GB452052A - Improvements in electrical power systems for driving auxiliary apparatus in boiler houses and the like - Google Patents

Abstract

452,052. Boiler plant. EASTWOOD, F. A., 46A, Poplar Grove, Brooklands, Cheshire, and ASSOCIATED ELECTRICAL INDUSTRIES, Ltd., Crown House, Aldwych, London. Feb. 22, 1935, No. 5803. [Class 122 (iii)] [See also Group XXXV] In boiler plant comprising a number of boilers of which some are run under steady service load and others used under variable load for regulating total output, the electrical power systems for driving auxiliary apparatus includes two sets of bus-bars energized at constant and variable frequency to which the units may be coupled according to whether steady speeds for units associated with service boilers or widely varying speeds for units associated with regulating boilers are required respectively. Two sets of bus-bars are provided, a main set 4 which is connected directly or through a transformer 5 with an alternating current supply 6 and a regulating-set 7 energized from an alternating current generator 8 driven by a motor 9 from the supply 6. The motor 9 has switching means 9a providing for different operating speeds and the generator 8 has switches 8a providing for different frequencies. The motors driving the auxiliary apparatus of the boilers 1, 2, 3 are provided with speedchanging means 10, 11, 12 and switches 13, 14, 15 permit of connection to either bus-bar system. With the boilers 1, 3 operating at service load, the motors of the associated equipment are coupled to the constant frequency main bus-bars 4, variation in speed being obtained by the pole-changing controls 10, 12. With the boiler 2 operating as a regulating supply, the motors therewith are coupled to the variable-frequency bus-bars 7 and a wider speed range is thus provided for. In a modification, the generator 8 is driven by an alternating current commutator motor with a shunt characteristic and shifting brushes.