Axial Flux Ironless Permanent-Magnet Motor/Generator

This is a brushless DC machine with permanent magnets, axial flux, slotless and coreless. These motors have no iron in the stator and the only losses present in the core are conduction losses and eddy current losses in the copper.

Technology

The discovery of new high field, rare-earth permanent magnet (PM) materials has shown great opportunities for novel topologies of electrical machines.

The machine consists of two outer rotor disks and one coreless stator in the middle. On the two opposing rotor disks there are surface mounted permanent magnets. The stator windings consist of a number of concentrated coils. The coils are held together and in position by using an epoxy resin. Unlike conventional PM (permanent magnet) machine, the magnetic field is in the axial direction.

Advantages

Zero iron loss
High efficiency
Zero cogging torque
Better stability and easier tuning
Smooth operation at very low speed
Reduced audible noise
Low volume
Fewer components
Less generated heat
Maintenance free
Zero positional displacement of the servo axis after the servo amplifier inhibition, due to the absence of detent torque
Torque is proportional with the current
Reduce torque ripple
Maximum current approx. 10 times nominal current datasheet (.pdf)
High efficiency
Low inductance

Technical specifications

Resistance: 0,144 Ω
Inductivity: 0,128 μH
Number of magnetic poles: 24
Electromotive voltage: 70 V/krpm
Inertia: 148 kgcm²
Total weight: 40 kg
Insulation class: F
Generator
- Nominal power: 1400 W
- Nominal speed: 370 rpm
- Nominal current: 38 A
Motor
- Nominal torque: 40 Nm
- Nominal speed: 1000 rpm
- Nominal current: 39 A
- Stall torque: 42 Nm
- Stall current: 41 A

Applications

Machine tools
Robotics
Traction drives
Packaging machines
Textile machine
Food processing
Sorting machines
X, Y Tables
Direct drive motors
Wind/Water generators