What the 20:1 ratio and 120 N.m torque mean for a machine build
The GBX0800200552F is a straight-tooth planetary gearbox with a 20:1 reduction ratio, meaning the input speed is divided by 20 while the output torque is multiplied by the same factor, minus the 94% efficiency loss. The continuous output torque is 120 N.m at 100 rpm and 30 °C — this is the working limit for sizing the downstream shaft and coupling, not the peak transient rating. Maximum output torque hits 192 N.m at the same speed and temperature, but that's the short-term overload ceiling — the gearset lives at 120 N.m continuous for the rated 30,000-hour service life.
Backlash, noise, and where this gearbox fits on a real line
Maximum torsional backlash is 14 arc.min — that's standard precision for a straight-tooth planetary, not a zero-backlash servo gearhead. It works for indexing conveyors, rotary tables, and positioning axes where the load doesn't reverse under high torque or need sub-arcminute repeatability. Noise level is 60 dB at 1 m under no-load — quiet enough to mount near operator stations without acoustic enclosures. The black anodised aluminium housing and C45 steel output shaft are standard industrial build; the shaft output seal carries IP54, so it handles dry indoor environments but not washdown.
Sourcing an obsolete gearbox — what to expect
Schneider Electric lists the GBX0800200552F as obsolete — no longer in active factory production. The 80 mm frame diameter and 20:1 ratio are the critical fit dimensions — confirm the input shaft diameter and mounting pattern against your existing bracket before committing.
Bearing loads and remaining life — what a used pull tells you
Maximum axial force (Fa) is 1200 N at 100 rpm for 10,000 hours, dropping to 900 N for the full 30,000-hour service life. Maximum radial force (Fr) at mid-span on the output shaft is 950 N for 10,000 hours or 650 N for 30,000 hours. These are the limits for overhung sprockets, pulleys, or pinions — exceed them and the output bearing life collapses before the gear teeth wear. The gearbox is lubricated for life — no oil changes, no breather. Torsional rigidity is 6.5 N.m/arcmin, which means the output shaft twists about 0.15 arcmin per N.m of applied torque; that windup matters in position-loop applications but is negligible for speed-controlled conveyors.