|The variable nature of the deposit at this quarry near Garforth means great fluctuations in the loading on one key conveyor. Periodically, when the feed
material comprised a high percentage of fines, the conveyor carrying the minus 40mm product would overload and eventually trip out. The resulting digging out operation was time consuming, difficult and potentially hazardous.
The solution lay in a current monitoring relay – an electrical device that measures and monitors the electrical circuit loading being drawn by the drive motor on the problem conveyor. It can be set to initiate a cut-off on other upstream circuitries, in sequence, so curtailing the flow of materials onto the overloaded conveyor. The conveyor thus runs to clear all the materials on it before the operator re-starts the primary feeder.