| 摘要 |
A transformer (TR1) transmits a signal from an oscillator (1) via a coupler (2). It is coupled to a connceting point (7) on a medium pipe (9) with an insulation (10). Along the pipe is fitted a wire (8) which, on changes in the insulation, affects the coupler signal via the transformer. Such change is detected by a lever detector (3), whose output signal is fed as a reference to a comparator (4). At a level, dependent on the insulation resistance, an alarm is triggered. To the first transformer is linked in seriees a second one (TR2) via the wire, associated with the pipe, such that a signal portion to the coupler is picked up by a second level detector (5) whose output is fed to a second comparator (6) as a reference, for alarm triggering. The wire and pipe are galvanically separated from the rest of the measuring appts.
|
