Product Description:

The U9M4HA is a brush-commutated pancake DC motor produced by Kollmorgen within the ServoDisc Pancake DC Motors series. Its printed-circuit armature removes iron teeth, giving the motor a flat profile suited for tight axial spaces while suppressing detent forces that disturb low-speed regulation. In automated machinery, the unit couples directly to light rotary loads, supplying consistent torque for indexing tables, semiconductor handlers, or optical scanners where rapid reversals and accurate velocity tracking are required.

This motor delivers a continuous stall torque of 35 N-cm, sustaining closed-loop tension or positioning without overheating. When driven at the rated speed of 3000 rpm, it draws 6.8 A; this current pairs with the torque constant of 7.17 N-cm/A to establish the continuous output curve. A terminal resistance of 1.310 Ω determines copper losses and influences drive sizing at low speeds. The back-EMF constant is 7.50 V/krpm, matching the rated voltage of 34.7 V so the drive has sufficient voltage margin for transient commands. Zero cogging torque ensures smooth motion at sub-revolution frequencies, and the motor supplies 44 N-cm at 25 °C or 40 N-cm at 40 °C, reflecting the effect of temperature on winding resistance. With a rated mechanical power of 138 W, the unit fits precision servomechanisms that need moderate power density without gear reduction.

For dynamic bursts, the armature can accept a peak torque of 395 N-cm at a momentary current of 56 A, giving machinery additional capacity for acceleration or shock loads. Operation remains linear up to a maximum recommended speed of 6000 rpm, doubling the continuous operating point while keeping commutation within the capabilities of the brushes. The flattened housing measures 111.0 mm in diameter and 60.7 mm in length, simplifying integration into disk-style stages or compact actuators without additional gearboxes.