ELECTRICAL APPLIANCE SERVICEPERSON (QUALIFIED) EXAMINATION 18 November 2017 QUESTION AND ANSWER BOOKLET

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1 Candidate Code No. EASQ 3017 For Board Use Only Result Date Int Result Date Int ELECTRICAL APPLIANCE SERVICEPERSON (QUALIFIED) EXAMINATION 18 November 2017 QUESTION AND ANSWER BOOKLET INSTRUCTIONS READ CAREFULLY Time Allowed: 2 Hours You have 10 minutes to read this paper but do not start writing until instructed to do so by the supervisor. Write your Candidate Code Number in the box provided above. Your name must NOT appear anywhere in this paper. Answer all questions. The pass mark for this examination is 60 marks. Use a pen for written answers. Do not use a pencil or a red pen. Drawing instruments and pencils may be used when diagrams are required. Marks are allocated based on correctness. Do not use correcting fluid or correcting tape. It is recommended that the reference source for your answers be included in the space provided if a question can be answered from the Act, Regulations, Standard or Code. However, just stating a reference only will earn no marks. For calculation questions all workings, including formulae, must be shown to gain full marks. You will need to use the following documents in this examination: The Electricity (Safety) Regulations 2010 reprint dated 4 April AS/NZS 3760: 2010 PLEASE HAND THIS PAPER TO THE SUPERVISOR BEFORE LEAVING THE ROOM

2 Question 1 Each part in this question is worth 2 marks. Write the identifying number, 1 or 2 or 3 or 4, for each part in the box provided (a) A 230V heater comprises two elements of the same resistance connected in parallel across the supply. If one element becomes open-circuited, the power consumed by the heater is: 1. The same 2. Doubled 3. 0 W 4. Halved (b) State the reason why a 230V bayonet cap adaptor must not be used to supply a 2 kw, Class II electrical appliance. 1. Insufficient current rating 2. It is the wrong colour coding 3. It has no earthing facility 4. The cord supplying the adaptor is the wrong shape (c) A 240V/230V volt electric hair dryer is rated at 1500 W when operating at 240 V. What current will be drawn when the hair dryer is operating at 230V? A A 3. 6 A A EASQ 3017 QUESTIONS 18 NOVEMBER

3 Question 1 continued (d) Which type of switch has a bi-metal strip that heats up and controls load by switching on and off on a time basis. 1. A three-heat switch 2. A simmerstat (energy controller) 3. A thermostat 4. A stop button (e) Which of the following earth continuity test results will permit a 230V, Class I electrical appliance to be returned to service Ω 2. 1 MΩ Ω Ω (f) Which of the following switches would be used in a single-phase, splitphase motor to open the start winding? 1. A three-heat switch 2. A simmerstat (energy controller) 3. A thermostat 4. A centrifugal switch EASQ 3017 QUESTIONS 18 NOVEMBER

4 Question 1 continued (g) The reason why only one portable electrical appliance is used from an isolating transformer is to: 1. Prevent transformer overloading. 2. Minimise the problem of excessive voltage drop. 3. Prevent polarity interchange. 4. Minimise the possibility of electric shock. (h) When a three-heat switch that controls a 230V electric blanket is in the low position, two elements are connected in series across the supply. If one element becomes open-circuited, what is the voltage across the other element: 1. 0V V V V (i) The reason for carrying out an earth continuity test on a Class I electrical appliance is to: 1. Verify that the resistance is low enough to ensure that the electrical appliance will function correctly 2. Verify that the resistance is low enough to ensure protection will operate under fault conditions 3. Verify that the resistance does not exceed 1 MΩ 4. Verify that the insulation of current carrying components can withstand the maximum load current EASQ 3017 QUESTIONS 18 NOVEMBER

5 Question 1 continued (j) Which of the following voltage ranges defines standard low voltage in a multiple-phase MEN system in accordance with the Electricity (Safety) Regulations 2010? volts AC between phases volts AC between neutral and earth volts AC between phase and neutral volts AC between phase and neutral EASQ 3017 QUESTIONS 18 NOVEMBER

6 Question 2 (a) New flexible cords are being connected to two, 230V Class II, plug-in electrical appliances. (i) Appliance 1 Refer to AS/NZS 3760 and state ONE set of colours and polarity for the flexible cord conductors. Ref:. (ii) Appliance 2 Refer to AS/NZS 3760 and state ONE set of colours and polarity for the flexible cord conductors that are different from Appliance 1. Ref:. (b) A three-core extension cord is supplying a 230V, 2 kw electrical appliance. The extension cord has been disconnected because it started to overheat. State the action which will stop this situation re-occurring. EASQ 3017 QUESTIONS 18 NOVEMBER

7 Question 2 continued (c) If the phrase it is the maximum current that it is designed to carry safely is used in respect to a flexible cord, what characteristic is being described? (1 mark) (d) The figure below represents the terminals of an appliance plug after the cover has been removed. Indicate on the figure the active (phase), neutral and earth terminals. Note: You must state the polarity accurately. (3 marks) EASQ 3017 QUESTIONS 18 NOVEMBER

8 Question 3 Introduction This diagram shows the circuit for a 240V/230V fixed-wired electrical appliance. Switch Fuse P R1 R2 R3 N The 3 elements are in separate compartments. R1 R2 R Ω 52.9 Ω Ω Use the information in the introduction to this question to answer parts 3(a), 3(b) and 3(c) (a) Calculate the total current drawn by the appliance when all switches are in the on position and the appliance is operating at 230V. (6 marks) EASQ 3017 QUESTIONS 18 NOVEMBER

