32:1 planetary reduction — what the torque numbers mean
The GBX1200321402F is a 120 mm diameter planetary gearbox with a 32:1 reduction ratio. That ratio drops a 3000 rpm input motor to about 94 rpm output — typical for indexing conveyors, rotary tables, or positioning axes where you need high torque at low speed without a belt stage. Continuous output torque is 260 N.m at 100 rpm, 30 °C ambient — that is the number for sizing the gearbox into a duty cycle, not the peak figure. Maximum output torque hits 416 N.m at the same speed, but that is for intermittent overloads, not sustained running. The 94 % efficiency means about 6 % of input power turns into heat inside the housing. For a 260 N.m output at 100 rpm (roughly 2.7 kW mechanical), the thermal loss is around 170 W — the black anodized aluminium housing sinks that without forced cooling in most panel-mount or foot-mount installations.
Service life, backlash, and the real-world limits
Rated service life is 30000 hours at 100 rpm and 30 °C — that is about 3.4 years of continuous running. The gearbox is lubricated for life, so no oil-change interval to schedule. Maximum torsional backlash is 12 arc.min — standard precision for a straight-tooth planetary. If your application needs less than 6 arc.min for servo positioning, this box is not the fit; look at a low-backlash or helical planetary instead. Axial and radial load limits are speed-dependent: at 100 rpm, maximum axial force Fa is 2100 N for the full 30000-hour life, or 2800 N if you accept a 10000-hour service life. Radial force Fr at mid-span on the output shaft is 1500 N for 30000 hours, 2000 N for 10000 hours. These are bearing-life limits — overshoot them and the gearbox seizes well before the 30000-hour mark.
Obsolete — sourcing reality for the GBX1200321402F
Sourced through independent distribution against an RFQ. The 120 mm frame size and 32:1 ratio are common enough that a functional cross to a BONFIGLIOLI or SEW-EURODRIVE planetary is possible, but that requires a full interface check (input flange, shaft diameter, keyway, pilot diameter).