Abstract The laminae or punchings forming the rotor core are arranged in groups in stack formation. All the punchings are of identical shape and are formed with radially disposed slots which are, in the assembled rotor, aligned to form conductor bar receiving slots extending lengthwise of the rotor core. The slot in each punching is formed with an outer narrow portion and an inner wider portion. A projection extends from one side wall of the wide inner portion of the slot toward the opposite side wall thereof. The punchings in certain groups are arranged with the projections therein at one side of the rotor slot. In the intermediate groups, the projections are located at the opposite side of the rotor slot. Such arrangement provides a tortuous passage for reception of cast conductor bars, the projections serving to limit shrinkage of the bar metal in directions lengthwise of the rotor slot and also radially.
A rotor having a squirrel cage winding and comprising a plurality of circular magnetic steel punchings of identical form arranged in groups in stack formation on a shaft, each punching being formed with a circular series of radially disposed slots, said slots being formed with outer narrow portions in the periphery of the punching and with inner wider portions, said inner portions being formed in one side wall thereof with a projection extending transversely of said wider portion toward the opposite siDe wall thereof and terminating in spaced relation thereto, the end edges of said projection converging toward said opposite side wall, said punchings in said stack formation being arranged with the slots in said punchings forming elongated rotor slots extending lengthwise of the rotor, the punchings in certain of said groups being arranged with said projections positioned at one side of said rotor slot, the punchings in intermediate groups having said projections on the opposite side of said rotor slot, said projections extending toward said opposite side wall a distance less than one-half of the width of said inner wider portion of the slot, and conductor bars cast in said rotor slots.
Claim 2
Dependent Claim
193 words
A rotor having a squirrel cage winding and comprising a plurality of circular magnetic steel punchings of identical form arranged in groups in stack formation on a shaft, each punching being formed with a circular series of radially disposed slots, said slots being formed with outer narrow portions in the periphery of the punching and with inner wider portions, said inner portions being formed in one side wall thereof with a projection extending transversely of said wider portion toward the opposite siDe wall thereof and terminating in spaced relation thereto, the end edges of said projection converging toward said opposite side wall, said punchings in said stack formation being arranged with the slots in said punchings forming elongated rotor slots extending lengthwise of the rotor, the punchings in certain of said groups being arranged with said projections positioned at one side of said rotor slot, the punchings in intermediate groups having said projections on the opposite side of said rotor slot, said projections extending toward said opposite side wall a distance less than one-half of the width of said inner wider portion of the slot, and conductor bars cast in said rotor slots.
Claim 3
Dependent Claim
39 words
A rotor structure as set forth in claim 1 wherein said inner wider portions of the slots in said punchings are formed with end walls, the end edges of said projections extending in spaced relation to said end walls.