Crane control equipments has introduced drum controllers intended for starting and speed control of ac slip ring induction motors driving various motions of cranes of all types and other machinery. The controllers are designed as per bs-58715:1822-1967 standard for motor starters and controllers. The controllers have direct stator reversing contacts as well as rotor resistance control. It has standard contacts with current ratings up to 250 a. For higher current ratings stator reversing is carried out through contactors for higher current ratings. Reversing contactors are controlled using auxiliary contacts given in the drum controller enclosure. The main contact fingers are of hinged pattern rigidly clamped to the bakelite insulated steel square bar. Each finger includes a heavy section bar fitted with a renewable hard drawn half round copper tip.
