplished, first, by air baffles which control the flow of ventilating air around the armature end projections, and second, by the use of fusible sprinkler heads which permit the application of the water solely to the region of the fire. The means for preventing and detecting fires in such generators are also outlined. Tests made during design to establish the effectiveness of the scheme and devices used are also described.