255-FES72-080 — 5.5 kW 72V PMSM motor

34.5 Nm continuous at 1,600 RPM · 98.6 Nm peak · 255 frame

The 255-FES72-080 is a 5.5 kW 72 volt BLDC motor built to turn slowly and pull hard. It holds 34.5 Nm continuously at 1,600 RPM on 80 Arms, and will produce 98.6 Nm at 240 Arms — close to three times its continuous torque, from a frame weighing 32 kg.

The torque constant is what defines this machine: 0.431 Nm per amp, the highest of any winding in this group and more than twice that of a fast-wound 255. That is what lets it deliver thirty-four and a half newton-metres from only eighty amps. In practice it means the motor can often drive a load directly that would otherwise need a reduction stage — an auger, a mixer, a winch drum, a conveyor head. Taking the gearbox out removes the backlash, the oil, the noise and the service interval along with it, and the efficiency lost in reduction gearing comes back as useful output.

Running at 1,600 RPM on a ten-pole rotor puts the drive at only 133 Hz, which is undemanding for any 72 volt controller and makes this an easy motor to pair. Eighty amps continuous is equally undemanding on the battery and the cable run. The combination — high torque, low speed, low current, low drive frequency — is unusual and is the reason to choose this winding over a faster one with a gearbox in front of it.

Rotor inertia is 0.008789 kg·m², roughly twice that of the light 255 windings, so the machine resists rapid changes of speed. That is an advantage under shock loading, where the rotor carries the machine through a momentary jam rather than stalling, and a disadvantage on duty that starts and stops many times a minute. Choose it for loads that run steadily and occasionally meet resistance, not for fast indexing.