Crane brakes

46 Magna 400MagnaShear motor brake employs oil shear technology to extend service life in demanding crane applications, especially those with frequent start/stop cycles. Oil shear technology transmits torque between lubricated surfaces, thereby eliminating wear on friction surfaces. A patented fluid recirculation system dissipates heat, eliminating a build-up condition identified as the most common problem in dry braking systems. Elimination of the wear significantly increases service life and virtually eliminates adjustment while elongating maintenance intervals.

MagnaShear brakes suit applications where the motor is reversed each cycle such as cranes, winches and hoists, plus loader/unloader or pallet return conveyors, and rail car spotters and dumpers. The oil shear technology provides a smooth “cushioned” stop, which reduces shock to the drive system and further extends downstream component service life. Fully enclosed, the brakes are impervious to moisture, dirt and dust common in concrete and other building materials operations. In contrast to 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, thus imparting torque to the other side. The 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 curtailed as are the need for adjustments typical in dry brakes.

The motor brakes are available to accommodate a wide range of applications, with spring set torque ratings from 3 to 1,250 ft.-lb., and can be sized to the correct torque independent of the motor frame size or horsepower. MagnaShear have “quick mount” features for attaching to drive motors in NEMA frame sizes 56 to 449, and are shipped ready to install. They are also available pre-mounted on a motor for severe duty applications. The 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. — Force Control Industries, Fairfield, Ohio, 513/868-0900;