Sie sind hier: Startseite » Technik » Brückenschaltungen

Murray Loop

Murray loop bridge is a bridge circuit used for locating faults in underground or underwater cables.[1] It has been used for more than 100 years. [2]
One end of the faulted cable is connected through a pair of resistors to the voltage source. Also a null detector is connected. The other end of the cable is shorted. The bridge is brought to balance by changing the values of RB1 and RB2, which is achieved when:

which is equivalent to:

The value of resistance Rx is proportional the length Lx, thus the location of the fault can be calculated:

where L is the total length of the cable under test - a value proportional to Rg.
The method assumes a single fault exists, of low resistance compared with the undamaged cable insulation resistance, and that the cable conductors have uniform resistance per unit length.

Referenzen

Quellnachweise:
Murray Loop Bridge, Wikipedia 2012 (Zugriff am 26.02.2012) - Lizenz entsprechend CC-BY-SA 3.0