Product Description:

The U9M4LR is a brushed DC servo motor produced by Kollmorgen for the ServoDisc Pancake DC Motors series. Its flat disc armature design suits installations where axial space is limited and fast torque response is required, including automated pick-and-place heads, vision stages, and light conveyors. The housing measures 111.0 mm in diameter and 46.7 mm in length, giving the motor a compact form that fits shallow machine assemblies. Within an industrial drive system, it converts electrical energy into 101 W of mechanical power for regulated motion in medium-duty positioning tasks. The brushed design provides direct current control through the armature, supporting responsive torque changes during acceleration, positioning, and controlled stopping.

The motor operates at a terminal voltage of 12.6 V and a rated continuous current of 15.6 A, which establish the normal electrical load on the connected drive. A torque constant of 2.32 N-cm/A links armature current to developed torque, allowing the controller to regulate output through predictable current commands. The armature resistance is 0.175 Ω, indicating low copper losses during operation. A back-EMF constant of 2.43 V/krpm indicates the voltage generated for each 1,000 rpm of shaft speed and helps account for regenerated energy during deceleration. The terminal resistance is 0.365 Ω, while the thermal resistance at rated speed is 1.30 °C/W. These values support appropriate cooling and drive selection without requiring excessive electrical or thermal capacity.

The motor provides a continuous stall torque of 25 N-cm, allowing the energized shaft to support a stationary load. Short dynamic events can use a peak torque of 315 N-cm, which corresponds to a transient current draw of 137 A. During routine operation, the shaft maintains a rated speed of 3000 rpm while delivering a rated torque of 32 N-cm. The maximum recommended speed is 6000 rpm, allowing brief higher-speed operation in processes that require faster movement. Applications must keep transient loading within the motor and drive limits to prevent excessive heating or brush wear. The broad operating range supports controlled low-speed holding, normal positioning cycles, and rapid movement between programmed positions.