History (1979): IMI 7700 Series

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1979: IMI 7700 Series
First brushless dc spindle motor

Why it’s important
While initially somewhat more expensive, the brushless dc spindle motor eliminated the need for AC power and belt/pulley mechanisms, thereby lowering costs, allowing smaller sizes and ultimately lower costs.

IMI 7710 Winchester HDD

By the end of the 1980’s all drives were announced with DC motors.

Discussion
Early (if not first) and perhaps last plastic base casting.

Additional information
US Patent 4,337,491, Brushless DC Motor Assembly jointly invented by IMI and Papst Motorwerken
IMI 7700 Series Data Sheets