GU-P305 Planetary Gear Unit

Three planets share the load on every stage, so torque density is the highest in the range and the reaction stays balanced on the housing rather than pushing sideways on the bearings.

How this frame is rated

The GU-P305 carries 12,000 Nm of rated output torque, calculated on tooth flank and root capacity to international gear rating standards at a service factor of 1.0. Ratios run from i 3.9 to i 500, which at 1450 rpm input puts the output shaft between 2.9 and 371.8 rpm. Motors from 4 to 110 kW bolt to the input.

With the largest listed motor the frame reaches its mechanical torque limit at about i 17.1. Below that ratio the motor governs and output torque still climbs with the reduction; above it the frame governs, and extra ratio buys you speed reduction only. That is the knee you can see on the characteristic chart further down this page.

What usually decides the selection

Thermal capacity is 88 kW of continuous throughput without auxiliary cooling at 20 °C ambient. Permissible radial force at the shaft mid-point is 62,000 N; move the load towards the shaft end and that figure falls quickly, so tell us where the pulley actually sits. Housing is Machined alloy steel, protection IP66, and the unit weighs 520 kg dry.