Phanotron rectifiers as a D-C supply for elevator motors

THERE ARE a number of public utilities that have instituted programs for curtailing and in some cases completely eliminating the d-c power supply to concentrated load areas. The change from d-c to a-c power supply for elevators in the affected areas requires the substitution of a-c elevator equipment or the use of converters to supply d-c to the existing elevator equipment. Elevators may be operated equally well from either alternating current or direct current, so the choice is dependent upon the cost of the change-over.