MagnaShear motor brakes for cranes

Words: Jimmy AdamidisThe MagnaShear motor brake from Force Control Industries uses oil shear technology, providing long service life, even in applications like the frequent start/stop cycles seen on cranes, hoists, winches, and other overhead material handling equipment.

The oil shear technology transmits torque between lubricated surfaces, thereby eliminating wear on friction surfaces. A patented fluid recirculation system dissipates heat, which eliminates heat build-up — the most common problem in dry braking systems. Elimination of the wear increases service life and eliminates adjustment, which also elongates maintenance intervals. An anodizing plant cut preventative maintenance by two hours per week and eliminated $8,000 in annual parts expenditures by switching from dry brakes to MagnaShear motor brakes, says Force Control. They are ideal for applications where the motor is reversed each cycle such as cranes, winches and hoists as well as loader/unloader conveyors, rail car spotters and dumpers, ship and rail car loading conveyors, trippers and pallet return conveyors.

The oil shear technology also provides a smooth, cushioned stop that reduces shock to the drive system, further extending service life of downstream components. The totally enclosed MagnaShear brakes are impervious to moisture, dirt and dust common in concrete block plants as well as asphalt shingle manufacturing, coal, bulk materials handling and forest products manufacturing.

How oil shear works

Unlike dry brakes, oil shear technology includes a layer of automatic transmission fluid between the brake disc and the drive plate. As the fluid is compressed, the fluid molecules shear, imparting torque to the other side. This torque transmission causes the stationary surface to turn, bringing it up to the same relative speed as the moving surface. Since most of the work is done by the fluid particles in shear, wear is virtually eliminated. Elimination of wear also eliminates the need for adjustments. In addition to transmitting torque, a fluid recirculation system helps to dissipate heat.

Motor sizes

The motor brakes are available to accommodate a wide range of applications. Spring set torque ratings from three to 1,250 foot-pounds are available. MagnaShear motor brakes can be sized to 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, and are 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. The motor brakes are totally enclosed from outside contaminants, with seal integrity for harsh and washdown environments. A modular design/assembly allows for ease of servicing and maintenance.

For additional information, visit www.forcecontrol.com.
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