Torque and speed — 4:1 reduction, 155 N.m continuous
The GBX1200040701F: This planetary gearbox delivers a 4:1 reduction ratio, stepping motor speed down and torque up by that factor. Continuous output torque is 155 N.m (1371.9 lbf.in) at 100 rpm and 86 °F (30 °C), with a maximum output torque of 248 N.m (2195.0 lbf.in) under the same conditions — the 60 % headroom above continuous covers acceleration peaks and short-duration overloads. The 94 % efficiency means 6 % of input power is lost as heat in the gear mesh and bearings — a figure that holds near the rated load and speed. At lower loads the percentage loss rises because the no-load friction and churning losses become a larger fraction of the total input.
Backlash and rigidity — 8 arc.min maximum, 12 N.m/arcmin
Maximum torsional backlash is 8 arc.min — the angular play between input and output when the direction reverses. For positioning axes this sets the repeatability floor; a 4:1 gearbox with 8 arc.min backlash translates to roughly 2 arc.min at the output shaft, which is standard for commercial planetary gearboxes without a preloaded or dual-pinion design. Torsional rigidity is 12 N.m/arcmin — the stiffness of the gear train under load. At the continuous torque of 155 N.m the wind-up is about 13 arc.min (155 ÷ 12), which adds to the backlash when the load reverses under torque. This matters for servo applications where the combined lost motion must stay within the axis tolerance budget.
Bearing loads and service life — 30000 h at rated conditions
Service life is 30000 hours at 100 rpm and 30 °C ambient — roughly 3.4 years of continuous operation. The gearbox is lubricated for life, so no maintenance interval for oil changes; the life limit is bearing and gear wear. Maximum axial force Fa is 2100 N at 100 rpm for the 30000-hour life, rising to 2800 N if the application accepts a 10000-hour life. Maximum radial force Fr (applied at mid-span of the output shaft) is 1500 N for 30000 hours, 2000 N for 10000 hours. These are the load limits the output bearings can sustain — exceeding them shortens life or causes premature failure.
Sourcing — obsolete, quoted to order
Schneider Electric lists the GBX1200040701F as obsolete. The gearbox is available through independent surplus and broker channels; quantities are lot-specific and confirmed at RFQ. For a replacement in an active design, a parametric search for a planetary gearbox with 120 mm diameter, 4:1 ratio, and 155 N.m continuous torque in the same mounting footprint is the starting point. The IP54 shaft output and straight-teeth geometry should be matched to avoid interface or noise issues.