Touch Current Measurement with Single Human Body Impedance Networks and Thermal Imaging Techniques for Electric Heating Tubes Filled with Electrician Grade Magnesium Oxide Powder

摘要

A hybrid-channel touch current measurement system for an electric heating tube filled with electrician-grade oxide powder was build. The hybrid-channel system consists of a channel for weak voltage acquisition connected with a single human body impedance network and a channel for thermal image acquisition. One channel is used as the touch current measurement channel, while the other is used as the valid measurement time determination channel. The system reduces the time to test the touch current for the electric heating tube compared with the standard JB/T 8508, as the thermal image acquisition channel provides the criterion that the heating tube has already reached a steady state. The system accurately detects filling defects inside the heating tube as well. Furthermore, the system can be used as a senior standard of an electric heating tube. A comparison measurement with the touch current tester TL5802 was carried out. The results show that the proposed system reduces the test time by over 5 minutes and has much lower power consumption.