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LI-SSB Brakes & Custom Reducers for Drilling Rig Drawworks
A major drawworks OEM needed reliable powertrain components for a new series of gear-driven
AC drawworks used on land-based drilling rigs. The units are designed for operational efficiency
with less weight, a compact footprint and reduced noise and vibration. The drawworks is a winch
that raises and lowers the drill head as sections of pipe are added during the drilling operation.
The OEM contacted Wichita Clutch, based on previous successful collaborations. After careful
review of the application, the Wichita team configured a 36" low inertia spring set brake (LI-SSB)
with a torque capacity of 840,100 lb.in. (94,916 Nm) @ 75 PSI to provide smooth, controlled
(fail-safe) emergency stops without damaging the drawworks. The self-aligning, air-released
LI-SSB is designed to handle the extreme heat typically generated during an e-stop and features
an integrated wear sensor and a custom shrink fit hub.
During the initial planning meeting with Wichita Clutch, the OEM was pleased to realize that
they could conveniently source the required gearboxes from Nuttall Gear, another Altra Industrial
Motion brand. The OEM was aware of Nuttall’s reputation for quality and reliability based on a
10-year history of supplying custom gearboxes to other leading drawworks manufacturers.
Nuttall Gear engineers worked closely with the OEM during the development and definition
of the gearbox duty cycle. The new self-aligning gearboxes needed to be shaft-mounted for
a more compact footprint. Ultimately, Nuttall manufactured custom gearboxes with an input
rating of 1500 HP @ 800/2400 RPM and a 10:1 reduction ratio. Units featured a self-contained
lubrication system which provided pressurized oil to the bearings, fabricated steel housing and
provisions for a heater in cold environments.
‘Fail-to-safety’ design for
high cyclic and general
stopping and holding duties
features through hardened
gearing, pressurized oil to
the bearings, and a
fabricated steel housing