an electric machine having a power ranging from fractions of a watt to several hundred watts with a shaft (rotor) rotation speed of up to 30,000 rpm. Such machines are divided into DC, AC, and universal types. They may have a variety of designs, depending on their purpose and service conditions. Miniature drives are used extensively in automatic, motion-picture, photographic, and radio apparatus; tachogenerators are used in systems having feedback elements, as well as in differentiators and integrators. Reluctance electric motors with concentrated stator windings, and also selsyns, are used in synchronizing systems; induction generators are used extensively in gyroscopes and radar equipment, as well as in electric servomechanisms. Stepping electric motors are most often used to drive mechanisms having a start-stop motion or mechanisms having a continuous motion in which the control action is provided by a series of electrical pulses, as in the case of the drives for machine tools with programmed control. Universal commutator electric motors are used in household electrical devices.
REFERENCESArmenskii, E. V., and G. B. Falk. Elektricheskie mikromashiny. Moscow, 1968.
Bruskin, D. E., A. E. Zorokhovich, and V. S. Khvostov. Elektricheskie mashiny i mikromashiny. Moscow, 1971.
IU. M. IN’KOV