The SM 7840 Alternator Rotor Assembly is a high-performance electrical component specifically designed for Bosch-style (B. Type) charging systems used in Tata Motors' 12-Volt Turbo-Charged (T.C.) engine range. Built to O.E. (Original Equipment) Specifications, this rotor is engineered to handle the increased RPM fluctuations and higher engine bay temperatures typical of turbocharged diesel platforms like the Tata 407 T.C., 709 T.C., and early 1109 models.