120 mm frame, 25:1 planetary reducer
The Schneider Electric GBX1200250842D is a planetary gearbox in the GBX series, with a 120 mm external diameter housing and a single-stage 25:1 reduction ratio. The unit is built around straight-cut gears and ships lubed for life, so the commissioning step is a flange-and-couple rather than a fill-and-vent. Mounting orientation is unrestricted — the datasheet allows any position — which removes one of the usual panel-layout headaches when the gearbox has to share a machine base with adjacent drives or cabling runs.
Torque, efficiency, and noise — the three numbers that size the fit
Continuous output torque is rated 230 N.m and the maximum (short-duration) figure is 368 N.m, so the gearbox absorbs acceleration peaks and shock loads without slipping the service-life budget. Mechanical efficiency sits at 94 %, which is typical for a single-stage planetary and translates directly into less waste heat at the housing. No-load radiated noise is 65 dB measured at 1 m — quiet enough for cabinet-mounting near operator workstations or instrumentation, and consistent with a straight-tooth geometry rather than the louder helical class. Maximum torsional backlash is 12 arc.min and torsional rigidity is 13 N.m/arcmin — adequate for general positioning and indexing duty, though demanding servo applications will want to confirm the hysteresis against the controller's tuning window before committing the BOM line. Moment of inertia at the input is 1.49 g.cm², so the gearbox adds negligible reflected inertia to the motor side and won't distort the drive's acceleration profile in a typical servo loop.
Shaft loading envelope and the 30 000-hour service life
Service life is specified at 30000 h at 100 rpm and 30 °C ambient — that is the benchmark figure for the shaft-load ratings below, not an unconditional guarantee. The maximum axial force Fa is 2100 N over the 30000-hour envelope and rises to 2800 N if the duty is capped at 10000 h; the maximum radial force Fr is 1500 N (30000 h) or 2000 N (10000 h), both referenced to a force applied at mid-distance from the output shaft. Pick the duty row that matches the application before sizing the coupling and the bearing support. Ambient operating range is -25 °C to 90 °C and the shaft seal carries IP54, which covers indoor machinery and sheltered outdoor cabinets but is not a washdown rating — keep the unit away from direct jet impingement or food-grade cleaning cycles.