| 摘要 |
<p>A system for monitoring abnormally high temperature along the length of a heating conductor (H) includes a tracing cable (T) containing a heating conductor (H) and a monitoring conductor (M). The monitoring conductor (M) is connected to a control circuit (C) which detects a short in the monitoring conductor (M) caused by abnormally high temperature of the heating conductor (H) to provide an alarm signal (44). The control circuit also detects an open circuit in the monitoring conductor (M) to provide a second alarm signal (42) indicative of a discontinuity in the monitoring conductor (M). The location of the abnormal temperature condition in heating conductor (H) can be determined by measuring the impedance of the monitoring cable (M) after the abnormal temperature condition has been detected by control circuit (C).</p> |
