255-AGZS72-250 — 19 kW 72V PMSM motor

94 Nm continuous at 2,000 RPM · 267 Nm peak · 255 frame

The 255-AGZS72-250 is a 19 kW 72 volt BLDC motor and the largest machine Innotec builds in the 255 frame. It holds 94 Nm continuously at 2,000 RPM on 250 Arms, and reaches 267 Nm at 750 Arms — close to three times its continuous torque, with a peak output of 53 kW.

Nineteen kilowatts continuous from a 56 kg frame is a high specific output, and it comes from running the machine at a torque constant of 0.376 Nm per amp with a rotor large enough to carry the heat. The practical consequence is that this motor competes with considerably larger lower-voltage machines on output while staying inside a 255 flange, which is what makes it useful for repowering: the mechanical interface stays the same as the smaller windings in the frame, and only the electrical side changes.

Two hundred and fifty amps continuous on a 72 volt bus is a serious but manageable figure — properly sized cable and a controller rated for sustained rather than nominal current, rather than the busbar-and-inspection regime that the same output demands at 24 volts. The 750 amp peak is the number to design the controller around, and it is worth the effort: the curve holds 267 Nm to 1,900 RPM, so the full peak is available across almost the whole working band rather than only off the line.

Rotor inertia is 0.03465 kg·m², the highest of any 255 winding. The machine is correspondingly steady under shock loading and carries momentum through a jam, but it will not suit duty that reverses or indexes many times a minute. Choose it for drives that run and pull. At 166.66 Hz the drive requirement is undemanding for a machine of this output.