The GBX0800080551F is a straight-tooth planetary gearbox from Schneider Electric's GBX series, sized for servo or stepper motor output stages where a compact 80 mm diameter and an 8:1 reduction ratio are needed. The continuous output torque is 50 N.m at 100 rpm and 30 °C; the maximum intermittent torque reaches 80 N.m under the same conditions. That 50 N.m continuous figure is the one to size against — the gearbox will hold that torque indefinitely within the 30,000-hour service life at rated speed.
Efficiency, backlash, and noise — the precision trade-offs
Rated at 94 % efficiency, the GBX0800080551F loses about 6 % of input power to friction and windage — typical for a single-stage planetary with straight teeth. The torsional backlash is 9 arcmin maximum, which sets the repeatability floor for positioning: if your axis requires less than 9 arcmin of lost motion at reversal, this gearbox will add that uncertainty. Noise output is 60 dB at 1 m, no-load — quiet enough for a lab or light assembly line, but not silent; the straight-tooth profile generates more whine than a helical planetary.
Sourcing an obsolete gearbox — lifecycle reality and supply posture
Schneider Electric lists the GBX0800080551F as obsolete. The gearbox is available through independent surplus and broker channels — quantities are lot-specific and confirmed at RFQ.
Mechanical limits — axial and radial load capacity at the output shaft
The output shaft carries a maximum axial force (Fa) of 1200 N for a 10,000-hour life at 100 rpm and 30 °C, derated to 900 N for the full 30,000-hour service life. Radial force (Fr) is 950 N for 10,000 hours, dropping to 650 N for 30,000 hours — both measured at mid-distance from the output shaft. These are the limits for overhung loads like pulleys or pinions mounted directly on the shaft; exceeding them shortens the bearing life below the 30,000-hour target.
Environmental fit — IP54, temperature range, and lubrication
The shaft output seal carries an IP54 rating — protected against dust ingress and splashing water, but not immersion or high-pressure washdown. Ambient operating temperature spans -25 °C to 90 °C. The gearbox is lubricated for life, meaning no oil-change interval in the 30,000-hour service window. Housing is black anodized aluminium; the shaft is C45 steel.