ABSTRACT
Field theories proved static and dynamic end effects as the main differences between rotary and linear induction motors (LIM). The dynamic end effect divides the LIMs into high-speed and low-speed LIMs when the dynamic end effect is negligible. There are a few basic topologies for low-speed LIMs: flat double-sided LIM with Al sheet secondary; flat single-sided LIM (SLIM) with Al-on-iron secondary; flat SLIMs with ladder secondary; and tubular SLIMs with cage secondary. Tubular SLIM may be favored in short length travel applications due to zero net radial force between primary and secondary and practically zero end connections of short-primary circular coils. An experimentally based method that measures the LIM equivalent impedance at a few representative speeds, slip frequencies, and primary currents may also be used to identify the equivalent circuit curve fitting, to estimate the equivalent circuit parameters. An exhaustive solution for high-speed LIM transients would imply using the 3D-FE coupled field/circuit method.
