Abstract :
The past year has shown a marked advancement in the art of electrical machinery, not only in the successful starting and operation of machines larger than any ever built up to this time, but also in the purchase and partial completion of machines still greater in size. Accompanying the trend towards larger sizes of units, there has been much investigation along the lines of ventilation, insulation, mechanical strength of materials, losses in iron and copper, the effect of expansion and contraction on the insulation of long armature coils, balance of the moving parts and the dissipation of heat from flat surfaces.
