Product Description:

Kollmorgen manufactures the TBMS-7646-A, a frameless permanent-magnet servo motor supplied as rotor and stator components within the TBM Frameless Motors series. After the rotor is press-fitted onto a machine shaft, the motor delivers direct-drive torque without couplings or gear reduction, a layout valued in semiconductor handlers, cobot joints, and compact indexing tables where space is limited and compliance must be minimized. Low static friction of 0.068 N-m and viscous damping of 0.0281 N-m/kRPM contribute to predictable low-speed motion.

The active diameter of the stator measures 74.68 mm, while its axial stack is only 48.51 mm. These dimensions allow the motor to nest inside lightweight mechanical structures. In continuous duty, the electromagnetic package sustains 2.18 N-m of stall torque, a level set by thermal equilibrium between copper losses and the housing’s heat path. For short transients such as acceleration or shock loading, the torque ceiling rises to 6.74 N-m until winding temperature approaches its limit. The mechanical output can be spun steadily at 1850 rpm, matching applications that need moderate speed as well as high positioning stiffness. A 36.07 mm through-bore permits passage of air lines, wiring, or payload shafts, and the 0.0000819 kg-m² rotor inertia helps the servo loop achieve fast response without excessive current demand.

Electromagnetic scaling is shown by a torque constant of 0.235 N-m/Arms, so one ampere of sinusoidal phase current produces nearly a quarter newton-meter at 20 °C. The back electromotive force rises linearly with speed at 14.2 Vrms/kRPM, a figure used by the drive to set voltage margins for field-oriented control. Nominal operation assumes a bus of 48 VDC; with the phase resistance of 0.387 Ω and inductance of 0.63 mH, the motor settles quickly after step commands. Under these conditions, it can deliver a mechanical output of 335 W while remaining within its continuous thermal envelope.