The synchronous permanent magnet motor (PM) is an innovative development in the field of
electric motors that combines high precision in the speed control typical of the synchronous motor with the
simple and robust design of an asynchronous squirrel-cage motor.
Mechanically, the PM motor is similar to the traditional asynchronous induction motor, however, in terms of performance it can deliver
clearly superior results. The PM motors of the “6S4 – 7S4” series are made from
rotors with permanent magnets with rare-earth internal elements, which generate a constant magnetic field; the
rotor rotates at exactly the same speed as the magnetic field generated by the windings of the
stator, regardless of the torque required by the shaft, while in the common asynchronous motor, there is
a sliding proportional to the developed torque. Therefore, there are no losses linked to
rotor magnetization, which results in less use of electricity to produce mechanical energy
and less heating of the motor itself.
Synchronicity, therefore, improves dynamic performance by offering consistent torque in a wide range of
speeds, high performance even when operating at low frequencies (efficiency levels are much higher than those of
asynchronous motors) and without the need to use forced ventilation; constant torque at various rotation speeds
can also simplify the moving chain, with all the benefits
thereof.
Permanent magnet motors can be used in several industries. In particular, they are ideal for industries
where weight, the size of the casing and the maintenance costs are crucial. Accordingly,
they are suitable to be installed in pumping, HVAC ventilation and transmission systems; in
compressors and elevators, but also in many types of industrial machinery, for example for the
textile, metallurgy, and paper sectors.
The most significant design benefits of permanent magnet motors are:
- High efficiency
- High yields throughout the speed range, especially at low rpm where efficiency is better than that of asynchronous motors
- Reduction of rotor losses
- Constant torque over the entire speed range
- High power density
- Precise control speed even without encoders
- Reduction of over-temperature resulting in an increase in the service life of insulation, bearings and other motor components
- Reduced motor footprint and weight
- Fast payback time
- PM Permanent Magnet motors can only work with the help of an inverter.
Elvem can provide its customers with complete systems: PM motors with integrated or separate inverter.
