Axial Flux Motors
Axial flux motors are excellent for low profile applications: moving cameras, gimbals and scanning or imaging systems. These motors are slotless and therefore have zero cogging torque. The axial flux motor is easy to manufacture and typically the lowest cost solution for direct drive rotation. The motor also scales to large diameters with a seamless transition to a modular construction. Motors with a diameter of 2 meters or greater are currently made by Sierramotion.
Axial Flux Motor specifications
|Diameter range||20mm to 2 meter|
|Axial length range||3mm to 50mm|
|Through hole range||10mm to 1.8 meter|
|Torque range||.005 NM to 1000 NM|
|Electrical resistance||100 milli-ohm to 100 ohm|
|Speed range||1 rpm to 10,000 rpm|
|Temperature range||-50°C to + 70°C with option to < 200°C|
|Vacuum operation||Laser welded enclosure for >10E-9 Encapsulation for <10E-6|
Frequently asked questions
Torque is produced through a magnetic field interaction that is axial rather than radial. These motors lend themselves to be very low profile axially. The axial flux motor is similar to a linear motor that is bent around in a circle. It is naturally a moving magnet motor.
As with many motor types, if an iron core is present then then cogging torque is typical. Most axial flux motors to not have iron cores and therefore they do not exhibit cogging torque.
It all depends on motor construction. Axial flux motors that are also slotless would produce less torque than radial flux motors. If iron is used between the coils, axial flux motors can have very high torque rivalling radial flux motors if multiple stacks are use to make the equivalent motor length.
Axial flux motors have multiple stator coils adjacent to permanent magnets and have iron only between the coils (if there is iron at all). Transverse flux motors use iron in three dimensions and a simple toroidal coil centrally located to create the electromagnetic field.
Most small motors including axial flux motors operate on low voltage, 24-80 volts DC. Larger versions can operate up to 600 volts with the proper insulation system and a control system that can handle the motors’s low inductance.