Download 2365 612 electrical sciences Exam 2025 with Answers. and more Exams Electrical and Electronics Engineering in PDF only on Docsity!
2365 612 electrical sciences Exam 2025
with Answers.
- Power generated at - Correct Answer ✅✅ >>25kv
- Power transmitted at - Correct Answer ✅✅ >>Stepped up from 25kv into 275/400kv and 132kv
- Power distributed at - Correct Answer ✅✅ >>33/11kV and 230/400v
- How are transformers kept cool - Correct Answer ✅✅ >>Air, oil or gas
- MCB type B, C, D - Correct Answer ✅✅ >>BSEN 60898
- RCD - Correct Answer ✅✅ >>BSEN 61008
- Power factor - Correct Answer ✅✅ >>The ratio of true power to apparent power. A better factor means current use age is reduced so a smaller cable size can be used and lower demand needed
- Pf - Correct Answer ✅✅ >>True power (kW) % Apparent power (kVA)
- How to create a leading power factor - Correct Answer ✅✅ >>To correct a lagging power factor we can use a capacitor (bulk and load connection) or a synchronous motor
10.Inductance - Correct Answer ✅✅ >>
how easily a certain material will induce an electromotive force (emf) within a circuit. AC makes it flux any times a second so producing inductive reactance
11.Inductive Reactance (Xl) - Correct Answer ✅✅ >> The opposition to current of AC caused by inductance of a circuit, expressed in ohms. 2pieFL Pie=3.14 f=frequency l=inductance
12.Impedance z - Correct Answer ✅✅ >>Z = square root of Rsquared + XLsquared
13.Capictors - Correct Answer ✅✅ >>Charge like batteries in AC so produces opposition to current called capacitive reactance (XC)
14.Capacitive reactance XC - Correct Answer ✅✅ >>
1% 2pieFC Pie=3.14 F is frequency C is capacitance
15.Total reactance - Correct Answer ✅✅ >> XL -XC or XC - XL XC capacitive reactance XL inductive reactance
16.Impedance (z) - Correct Answer ✅✅ >> Z= square root of rsquared+xsqaufed Impedance the opposition to current in AC comprising of resistance, inductive and capacitive reactance.
25.Star connection formula - Correct Answer ✅✅ >>Iline = Iphase Vline = Square root of 3 x Vphase
26.Delta connection formula - Correct Answer ✅✅ >>
Vline = Vphase Iline = square root of 3 x Iphase
27.Water heater explained (instantaneous) - Correct Answer ✅✅ >>Pull double pole switch which allows current to flow into little boiler in shower which instantly heats water
28.Immersion heater (stored hot water) - Correct Answer ✅✅ >>Heating element activated and heats water storing it keeping it hot and ready. Fed from own circuit with heat resistant flex and connected into FCU
29.Storage heaters - Correct Answer ✅✅ >>Used over night to gradually release heat through vents
30.MCB tripping types - Correct Answer ✅✅ >>
Thermal tripping for overload, bi metal strips warmed until current exceeds it and trips. Magnetic tripping for short circuit which automatically trips when activated.
31.Bi metal strip for mcb materials - Correct Answer ✅✅ >>Brass and steel
32.RCD trips - Correct Answer ✅✅ >>
For earth trips as rcd monitors line and neutral current for inbalances. Also has trip test button
33.Impedance (Z) - Correct Answer ✅✅ >>Total opposition (resistance and reactance and impedance) of a circuit to AC current flow, measured in ohms.
