Concepts of Gearless Bali Mill Drives

CIM Bulletin, 1970

P. HALE, Systems Engineer, Mining and Material Handling, lndustrial Systems Sales and Engineering, Canadian General Electric Company Ltd., Peterborough, Ontario

The trend to drives of more than 10,000 hp on largecapacity bali and autogenous mills for increased operating efficiency has been limited by factors in the conventional drive system. A solution to this problem, using modern developments in static converter technology, is the concept of driving the mill directly without gearing using a Jowspeed, Jow-frequency synchronous motor with a cycloconverter power supply. This paper presents various practical arrangements of mill and low-speed motors giving the specifie advantages of each system. The means of controlling inrush currents on starting and of spotting by the use of variable-frequency control are outlined in general form. Severa] gearless bali mill drives are scheduled for startup in European cement plants and further orders have been placed.
Keywords: Converters, Cycloconverter, cycloconverter, Hz, Peterborough, Ontario, synchronous motor, thyristor, Equipment, Frequency, Mill, Mills, Motors, Systems, Thyristors