Operation of Alternators with Parallel-Bridge Rectifier Systems

Three-phase alternators having high commutating reactances supplying resistive dc loads through parallel-bridge rectifier systems experience nearly balanced load conditions, continuous conduction for load resistances less than or equal to (l/√3) times the commutating reactance per phase and no line-to-line short circuits. This paper presents a discussion, supported by a detailed oscillographic record, of the operation of alternators with parallel-bridge rectifier systems. It also develops a method to predict the dc excitation current required to supply a dc load at any specified voltage and current. Experimental verification of the method shows excellent agreement over the entire range of operation. The results and discussion should be of significant value to those involved in the design and development of systems having rectified output synchronous machines.