Product Description:

The U9M4HA-2 is a permanent-magnet DC motor produced by Kollmorgen. It belongs to the ServoDisc Pancake DC Motors series and uses a flat armature that contributes to its compact profile. Its low rotor inertia makes the unit suitable for rapid position or speed control in pick-and-place modules, indexing tables, and other industrial automation axes that benefit from direct-coupled torque delivery.

At a rated shaft speed of 3000 rpm, this motor delivers 57 N·cm of continuous torque while drawing a steady 6.8 A from a 40.0 V supply. These operating points correspond to a mechanical output of 178 W, matching light-to-medium-duty motion tasks that require consistent torque over long cycles. The back-EMF constant is 9.24 V/krpm, allowing the drive electronics to calculate the voltage generated during deceleration. A terminal resistance of 1.310 Ω limits current at startup. With a mechanical time constant of 2.72 ms, the rotor reaches the commanded velocity quickly. The motor has an outside diameter of 111.0 mm and a length of 60.7 mm, which help minimize its polar moment. A thermal resistance of 1.30 °C/W at rated speed supports heat transfer from the winding to the surrounding air during continuous operation.

For short motion bursts, the armature can supply up to 488 N·cm of peak torque. The commutator remains stable through a maximum recommended speed of 6000 rpm, providing headroom for brief acceleration profiles. An armature resistance of 1.120 Ω provides a predictable relationship between applied voltage and current under transient conditions. The torque constant of 8.83 N·cm/A links drive current directly to output torque for feedforward control. The motor has a mass of 2.6 kg, allowing it to be mounted on small gantries or rotary stages without requiring excessive structural reinforcement.