255-DZS72-100 — 7 kW 72V PMSM motor

22.1 Nm continuous at 3,300 RPM · 63 Nm peak · 255 frame

The 255-DZS72-100 is a 7 kW 72 volt BLDC motor for fast, continuous duty with real overload capacity. It holds 22.1 Nm continuously at 3,300 RPM on 100 Arms, and reaches 63 Nm at 300 Arms — nearly three times continuous, with a peak output of 20.3 kW from a 24 kg frame.

This is the higher-speed half of a winding pair. The 255-DZS72-080 produces almost the same torque — 21.3 Nm — but does it at 2,800 RPM on 80 amps; this winding gives 22.1 Nm at 3,300 RPM on 100. Half a kilowatt of extra output for a quarter more current, at essentially the same torque. Where the driven equipment is a fan, an impeller or anything whose delivered output climbs with shaft speed, that is the trade worth making, and the two share a rotor, a frame and a 24 kg weight so nothing else about the installation changes.

Twenty kilowatts of peak from a motor this size is the other reason to look at it. The ratio of peak to continuous is close to three to one, so the drive can be sized for the average load rather than the worst case, provided the controller can deliver 300 amps in short bursts. Rotor inertia is 0.005409 kg·m² — light enough to accelerate quickly, heavy enough to carry the machine through a brief jam. Torque holds flat from standstill to rated speed at every current up to 200 Arms; only the peak curve falls away before 3,300 RPM, which is why the 20.3 kW peak is reached slightly below rated speed rather than at it.

At 275 Hz rated frequency the drive requirement is high but not extreme. It is worth confirming against a candidate controller, particularly one intended for low-speed traction work.