To achieve the highest performance in positioning systems, the entire linear actuator structure must be optimized to result in the highest possible natural frequency, and the entire servo system design must be optimized to achieve the highest possible closed loop bandwidth. The designer of a linear motor actuator should therefore be aware of various design considerations, which are somewhat different than traditional servo system practices.

• Very high magnetic attraction (up to 10 times drive force) can exist between the motor parts. This requires careful handling of the magnetic plates, before and during installation, proper installation tools, and design for ease of disassembly in the field

• Linear bearings must be selected to support both the moving load and the magnetic attraction force. Desirable bearing characteristics include high stiffness (for increased natural frequency) and low friction. Because linear motors can provide higher velocities, the speed and acceleration limitations of the bearings need to be considered

• Metal chips must be kept outside the magnet assembly by proper seals and bellows. This is needed to prevent machine chips from penetrating the small air gap between the motor parts

• The motor air gap must be maintained within specified tolerance for proper motor functioning. The machine bearings and linear guide-way must be of sufficient precision to maintain the air gap

• Brush-less linear motors typically have moving cables. Provision must be provided in the machine to carry the cables. Motors with cooled coils will also have moving air or liquid coolant lines

• If a liquid cooled motor is selected, the coolant should include a rust inhibitor additive. The over-temperature thermistor should be connected to a safety interlock circuit in the amplifier control system to prevent overheating.

• When used in a vertical application, linear motors typically require a brake mechanism to prevent the load from dropping in the event of a power interruption

• The forcer should be mounted as close as possible to the center of mass of the moving load. The position feedback linear encoder should be mounted as close as possible to the working point of the machine. If the forcerand feedback are far apart, the machine structure and bearings must be of sufficient stiffness to minimize dynamic deflections of the structure

• Cables should be made in a twisted pair configuration, shielded and grounded properly to the machine base, servo amplifier and motor to reduce RFI. Cables should be selected for proper flex life at the designed bend radius

• Brush-less linear motors require commutation for proper operation. IntelLiDrives amplifiers support sinusoidal commutation method for motor optimal performance