12:1 planetary gearbox — what it delivers on a motion axis
The GBX0800120553F is a straight-tooth planetary gearbox from Schneider's GBX series, 80 mm housing diameter, with a 12:1 reduction ratio. It's sized for servo or stepper motor output stages where you need torque multiplication in a compact inline package — think indexing tables, pick-and-place axes, or conveyor drives. Efficiency sits at 94 %, so about 6 % of the input power dissipates as heat inside the housing. In a sealed, lubricated-for-life gearbox, that thermal load stays contained — no oil changes, but the ambient temperature range of -25 to 90 °C sets the operating envelope.
Torque, backlash, and stiffness — the real selection numbers
Maximum torsional backlash is 14 arcmin — this is the lost motion under reversing loads. For positioning axes that need better than 0.2° repeatability, that's a budget item; for simple speed-reduction or constant-direction drives, it's invisible. Torsional rigidity is 6.5 N.m/arcmin — meaning the gearbox twists about 0.15 arcmin per N.m of applied torque. This stiffness determines how much windup the axis sees before the load moves, critical in high-gain servo loops. Axial force limit on the output shaft is 1200 N at 100 rpm for 10,000 hours, dropping to 900 N for the full 30,000-hour service life. Radial force at mid-span is 950 N for 10,000 hours, 650 N for 30,000 hours. Overhung loads from belt drives or pinions need to stay under these numbers or bearing life shortens.
Obsolete — sourcing the GBX0800120553F today
Schneider lists this gearbox as obsolete. No direct successor order code is published — the GBX series has been superseded by newer planetary families with different frame sizes and mounting interfaces. For a line-down replacement or BOM freeze, the remaining channel is independent surplus and new-old-stock inventory. If you're evaluating a substitution, the critical fit dimensions are the 80 mm housing diameter, the 12:1 ratio, the output shaft keyway and pilot, and the input pattern matching your motor flange.
Environmental and mechanical build
Housing is black anodized aluminium — corrosion-resistant, thermally conductive, and lighter than cast iron. The output shaft is C45 carbon steel, hardened and ground. Shaft output seal is rated IP54, so it handles splash and dust in dry indoor environments but not washdown or submersion. Noise level is 60 dB at 1 m, no-load — roughly the sound of a quiet office. Under load the noise rises with torque and speed, but the straight-tooth profile is inherently noisier than helical; if acoustic specs are tight, factor in enclosure damping. Service life is rated 30,000 hours at 100 rpm and 30 °C ambient, lubricated for life — no maintenance access ports. If the duty cycle runs the gearbox near peak torque or above 30 °C, derate the service interval accordingly.