The invention relates to a turbomachinery turbine overspeed limiter. The turbine comprises a disk rotating around a longitudinal axis (AX) and a rotating blade (11),And a distributor (13) with fixed blades (12),Each rotating blade (11) comprises a free end terminated by a heel (19) carrying at least one ratchet wheel (23),Each guide vane (12) has a radial outer platform (29) through which it is connected to the crankcase component (9). Each platform (29) has an upstream end with a friction surface (36) relative to the left-handed body (23),When the turntable moves downward (AV), the left wheel (23) leans against the friction surface (36). The friction surface (36) has a radial cylindrical upstream portion which is the same as or farther from the free end of the left-handed body (23),And a tapered downstream portion inclined to the upstream (AM) direction along a longitudinal centerline (AX) away from the downstream (AV).Abstract figure: Figure 3
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