a)In a 3-phase 4-wire circuit, a circuit breaker is selected to protect the circuit whose highest fault level is 6.6 MVA. Determine the required minimum breaking capacity in kA. (Note: Covert 3-phase power in terms of kA to find answer.) b)Using the below, determine the required minimum making capacity in kA as a “peak value”. Rate breaking capacity (Icn) ka: Icn<= 1.5 Factor = 1.41 1.5
16591. A 380 / 220 V r.m.s. 3-phase 4-wire circuit carries loads of 8 + j8.1 ohm; 4 + j4.1 ohm; and 2 +j2.1 ohmin the three phases respectively. The length of the circuit is 100 m, and the resistivity of the phase conductors is 0.0005 Ω/m. The neutral conductor is of the same size as the phase conductors. a) Select a reference angle 0for the first phase. Then write down the three phase voltages in both polar format and complex number format. b) Make appropriate assumptions, and take temperature effects on resistance is insignificant. Calculate the currents in the three phases. (Note: Determine conductor resistance, and apply Kirchhoff’s Voltage Law) Based on the result, suggest a main switch rating for the circuit. c) Show your preferred direction of neutral current in a diagram, and then determine its value. (Note: Apply superposition principle, and Kirchhoff’s Current Law) Use its magnitude to show that in this circuit, the unbalanced load may increase the voltage drop in some of the phases. (Note: Also observe the common volt drip in neutral) State your assumptions, if there are any. d) Suddenly the neutral wire of the circuit is broken. Estimate the new currents in the first phase, i.e. Phase L1. State your assumptions, if there are any.
1977what is the most permissible winding temp when we conducting a generator load test?(condition no load)
1678how i define power factor when some one ask me ,,,,,what is power factor ,,,,,pleas define it simple. (pleas dont use these worlds ,,the difrence bitween apparent power and actual power is power facter )
1 2236i have 500 amp inductive load of motors ,,,pleas tell me how can i calculate for capacitor bank for improving my power factor to 99 .....calcullations for capacitor bank,,,,
1572Post New Electrical Engineering Questions
why the neutral line is not giving shock to us if we touch it ?
why capacitive load is not used in routine life????any reason is there ??????
what will be happen if earth point is being used for as a neutral point for raw power , and same will be used for ups earthing
How the frame size of a flange mounted AC induction motor is calculated?
Sir, My doubt on cable sizing calculation, Load:74 KW calculated cable 1 run 50mm2. Now client asking us to reduce cable size by increasing runs. Sir, My question now when my mind strikes with 2 options 1) Divide load 74/2 = 36 and calculate cable for 36+36 making it 2 runs or 2) Simply i can divide 50mm2 /2 ie. 2 runs of 25mm2 Please suggest me sir
what is the voltage regulation for unity and zero power factor?
what is the defination of Cable database? What are the points are considered while preparing cable database? Is there any sample available for cable database?
Explain about technical and non technical losses in distribution system?
to vary valtage from 0 - max a variac is necessary . so how to design for high power applications nearly about 200KW power
please forward me the type of questions which would rise while me attending to 33KV Electrical License to my mail ID:vadrevu_raghava@yahoo.co.in
What is meant by impedance? difference between high & low impedance ?
An ISP is granted a block of addresses starting with 150.80.0.0/16. The ISP wants to distribute these blocks to 2600 customers as follows. a) 200 medium size businesses; each needs 16 addresses b) 400 small businesses; each needs 8 addresses c) 2000 households; each needs 4 addresses Design the subblocks and give the slash notation for each subblock. Find out how many addresses are still available after these allocations.
what is the use of the puls transformer in UPS & how it works???????????
y we use neutral,all r told its used to for closed path..k its a just used to closed path,in a transmission line y we put same conductor used n both phase and neutral..if we use less than phase conductor in neutral mean we ll reduce cost its right r wrong..if we use mean any problem occur in transmission line..
How to calculate loses in transformer of 160 KVA ?