LMBR - DC Brushed Linear Servo Motor

April 7, 2011

The brushed linear servo motor is designed for long stroke servo applications. It is ideal for direct linear motion without mechanical linkages in closed-loop position packages.

The moving permanent magnet brush commutated DC linear motor consists of a stationary primary and a moving secondary. The stationary primary is a steel laminated core, with multiple coils inserted into insulated slots. The ends of each coil are connected to a commutator bar that is mounted on an aluminum angle.

The moving secondary features multiple permanent magnets and brushes for commutation. A cable supplies power to the moving secondary. Mounting holes are located on both the primary and secondary.

The magnetic-attractive force between the primary and secondary can be used as a magnetic preload for the bearing system. The customer-supplied bearing system must maintain an air gap of 0.064 cm [0.025 inch] between the primary and secondary. The brush linear motor is available in different cross sections to meet different force requirements.

  • High forces to 1070 N [171 Lbs.]
  • High acceleration to 49 m/s/s [5g’s]
  • High speeds to 3.8 m/s [75 in/sec]
  • High accuracy 8.3 µm/m [±0.0001 in/ft] (encoder dependent)
  • High repeatability 1 µm [0.00004 in] (encoder dependent)
  • Stroke lengths to 3.2m [11 ft.]
  • Multiple moving magnet assemblies with overlapping trajectories
  • Self-commutation enables the use of low-cost brush-type amplifiers.
  • Relatively low cost per pound of thrust compared to brushless linear motors
  • Use with PWM brush-type servo control (refer to Baldor’s DC Controls – LD Series)