D-C magnetic crane hoist control for A-C powered cranes

The use of a d-c series-wound motor, series-wound motor brake, and power-type overhoist limit switch for the hoist drive of an otherwise all a-c powered crane is highly desirable. Time proven safety and simplicity of d-c dynamic lowering hoist systems can now be further improved in performance, and better motor stability is possible when d-c power is made available through metallic plate rectifiers.