include permanent-
magnetic, printed-circuit, and moving-coil (or shell)
dc servo motors. The rotor of a shell
dc servo motor consists of a cylindrical shell of copper or aluminum wire coils which rotate in a
magnetic field in the annular space between
magnetic pole pieces and a stationary iron core. The servo motor features a
field, which is provided by cast AlNiCo magnets whose
magnetic axis is radial. Servo motors usually have two, four, or six poles.
DC servo motor characteristics include...
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