Technical Information Brushless DC-Motors

The FAULHABER winding

Originally invented by Dr. Fritz Faulhaber Sr. and patented in 1958, the System FAULHABER coreless (or ironless) progressive, self-supporting, skew-wound rotor winding is at the heart of every FAULHABER DC-Motor. This revolutionary technology changed the industry and created new possibilities for customer application of DC-Motors where the highest power, best dynamic performance, in the smallest possible size and weight are required. Applied in a three phase brushless motor, the winding no longer rotates but rather becomes the basis of a slotless stator.

Brushless DC-Motor Types

Whether it’s high torque 4-pole DC-Servomotors, highly efficient flat DC-Micromotors, or compact slotless motors, FAULHABER specializes in getting the most performance out of the smallest package.

Due to their design FAULHABER Brushless DC-Motors are ideal for heavy duty servo applications with frequent overload conditions as well as for continuous duty applications where maximum operational lifetime is required.

FAULHABER high precision 2-pole Brushless DC-Motors are three phase slotless motors that have a wide speed and torque range and are ideal for mid- to high speed applications requiring smooth speed control, high efficiency, and long operational lifetimes.

For highly dynamic servo applications requiring very high torque in the most compact dimensions, the FAULHABER BX4 Series 4-pole, DC-Servomotors are ideal. Their robust design with very few parts and no glued components means that they are extremely durable and well suited for challenging ambient conditions such as extreme temperatures and high shock and vibration loads.

FAULHABER brushless flat DC-Micromotors are 3 phase, slotless, axial flux gap motors with a rotating back iron. They have a much higher efficiency than other flat brushless motors and their rotating back iron provides a high rotor inertia that is ideal for applications requiring low torque ripple and very precise continuous speed control. FAULHABER also offers a range of 2-pole Brushless Motors with a cylindrical rotating back iron sometimes referred to as ironless outrunner motors. What sets the FAULHABER Motor apart is the slotless design which eliminates the cogging effect. The high inertia rotor makes these motors ideal for continuous duty applications requiring very precise speed control. These motors also have on-board speed control electronics that can be configured for different speed profiles.

Digital Hall sensor output signal 2-pole motor

Sensors

FAULHABER 2-pole or 4-pole DC-Servomotors and Flat Brushless DC-Micromotors come standard with 3 discrete digital Hall sensors with a 120° phase shift.

Analog Hall sensor output signal 2-pole motor

As an option, most FAULHABER Brushless DC-Servomotors are available with analog (linear) Hall sensors.

These sensors can replace the need for a high resolution encoder in many applications and provide the basic commutation signal for the Brushless DC-Servomotors in combination with FAULHABER Motion Controllers. In some cases, for example, the FAUHABER BHx family, discrete sensors are replaced by a commutation PCB which provide the hall signals but can, in some cases, also provide sinusoidal commutation signals.

Magnets

FAULHABER Brushless DC-Servomotors are designed with a variety of different types of magnets to suit the particular performance of the given motor type or application conditions. These materials include high performance rare earth magnet types such as SmCo and NdFeB.

Service life

Due to the fact that motor commutation is achieved electronically and not mechanically, the operational lifetime of a FAULHABER Brushless DC-Servomotor depends mainly on the lifetime performance of the motor bearings. FAULHABER uses high precision preloaded ball bearings in all of its Brushless DC-Servomotors 6 mm in diameter and larger. Factors affecting the life of the motor bearings include the static and dynamic axial and radial bearing loads, the ambient thermal conditions, the motor speed, shock and vibrational loads, and the precision of the shaft coupling to the given application. If operated according to the data sheet Brushless DC-Servomotors have an operational lifetime many times that of mechanically commutated (brush) DC-Motors.

The main benefits

No cogging torque resulting in smooth positioning and speed control and higher overall efficiency than other brushless motor types
Extremely high torque and high performance in relation to the size and weight of the motor
Absolute linear relationship between load to speed, current to torque, and voltage to speed, with a highly sensitive current / torque behaviour
Extremely low torque ripple

Modifications

FAULHABER specialises in the adaptation of its standard products for customer-specific applications. Available modifi cations for FAULHABER Brushless DC-Servomotors include:

Additional voltage types
Connecting cables (PTFE and PVC) and plugs
Configurable shaft lengths and second shaft ends
Modified shaft dimensions and pinion configurations such as flats, gears, pulleys and eccenters
Extended temperature range
Vacuum compatibility (e.g. 10-5 Pa)
Modifications for high speed and / or high load applications
Modifications for high shock & vibration loads
Autoclavable Motors
Modifications for motors with tighter than standard electrical or mechanical tolerances

Product Combinations

FAULHABER offers the industry’s largest selection of complementary products tailor made for all of its Brushless DC-Servomotors including:

Precision gearheads (planetary gearheads, spur gearheads
and zero-backlash spur gearheads)
High resolution Encoders (Incremental and Absolute)
High Performance Drive Electronics (Speed Controllers,
Motion Controllers)
Integrated drive electronics (Motion and Speed Control)