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MagnaShear Motor Brakes & PosiTorq Winch Tension Control Brakes in the News

Maritime Activity Reports, Inc.

September 6, 2011

Oil Shear Technology Lasts Longer with Virtually No Maintenance

MagnaShear oil shear motor brakes and Positorq oil shear winch tension control brakes from Force Control Industries are ideal for marine applications because they eliminate normal maintenance and adjustment, operate smoothly, and last up to 10-times longer than standard brakes.  High grade castings, marine duty coatings, stainless steel fasteners and accessories make these brakes the ideal solution for onshore and offshore marine applications.  Their varied ship-board and in-port applications include use on anchor winches, mooring winches, drawworks, capstans, conveyors, hoists, loaders and un-loaders, and more.

Oil Shear Technology is the reason that brakes by Force Control do not need maintenance, adjustment, disc replacement, and last up to 10 times longer than standard brakes. Oil Shear Technology is the function of a boundary layer of transmission fluid in shear between the friction disc and drive plate. As the parts come together the fluid under shear will transmit torque between the two parts as well as absorb heat. This heat is then taken away from the friction surface to the housing to be dissipated.

MagnaShear Oil Shear Marine Duty Motor Brakes – Never Need Adjustment


Totally enclosed MagnaShear brakes are impervious to moisture, dirt and dust, and salt water common in marine applications.  These proven motor brakes are available to accommodate a wide range of applications.   Spring set torque ratings from 3 to 1250 foot-pounds are available.  MagnaShear® motor brakes can be sized with the correct torque independent of the motor frame size or horsepower.

MagnaShear motor brakes feature “quick mount” features for quick and easy mounting to drive motors in NEMA frame sizes 56 to 449.  They are shipped ready to install, with no assembly or adjustments required.  They are also available pre-mounted on a motor for severe duty applications.  MagnaShear® motor brakes can be furnished to fit a NEMA or IEC frame motor, as a complete motor and brake assembly, or to mount on a machine frame or other special mounting configuration. These proven motor brakes are totally enclosed from outside contaminants, with seal integrity for harsh fresh and saltwater environments.  A modular design /assembly allows for ease of servicing and maintenance.  

Positorq Oil Shear Payout Brakes – Smooth, chatter free torque for mooring, anchor winches and drawworks

Positorq absorber brakes and clutches provide simple, precise torque control over the entire speed range, even at low speed.  Operational speeds at levels down to 0 rpm are precisely controlled without chatter, stick slip or torque variation.  Torque is controlled by actuation pressure and is independent of speeds above the residual (minimum) drag torque.  Various sizes are available from 53 Ft. Lbs up to 300,000 Ft. Lbs, with continuous heat absorption capability up to 3000 thermal horsepower.  Positorq® Oil Shear brakes are ideal for tension control applications such as on anchor systems and mooring winches, drawworks, and other on-board and in-port applications requiring smooth payout control.

In this unique Oil Shear Technology design, fluid is pumped through the multiple disc stacks to provide both lubrication and heat dissipation.  Elimination of the heat improves brake consistency, while providing longer life with virtually no adjustment or disc replacement required.  Positorq brakes are quiet – noise levels of the brake system are below 65 db.  

Since the effective radius, number of discs and friction factor remains constant, the torque available is directly equivalent to the actuation pressure (air or hydraulic) furnished to the actuating piston.  With multiple braking surfaces, the Positorq® is not only compact but also low inertia.  A separate forced lube cooling system allows for a small size with high thermal capacity. Smooth, consistent actuation with low piston hysteresis is experienced by the use of Teflon liners over the O-rings to seal the non-rotating piston.  This eliminates stick slip often associated with O-ring seals.

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