Product Description:

The U12M4H is a permanent-magnet DC motor manufactured by Kollmorgen within the ServoDisc Pancake DC Motors series. Its flat armature topology shortens the magnetic path and lowers inertia, so the motor can drive pick-and-place heads, indexing tables, or other automation loads that require fast reversals. The 70.6 mm stack length and 139.7 mm outside diameter keep the envelope depth small, allowing the rotor to fit directly against belt pulleys or gear stages without increasing the machine footprint.

The electrical section has an armature resistance of 0.610 ohms, which limits current surge during startup, and a back EMF constant of 18.50 V/KRPM, which indicates the voltage returned to the drive at speed. Normal operation centers on a rated voltage of 62.7 V and a rated current of 7.9 A; together, these values yield 396 W of mechanical output while keeping copper losses within design limits. Torque production is represented by a torque constant of 17.68 N-cm/A, so each ampere produces nearly 18 N-cm of torque. A separate terminal resistance of 0.750 ohms accounts for brush and lead contributions, and it must be included when setting the drive’s current limit.

The motor provides a continuous stall torque of 137 N-cm, supporting static loads without exceeding thermal limits. For transient events, the armature can deliver a peak torque of 1465 N-cm, subject to magnetic saturation and commutation limits. Under rated conditions, the shaft turns at 3000 rpm, while suitable application duty cycles may permit operation up to the recommended maximum speed of 6000 rpm when bearing life and commutation arcing are properly managed. The motor sustains 126 N-cm at 25 °C and 112 N-cm at 40 °C, showing how higher ambient temperatures reduce continuous torque. Its total mass is 5.0 kg, which supports gantry mounting while providing thermal mass for steady-state heat dissipation.