TECH

1. Electrical Test Paper -1 Max Marks 80
Name Date
1. What do the abbreviations below mean?
(4 marks)
UPS………………………………………………………………………………………….
CB……………………………………………………………………………………………
MCB… ………………………………………………………………………………………
ELCB………………………………………………………………………………………..
A.C. ………………………………………………………………………………………..
D.C…………………………………………………………………………………………..
2. What voltage would you expect to find below (4 marks)
a) Single Phase Voltage …………………………………………………….
b) Three Phase Voltage …………………………………………………….
3. What is the function of a Transformer? (4 marks)
…………………………………………………………………………………………………………………
…………………………………………………………………………………………………………………
4. What is the function of an ELCB (4 marks)
…………………………………………………………………………………………………………………
………………………………………………………………………………………………………………..
5. Preferred location of the Transformer & Panel Room (2 marks)
Close to one another
Far off from one another

2. 6. Power in electrical circuits is expressed by the formula: (4 mark)
a. P= I² R c. P = E² I
b. EI d. P = I / E
……………………………………………………………………………………………………………..
7. What is the function of a Capacitor. (6 marks)
……………………………………………………………………………………………………………….
8. How do you locate the windings on a Star Delta Motor (4 marks)
………………………………………………………………………………………………………
………………………………………………………………………………………………………
9. How many contactors are there in Star Delta control (4 marks)
……………………………………………………………………………………………………………….
10. If you have a Short Circuit, which would trip first the ELCB (4 marks)
or the MCB?
………………………………………………………………………………………………………………..
11. What is Electricity (4 marks)
……………………………………………………………………………………………………………….
……………………………………………………………………………………………………………….
12. When checking a three phase contactor. (4 marks)
What voltage should you have?
a) Between phases. ……………………………………
b) Between Phase and Neutral. …………………………………..
c) Between Phase and Earth. ……………………………………
13. What is the correct fuse rating for a 6kw appliance? (4 marks)
…………………………………………………………………………………………………………...
14. What is an Ohm………………………………………………………………… (4 marks)

3. 15. What is a DOL Starter and what are the disadvantages (4 marks)
..............................................................................................................................................
..............................................................................................................................................
16. What is the difference between a fuse and a breaker? (6 marks)
..........................................................................................................
..........................................................................................................
17. Which device is used to store an electrical charge? (4 marks)
a) Resistor
b) Diode
c) Capacitor
d) Rectifier
18. Draw a Fluorescent Lighting Circuit. (6 marks)
19. What is the current carrying capacity of the following PVC cables?
a) 1mm (2 mark)
b) 1.5mm
c) 2.5mm
20. What is the colour coding on a three phase 4 wire system? (2 mark)

4. ANSWERS
1. Expand the abbreviations
(2 marks)
UPS……..Uninterruptible Power Supply
CB……….Circuit Breaker
MCB…….Miniature Circuit Breaker
ELCB……Earth Leakage Circuit Breaker
A.C. …….Alternating Current…..
D.C.……..Direct Current……
2. What voltage would you find: (2 marks)
a) Single Phase Voltage
240 Volts
b) Three Phase Voltage
415 Volts
3. What is the function of a Transformer? (2 marks)
A Device to magnetically step-Up, or step Down an alternating
current to a different voltage.
4. What is a clean Earth (2 marks)
Used in Computer rooms where no other equipment is connected to
Computer Room equipment.
5. Preferred to locate Transformer & Panel Room (1 mark)
Close to one another
Far off from one another
6. a. P= I² R (2 marks)
7. A coil pulls the contactor in and energises the circuits. (3 marks)
8. By using a mega and finding the pairs of windings. (2 marks)
9. 3 (2 marks)

5. 10. Carries dissipated current back to centre tap of transformer.
(2 marks)
11. No voltage on the coil or faulty coil. (2 marks)
12. a) 415 b) 230 c) 230 (2 marks)
13. 13 amps (2 marks)
14. A unit of resistance. (2 marks)
15. Direct on Line Starter. It will use a lot of electricity on start up.
(2 marks)
16. Volt Drop is caused by long runs of cable. Increase cable size.
(3 marks)
17. Capacitor. (2 marks)
18. Fluorescent lighting circuit. (3 marks)
19. (1 marks)
a) 10
b) 15
c) 20
20. Red, Blue, Yellow, Black. (1 mark)