9 Question 3 continued (b) Calculate the total power consumed by the appliance when all switches are in the on position and the appliance is operating at 230V. (c) Calculate the power consumed by element R3 when the appliance is operating at 230V. EASQ 3017 QUESTIONS 18 NOVEMBER

10 Question 4 AS/NZS 3760 details two instrument tests for testing the insulation of a single-phase, Class I plug-in electrical appliance that has been repaired. (a) Test 1 Name of test: (1 mark) Ref. Instrument used: (1 mark) How the test is carried out: Test result: (1 mark) Ref. EASQ 3017 QUESTIONS 18 NOVEMBER

11 Question 4 continued (b) Test 2 Name of test: (1 mark) Ref. Instrument used: (1 mark) How the test is carried out: Test result: (1 mark) Ref. EASQ 3017 QUESTIONS 18 NOVEMBER

12 Question 5 Introduction A 230V final subcircuit supplies three socket outlets. Electrical appliances are being used from the socket outlets. The final subcircuit is protected by a 20A MCB. The MCB has tripped. When the MCB is reset, it trips again when the supply is restored to the circuit. The fault is one of the following: The MCB is overloaded. A phase to neutral short-circuit in an electrical appliance A phase to earth fault in an electrical appliance Use the information in the introduction to this question to answer parts 5(a), 5(b) and 5(c). (a) The MCB is overloaded (i) Describe how to determine that this is the fault (ii) State how this fault can be remedied. (1 mark) EASQ 3017 QUESTIONS 18 NOVEMBER

13 Question 5 (b) A phase to neutral short-circuit in an electrical appliance (i) Describe how to determine that this is the fault (ii) State how this fault can be remedied. (1½ marks) EASQ 3017 QUESTIONS 18 NOVEMBER

14 Question 5 (c) A phase to earth fault in an electrical appliance (i) Describe how to determine that this is the fault. (ii) State how this fault can be remedied. (1½ marks) EASQ 3017 QUESTIONS 18 NOVEMBER

15 Question 6 (a) (i) Draw and label a circuit diagram of a single-phase capacitor-start motor. (3 marks) (ii) Describe how to reverse the direction of rotation in a single-phase capacitor-start motor. (1 mark) (iii) How is the start winding in a single-phase capacitor-start motor disconnected when the motor is up to speed? (1 mark) EASQ 3017 QUESTIONS 18 NOVEMBER

16 Question 6 continued (iv) What would be the effect on the performance of a single-phase capacitor-start motor if the capacitor had become disconnected and the motor was switched on whilst connected to a load? State ONE reason to support your answer. (b) (i) Describe how the direction of rotation can be reversed for a universal motor (1 mark) (ii) State TWO typical applications for a universal motor (1) (2) EASQ 3017 QUESTIONS 18 NOVEMBER

17 Question 7 Use the Electricity (Safety) Regulations 2010 to answer parts 7(a), 7(b), 7(c) and 7(d). (a) Define the term personal protective equipment. Ref: (b) State TWO situations where an electrical appliance is deemed electrically unsafe. (4 marks) (1) (2) Ref: EASQ 3017 QUESTIONS 18 NOVEMBER

18 Question 7 continued (c) State TWO methods of connection for the supply of electricity to hand-held appliances. (1) (2) Ref: (d) State ONE safety system that must be used when operating a 230V, Class I, handheld electrical appliance in a situation that is normally damp. EASQ 3017 QUESTIONS 18 NOVEMBER

19 Question 8 (a) State ONE reason why danger tags are used. (b) Two registered electrical appliance service persons are carrying out electrical repairs on the same 230V, fixed-wired, industrial machine. State TWO precautions that must be taken when attaching danger tags to an isolating switch of the industrial machine. (1) (2) (c) State ONE situation in which a danger tag can be removed. EASQ 3017 QUESTIONS 18 NOVEMBER

20 Question 8 continued (d) State ONE reason why an out-of-service tag is attached to electrical equipment. (e) A voltage test is being carried out at the supply side of a single-phase isolating switch to establish if a fixed-wired Class I appliance is isolated. Between which terminals of the isolating switch would testing be carried out to clearly establish that isolation (or otherwise) has taken place. EASQ 3017 QUESTIONS 18 NOVEMBER

21 Question 9 (a) Instrument tests are being carried out on a 230V, Class I electrical appliance. (i) State ONE reason why an earth continuity test is carried out. (ii) State ONE reason why a polarity test is carried out (iii) State ONE reason why an insulation resistance test is carried out. EASQ 3017 QUESTIONS 18 NOVEMBER

22 Question 9 continued (b) A polarity test is carried out on a Class I, portable, electrical appliance after it has been repaired and the flexible cord replaced. The appliance is controlled by a single-pole switch. Detail the THREE important points this polarity test will confirm. (4 marks) (1) (2) (3) EASQ 3017 QUESTIONS 18 NOVEMBER

23 For Candidate s Use For Examiner s Use Only Questions Answered Marks In the box, write the number of EXTRA sheets you have used. Write NIL if you have not used any TOTAL EASQ 3017 QUESTIONS 18 NOVEMBER