Product Selector   Gemco 1997 Gate Hoist Lmt Swtch Gemco Stamping Press Control Gemco 1980 Micro-Adjust Cams Gemco 1980S Limit Switch Manual Gemco 2000 Rotary Limit Switches Gemco 3001 Adjustable Couplings Brake Systems Application Guide Model CB/TM Brakes Manual Model ET Shoe Brakes Manual Model H Shoe Brakes Manual Model H Brake Parts Manual   GEMCO Brake Systems Application Guide:     Index     Brake summary & key features     Typical description &        applications hydraulic brakes     Typical description &        applications electric brakes     Selecting brake torque based        on motor data     Crane hoist braking torque     Crane trolley braking torque Selecting brake size based    on load data Overhauling load torque Brake thermal capacity Overhauling loads Hydraulic brake selection for    bridge cranes Hydraulic brake torque ratings    & thermal capacities DC magnetic shoe brake torque    ratings & thermal capacities

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Brake Systems Application Guide
 

INTRODUCTION When selecting the proper brake for a specific application, there are several factors to consider; a few that need to be reviewed are brake torque, stopping time and/or deceleration rates, brake mounting, brake location, thermal rating, environment, and brake style.   The brake systems manufactured by Gemco Industrial Brake Products are external friction brakes. Applications for which these brakes are suited can be classified into two general categories: non-overhauling and overhauling.     A) Non-overhauling loads are typically horizontally moving masses such as crane bridges, crane trolleys, and horizontal conveyors.     B) Overhauling loads tend to "run up" in speed if a brake is not present, examples of which are crane hoists, winches, lifts, and downhill conveyors.   Type A (non-overhauling) loads require brake torque only to stop the load and will remain at rest due to friction. Type B (overhauling) loads have two torque requirements; the first is braking torque required to stop the load, and the second is the torque required to hold the load at rest.   SELECTING BRAKE TORQUE BASED ON MOTOR DATA The full-load torque of a motor is a function of horsepower and speed and is commonly used to determine a brake torque rating. The brake torque rating is to equal or exceed the full load torque of a motor. The formula to calculate the full load motor torque is as follows:   where: 5250 = constant   HP = motor horsepower   RPM = speed of motor shaft   S.F. = application service factor   T = static brake torque   CRANE HOIST BRAKING TORQUE Sizing of crane hoist brakes is typically based upon full load hoisting torque. The following is a brief summary of guidelines for hoist brakes.   Each hoist on a crane should be equipped with at least one spring-set magnetic brake; hoists handling hot metal should be equipped with more than one brake. Brake rating expressed as a percent of hoisting torque at the point of brake application should be no less than the following: 150% when only one brake is used.   150% when multiple brakes are used and the hoist is not used to handle hot metal. Failure of any one brake shall not reduce braking torque below 100%.   175% for hoists handling hot metal. Failure of any one brake shall not reduce brake torque below 125%.