High-Efficiency Synchronous Motors with Permanent Magnets

Synchronous Motors (PMSM) and Line Start Permanent Magnet
Motors (LSPMM). LSPMM are well recognized and used, also in the
heavy industry in the drives which do not need a change of the
rotation speed, but they can not drive the machines requiring high
starting torque or machines with big inertia torque (for example, mills
or belt conveyors while fully loaded during start-up). The novel
design of LSPMM with winding in the rotor was developed,
described, manufactured and tested. LSPMM with winding in the
rotor (LSPMMwWR) do not need frequency inverters for start-up
and operation, and that kind of motor can be used for driving
machines with big inertia torque or machines requiring high and
long-lasting starting torque. The advantage of LSPMMwWR over
LSPMM is characterized mainly by minimizing thermal losses in the
rotor, which do not cause thermal overheating of permanent magnets,
and also by higher starting torque. The experimental model of the
LSPMMwWR was manufactured and tested, and the results are
presented in the paper. Additionally, the paper shows an example of
the use of PMSM in suspended trains for underground applications
in coal mines. The train and the motors are supplied from lithium-ion
batteries designed and tested for the explosion-risk areas.