Electric shock-proof alarming system of crane based on field measurement

This system was a vemote monitoring alarm brake device against electric shock. The device could be widely used in a variety of crane equipments. This system consisted of two parts:detector module and receiver module. Through simple and reliable measuring methods,the detector module transformed high-voltage field strong signals into voltage signals,which were more easily to process. After being magnified,shaped and filtered,the voltage signals could produce DC signals of corresponding electric field strength. Using the high efficiency SoC C8051F020 to do the AD transform,the device sent the information to the receiver module installed in the tractor cab through wireless transceiver. The receiver module of the device could receive signals from several inductive probes. The inductive probes should be installed on the protruding points of the hoisting machinery. The receiver module analyzed and processed all the data received and displayed the results on LCD panel using red,yellow and green rectangular pattern. The pattern could show the distance between protruding points and field source visually. Once the distance between the protruding points and the surrouding charged object less than a safe distance,the device would give out a warning signal while the control relay will switch off the power to forcibly stop the operation,thus provided reliable security for working labor. The detecting module adopted effective shielding measures. Experiment results indicated that the system functions normally in the High-voltage Electric Field ranging from 30KV to 220KV.