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MATERIALS HANDLING AND STORAGE |
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Overhead and Gantry Cranes - Brakes |
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Each independent hoisting unit of all cranes shall be provided with a holding
brake, applied directly to the motor shaft or some part of the gear train. All floor, remote, and pulpit-operated crane bridge drives shall be provided with a brake or non-coasting mechanical drive. Overhead or gantry cranes with a cab on the trolley shall be provided with a trolley brake. However, under most conditions, trolleys will not be required to have a brake. Some cab operators use plugging to stop the motion of the bridge if cranes are not equipped with bridge brakes. Plugging is the process of reversing the direction of the bridge motor through the controller. This can be a hazardous practice especially if it is the only method of stopping cranes because if power to the crane is lost for any reason, the crane will be unstoppable. |
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