In electrical engineering, the power factor of an AC electrical power system is defined as the ratio of the real power flowing to the load to the apparent power in the circuit ” R/Z”.
According to the Norton theorem, to find the Norton current, first remove the load resistance RL from the network terminals AB. Short circuit the terminals AB as shown in Figure calculate the current ISc or IN through the short circuit. Now resistance of 150Ω will not show any effect in the circuit. So only resistance of 30Ω will be effective. Norton current IN = 360/30 IN = 12 A
Galvanized steel conductors do not corrode, and possess high resistance. Hence such Wires are used in telecommunications circuits, earth wires, guard wire, stray wire, etc.
Isolator or disconnecting Switch: An isolator is a switch that is designed to open a circuit under no-load condition. Its main purpose is to isolate one portion of the circuit from the other and is not allowed to be opened while current is flowing in the line. Such switches are used on both sides of a circuit breaker so that its repair works or replacement could be done. Note that an isolator is never opened until the circuit breaker in the circuit is opened and it is closed before the circuit breaker is closed. If an isolator is switched OFF when a high current is flowing through the circuit, a heavy spark will be produced. This heavy spark may break the supporting insulator of the isolator which may cause a fatal accident to the operator.
The total number of the conductor in stranded cable is given by N = 3x2 − 3x + 1 Where x = no. of layer For layer 1 N1 = 3(1)2 − 3(1) + 1 N1 = 1 For layer 2 N2 = 3(2)2 − 3(2) + 1 N2 = 7 In layer 2 no. of conductor = N2 − N1 = 7 − 1 = 6 For layer 3 N3 = 3(3)2 − 3(3) + 1 N3 = 19 In layer 3 no. of conductor = N3 − N2 = 19 − 7 = 12
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