Metal-clad synchronous motors latest thing for nitrate plants

WORKING in an atmosphere of fine nitrate dust, the 250-hp. Westinghouse synchronous motor shown under construction in the accompanying illustration, obviates the usual danger of nitric-acid damage to its windings. Built to fit their job, the vulnerable parts of these motors are metal-clad and in addition are supplied with a slight static pressure inside to prevent the harmful dust from leaking in. Inclined fins on the metal enclosure not only throw off heat, but guide along the most efficient route the cooling air supplied by the fan on the rotor. Without these odd-looking fins the operating temperature of the motor would be much higher. These motors are designed to operate on 550-volt, 60-cycle circuits and have a synchronous speed of 450 r. p. m.