Why choose a high-speed motor?

The motor output is decided in proportion to the rotor capacity and rotation velocity;
High rotation velocity enables the design of a high-output motor.

A high-capacity motor is operated by greater rotation velocity to obtain a high-output motor,
which leads to the reduction of the volume; it is possible to make a smaller and lighter motor.
Therefore, a high-capacity motor is advantageous because, as its motor runs fast,
designing a compact motor and obtaining a high output are possible.

Main Features

High Efficiency

Small Size

High Speed

Complex Cooling

design procedure

The main factors to be considered at preliminary design stage for high-speed induction motor are as follows.

01Electromagnetic design considerations :
additional high frequency losses, current density and
magnetic flux density and iron losses.
02Mechanical design considerations :
centrifugal forces acting on rotor surface, critical speed,
rotor slot shape and end-ring shape of rotor and losses of
windage and friction.
03System cooling considerations :
coolant passage on stator core, rotor cooling topology and
temperature rise of stator coil.

High-speed motor comparision

Aluminum rotor (Induction Motor)

principle

Rotary power generated by the interaction between the magnetic force from
stator coil current and another current flowing through a rotor bar (Aluminum)

Merits/demerits

Sturdy structure, long lifespan

Excellent for mass-production

Power factor declines at high-speed operation

Copper rotor (Induction Motor)

principle

Rotary power generated by the interaction between the magnetic force from the
stator coil current and another current flowing through a rotor bar (copper)

Merits/demerits

High efficiency, long lifespan, low noise, low vibration

Hard to manufacture; excellent for attaining high output

Power factor declines at high-speed operation

Excellent efficiency because of the decrease in rotor copper loss

Permanent Magnet Synchronous Motor

principle

Rotary power generated by the magnetic force from the stator coil current and
drawing force of a rotor permanent magnet

Merits/demerits

High efficiency, low noise, compact structure; high manufacturing cost

Risk of demagnetization of the permanent magnet

Excellent power factor, which leads to current reduction