Dual source auxiliary power supply

Abstract

An auxiliary power supply system for providing controlled alternating current in an electric motor traction vehicle driven by a prime mover through a traction alternator. During normal traction operation the prime mover operates at a high constant rotational speed to directly drive an auxiliary alternator which provides the auxiliary power, while in standby operation the prime mover operates at a reduced constant rotational speed and the auxiliary power is obtained from the traction alternator at the desired frequency and voltage.

What I claim as new and desire to secure by Letters Patent of the United States are: 
     
       1. In a traction vehicle of the type wherein thermal prime mover means drives a traction alternator having a predetermined number of .[.commutating.]. poles and adapted to energize traction motor means, an auxiliary power arrangement adapted to produce alternating current, the combination comprising: a. an auxiliary alternator having a plurality of .[.commutating.]. poles .[.greater.]. .Iadd.less .Iaddend.than the number of poles of said traction alternator;   b. means for mechanically coupling said prime mover means to said auxiliary alternator;   c. governor control means for maintaining the shaft speed of said prime mover at a first predetermined shaft speed during normal operation of said traction vehicle and at a second predetermined reduced speed during standby operation of the traction vehicle;   d. an alternating current circuit having an output adapted to energize auxiliary power circuits and an input;   e. switching means to connect said input to the output of said auxiliary alternator during normal operation of said traction vehicle, and to connect said input to the output of said traction alternator during standby operation of said traction vehicle;   f. wherein the number of .[.commutating.]. poles of said auxiliary alternator is substantially equal to the product of the number of .[.commutating.]. poles of said traction alternator and the ratio of said .[.first.]. .Iadd.second .Iaddend.predetermined shaft speed to said .[.second.]. .Iadd.first .Iaddend.predetermined shaft speed.   
     
     
       2. The auxiliary power source of claim 1 and including control means having an input connected to be responsive to the traction power applied to said traction motors and an output connected to regulate the excitation of said traction alternator, wherein during standby operation of said vehicle, said control means is connected to be responsive to the output of said alternating current circuit. 
     
     
       3. A traction vehicle propulsion system as defined in claim 2 wherein said control means is effected by a reference current, said reference current during normal operation being variably responsive to said governor control means and during standby operation being a constant current of .[.of.]. a predetermined magnitude.