Rotors. All induction motors shall have squirrel-cage rotors. Motors utilizing fabricated aluminum alloy cage construction rotors will be considered for acceptance only if the proposal data includes, for each proposed motor application, data indicating multiple utility experience for motors driving comparable equipment for at least 5 years. This data shall include user's name, application, horsepower, voltage, rpm, driven equipment inertia (WK2), and years in service. All motor rotating components shall be dynamically balanced after mounting of the shaft.
Rotors. All induction motors shall have squirrel-cage rotors adequately sized to avoid overheating during acceleration of the motor and driven equipment. Rotors shall be dynamically balanced.
Rotors. 1. Die cast aluminum or brazed copper construction. 2. Epoxy protected corrosion on external surfaces. 3. Free from inherent axial thrust and be balanced to within NEMA Standard MG 1-12.05 vibration
Rotors. The development plan for rotors will focus on vented rotors. The major activities in this vented rotor development plan are: process improvement, product improvements, cost reduction, and development of machining/grinding practices. Process improvement activities would consist of developing a cost effective method for producing the vented preforms and mix optimization for higher green strength and for improved blow mold die filling. Options for producing vented preforms could be cores used in a blow molding machine, blow molding two pieces and joining, and blow molding dies designed with retractable fingers. Product improvement activities would be directed toward improving operating temperatures, etc. in order for aluminum MMC rotors to meet the specifications for a larger number of platforms. Efforts would continue in the area of cost reduction. Each of the existing operations would be evaluated and re-engineered if necessary to reduce operational cost and improve yields. This process would be done with the objective of process scale-up. Improvements in near net shape of the preforms would be addressed in the work to develop green machining/grinding. This would produce a preform close enough to final dimensions such that grinding of the composite becomes feasible. When the green machining/grinding technique was developed equipment would be purchased and added to the rotor line. The grinding process for the composite will be developed and equipment acquired to add this operation to the rotor line.
