32:1 planetary reduction, 260 N.m continuous — what the ratings mean
The GBX1200320704F is a straight-tooth planetary gearbox from Schneider's GBX series, 120 mm diameter, delivering a 32:1 reduction ratio. The continuous output torque is 260 N.m at 100 rpm and 30 °C, with a maximum intermittent torque of 416 N.m at the same speed — the ceiling before mechanical overload. Efficiency is listed at 94 %, which is typical for a single-stage planetary set with straight teeth — the remaining 6 % is heat dissipated in the gear mesh and bearings. The 30000-hour service life at rated load (100 rpm, 30 °C) assumes the input speed and torque stay within the continuous envelope; exceeding the maximum axial force of 2100 N or radial force of 1500 N at the output shaft will shorten that life. Maximum torsional backlash is 12 arcmin — this defines the lost motion between input and output when reversing direction. For positioning applications that need better than 0.2° repeatability, a lower-backlash gearbox (e.g. a precision planetary with 3-5 arcmin) would be a tighter fit.
Sourcing a discontinued planetary gearbox
This unit is sourced through independent surplus and overstock channels. Availability is lot-specific; quantities and condition (typically new-in-box, sealed) are confirmed at RFQ. The lubricated-for-life design means no oil-change schedule to verify on a stored unit — the grease charge is sealed for the service life. For a BOM that needs a drop-in replacement, the 120 mm diameter, 32:1 ratio, and 260 N.m continuous torque are the binding dimensions — any substitute must match the output shaft interface and mounting flange pattern. No pin-compatible alternative from the same family is documented.
Installation constraints — IP54, shaft loads, and ambient range
Shaft output protection is IP54 — the gearbox body is sealed against dust ingress and splashing water at the output shaft, but not submersion or high-pressure washdown. The housing is black anodized aluminium; the shaft is C45 carbon steel. Maximum axial force on the output shaft is 2100 N for the full 30000-hour life, or 2800 N if you accept a 10000-hour service interval. Radial force limits are 1500 N (30000 h) and 2000 N (10000 h), measured at mid-span on the output shaft at 100 rpm. Overhung loads from a belt drive or pinion must stay within these envelopes to avoid bearing fatigue. Ambient operating range is -25 to 90 °C — the grease and seals handle the cold end; the upper limit keeps the internal temperature below the lubricant degradation point. Noise at 1 m, no-load, is 65 dB — a moderate level for a planetary gearbox of this size.