A Varley Bridge is connected to a faulty three-core copper cable by two identical copper leads of…

March 19, 2023/in Nursing paper help /by admin

A Varley Bridge is connected to a faulty three-core copper cable by two identical copper leads of resistance R1.
(a) Show that for the initial reading (connection to earth);
Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â 2Rx = 2Rc – RiÂ Â Â Â Â Â
(b) By multiplying the rhs brackets and collecting terms, show the effect of the leads is given by:
Rx = (Rf-Ri/Rf) Rc-(RiRi/Rf)
(c) Determine the distance to the fault by modifying the expression in (b) and using Rx/Rc = x/LÂ
(d) UsingÂ R = Î¡L/A
(e) Determine the distance to a fault on a 200 m, 120 mm2 copper cable if copper 10 mm2 test leads of length 10 m are used and Ri/Rf = 0.2.