Product Description:

The B-204-A-21-S is a brushless servo motor produced by Kollmorgen and supplied in the Kollmorgen Goldline B and BH Motors series. This permanent-magnet unit converts three-phase drive current into controlled rotary motion for positioning, tensioning, or velocity-regulated tasks on automated lines. By integrating a skewed lamination stack with Hall and resolver feedback options, the motor delivers smooth torque production suited for conveyors, gantry axes, and material-handling systems that demand fast settling and minimal cogging.

The electromagnetic ratings describe continuous operating capability. A continuous stall torque of 4.47 N-m is generated when the winding temperature is at its limit while the shaft is motionless, and that value is sustained by a continuous stall current of 2.9 Arms. Torque per ampere is given by a torque constant of 1.66 N-m/Arms, which provides a direct current-to-torque conversion factor for drive setup. At speed, the back electromotive force rises at 100.5 Vrms/kRPM, so the DC bus must be sized to keep regenerative voltage within insulation limits. During rated operation, the shaft supplies 4.42 N-m of dynamic torque, while phase resistance is 9.46 Ω, phase inductance is 133 mH, and viscous damping is 0.009 N-m/kRPM.

The remaining values describe the motor's mechanical response and thermal behavior. A peak stall torque of 12.8 N-m is available for rapid indexing before drive current limits are reached. The rotor inertia of 0.000173 kg-m² supports quick acceleration without sacrificing stability in high-bandwidth applications. Heat developed in the copper windings passes through a thermal resistance of 0.74 °C/W, and the thermal time constant of 21 min provides a predictable temperature rise curve for intermittent duty cycles. Overall package weight is 6.2 kg, and the four-pole design supports 440 W of mechanical power during operation.