Highlights

Two-Pole Generators. The unequal mechanical rigidity of the rotor body on the two major axes and unequal magnetic forces on any two major axes of the stator core produce vibrations in two-pole generators that become of increasing importance in 3,600-rpm units of relatively large capacity; the disturbing force may be eliminated or the vibration restricted to isolated parts (Transactions pages 30–4). Critical speeds of rotors may be predetermined analytically and stresses determined by the photoelastic method; control of bearing lubrication promises increased efficiency (Transactions pages 51–6).