Elect Installation & Maintenance Work 2, WASSCE (SC), 2018

Question 4

 

  1. The diagram below shows a circuit consisting of a lamp controlled by three in dependent switches.

    (i)  Using the diagram, complete the table below.


    Switch position

     

    Circuit condition

    Lamp condition

    SW1

    SW2

    SW3

    Up

    Up

    Up

     

     

    Up

    Up

    Down

     

     

    Up

    Down

    Up

     

     

    Up

    Down

    Down

     

     

    Down

    Up

    Up

     

     

    Down

    Up

    Down

     

     

    Down

    Down

    Up

     

     

     

    (ii) State one precaution to be taken while carrying out the installation in 4(a)(i).

     

    (b) The diagram below illustrates a major equipment used in an electrical workshop. Study the diagram and answer the questions that follow.

(i)    Identify the equipment.
  (ii)  Name the parts labelled I to V.
 (iii)  State one function of the part labelled III.

(iv)  State three precautions to be taken while using the equipment during installation


Observation

 

In part (a), performance was below average as many candidates failed to get the last three operations right. Candidates response to this question shows that they were confuse.

In part (b), Most candidates labelled the part correctly. Few candidates failed the labelled part III which is trigger switch or power switch.

The expected answers include:

4 (ai)              


Switch Position

Circuit condition

Lamp condition

SW1

SW2

SW3

Up

Up

Up

Close [1]

ON [1]

Up

Up

Down

Open [1]

OFF [1]

Up

Down

Up

Open [1]

OFF [1]

Up

Down

Down

Close [1]

ON  [1]

Down

Up

Up

Open [1]

OFF [1]

Down

Up

Down

Close [1]

ON [1]

Down

Down

Up

Close [1]

ON [1]

 

(ii)       One Precaution to be Taken While Carrying out Installation in 4 (a)(i)

    • Ensure that all connections are mechanically sound
    • Ensure that there is no exposed conducting parts
    • Ensure electrical continuity
    • Ensure usage of correct tools for the installation
    • Observe colour coding

(bi)      (Hand) drilling machine                                                                                            
(ii) i  -     drill bit 
ii    -     chuck         
iii    -     trigger
iv   -    forward and reverse switch                                                   
v    -    grip/handle                                                                            

(iii)      One Function of the Part Labelled III
The part labelled III is used for switching ON and OFF the machine         

(iv)      One Precaution to be Taken While Carrying out Installation in 4 (a)(i)          

    • Remove chuck keys from drills prior to use
    • Hold tools firmly and maintain good balance
    • Secure the work in a holding device not in your hands
Put on your safety wear while operating the equipment