ABB is number one in gearless mill drives and combines its extensive industry knowledge with its application experience to select the most economical drive solution for your particular circumstances. In 1969, ABB commissioned world’s first GMD, an 8600 horsepower (6400 kW) motor for a ball mill at Ciments Lambert-Lafarge in Le Havre, France. This unit is still in operation today. With over 100 GMD’s on order or in operation, ABB has an unmatched experience and is the world market leader.
The wrap around motor is designed with so-called Roebel bars for the stator winding, which have a positive impact on the efficiency. ABB’s design is furthermore based upon single rotor poles and each pole can be adjusted individually by the use of eccentric sleeves for the pole mounting bolts. With this unique concept wider tolerances for the mill flange can be accepted, while an almost perfect run out can be achieved hence less unequal magnetic pull.
The stator of ABB is quit stiff; because ABB’s design philosophy is that the maximum pole passing frequency is always below the first critical natural frequency of the stator in order to avoid possible resonance problems during start-up and operation.