Electrical Technology Memo 1 (English)

November 2016 — Grade 12 / Matric — Electrical Technology

Memo 2016 Grade 12 English

↓ Download PDF 📄 457.2 KB View Exam Paper

Preparing document

📋 Document Analysis

🎯 200 marks 📄 13 pages 📝 88 items found ∑ 1 math symbols 📚 2 topics

See full analysis

Questions — A Preview of What to Expect in the Document

This section provides a quick preview of questions from the document. It may not display every question or the complete wording of each one. For the full content, including diagrams, tables and other information, view the original PDF above.

2.1All calculations must show the formulae.

2.2Substitution of values must be done correctly.

2.3All answers MUST contain the correct unit to be considered.

2.4Alternative methods must be considered, provided that the correct answer is obtained.

2.5Where an incorrect answer could be carried over to the next step, the first answer will be deemed incorrect. However, should the incorrect answer be carried over correctly, the marker has to re calculate the values, using the incorrect answer from the first

Q1— Section header —

1.1Working on a live system with exposed conductors Working with portable electric equipment that is not insulated correctly. Using electrical machines without using the required safety equipment or clothing.

1.2The incorrect use of etching acid and other chemicals. The unsafe use of power tools Not using guards and goggles

1.3Good attendance Respect for fellow workers Respect for seniors Respect for work environment

1.4Remove the person from the heat source Remove any burnt clothing if not stuck to the victim Run cool water on the burnt area; do not use ice or grease.

1.5Proper ventilation is essential to keep people working efficiently the use of chemicals can make people drowsy and create an unsafe condition. (2\

1.6Involve the workers Identify hazards Record your findings Consider good practice in your industry (2\ [10]10

Q2— Section header —

2.1NOTE If the candidate indicates , award 2 marks (2\

2.2NOTE: mark Drawing phasor diagram mark = Labelling the phases mark = Labelling the angle between the phases Markers may consider rotation

2.3.130,39 (3\

2.3.230,39 cos Alternative Method (3\

2.4The function of a kWh meter is to measure the amount of energy power consumed by a consumer over a period of time. Alternative To measure energy. (2\

2.5Adding power factor correcting capacitors in parallel with the load Use synchronous motors. (2\

2.6.1in (3\

2.6.2Only two watt meters are required instead of three The power of balanced and unbalanced load may be measured The power factor of a balanced load can be determined. (2\ [20]20

Q3— Section header —

3.1sulation purposes ooling purposes (2\

3.2Copper losses Iron losses Dielectric losses Stray losses

3.3an be connected in delta to deliver power to transmission lines Can be connected in star to deliver power to consumers Delivers more power for the same size Can deliver both

3.4A transformer cannot step up power because all transformers have internal losses that will reduce the output power. In an ideal transformer input and output power is the same.

3.5If the load of the transformer is increased the transformer will draw more power from the supply to deliver the increased load. As the voltage is constant the primary current will increase. (3\

3.61,75 6600 20000

3.6(3\

3.6219,39 6600 PH(S\ PH(P\ (3\ [20]20

Q4— Section header —

4.1.1There is no connection The connection is magnetic and not electrical by nature (1\

4.1.2A three phase voltage supply is connected across the stator windings. This sets up three phase currents flowing in the stator windings. The currents create rotating magnetic field in the stator. The rotating magnetic

4.1.3The motor will still rotate but would not develop the correct torque (output power\. NOTE: This question may have different interpretations.

4.2They require less maintenance as they do not have as many parts as a single phase motor For the same size frame as a single phase motor they deliver a higher torque. (2\

4.3To determine that the integrity of the insulation is sound so that the motor may be energi without an electrical fault occurring. (3\

4.4Check for secure mountings. Check for cracked frame. Check smooth rotation (1\

4.5.1r/min 1000 (3\

4.5.21000 r/min (3\ NOTE: The answers are rounded off as the answers are given in r/min Learners must be given credit whether they have or haven t rounded off.

4.6.15,59 (3\

4.6.24,25 0,95 cos (3\

4.7The overload unit relay offers protection to the motor and operator under fault conditions. When activated it will remove power from the main contactor disabling the circuit. (3\

4.8.1Conveyor belt tart the first drive motor and after pre etermined time start the second drive motor

4.8.2If the contacts were faulty when the start button is depressed the contactor MC would energi e motor 1. When the star t button

4.8.3When N/O S tart button is pressed, coil MC energises, thus starting motor 1. Subsequently the contact N/O

5.1Reactance is the opposition offered to the flow of current in an AC circuit by either a capacitor or an inductor or both . Impedance is the opposition offered to the flow of current in an AC circuit

5.2The phase angle indicates the angle between the supply voltage the current this indicates the power factor of the circuit (2\

5.3.1Point A indicates the resonant frequency of the graph. At resonance it can be seen that X The effect of and X are opposites resulting in reactance being zero at resonance. As a result thereof Z R at resonance.

5.3.271,18 (3\

5.4.136,05 (40 (3\

5.4.233,68 36,05 cos cos (3\

5.554,13 1,47 NOTE: This is a complex calculation and is rated as a higher order, difficult question. [20]20

Q6— Section header —

6.1Ladder diagrams Function block diagram Sequential flow chart Instruction list

6.2Sensing device Switches Pushbuttons Limit switches Pressure switches (any two\ (2\

6.3Hardwire system would use many relays, cam controllers, timers, and counters. Control panels would have to be re wired when production models were changed. Hardwired system physically take up more space than PLC systems

6.4A low current device can be activated by connecting it via the PLC output relay to a source Transistor output PLC s can be connected directly as it delivers an output voltage via a transistor.

6.5NOTE Please take note of the mark allocation indicated for grouping. Be aware of the alternative method of populating the Karnaugh map when labelling is different. (11\

6.6(5\

6.7(1\

6.7A.B (1\

6.7A.B (2\

6.8.1Normally open contact / switch Input Input (1\

6.8.2Normally closed contact Input Inverted input (1\

6.8.3Coil output Output (1\ 11

6.9.1Alternative circuit using NON Inverted inputs are acceptable. Note: One mark may be awarded for a correct drawing with NO labels.

6.9.2Motor tarter (1\ [40]40

Q7— Section header —

7.1Open loop voltage gain is infinite Input impedance is Infinite Output impedance is zero Infinite bandwidth (3\

7.2Unconditional stability means that the operation of the amplifier is not influenced by temperature changes. (2\

7.3Positive feedback occurs in an amplifier circuit when a portion of the output signal is fed back into the input. The portion of the wave fed back will be in phase with the input therefore added to the input waveform.

7.4Oscillator circuit. (1\

7.5The bandwidth increased. The level of noise (hiss\ decreased The gain is predictable The deformation of the input signal is reduced (2\

7.6(3\ MC1N/O+V-V0 VMC1 N/O 12

7.7.1Inverting op amp (1\

7.7.2

7.7.312000 (3\

7.7.4(3\

7.7.5was decreased the voltage gain of the op amp will decrease as it is directly proportional the value of the feedback resistor. (2\

7.8.1This circuit allows for various input signal voltages to be fed into the circuit thus producing a single output signal

7.8.2(3\ 13

7.9.1Timing circuit (1\

7.9.2(7\ Note: Labelling of T1 and T2 is not critical. If only T1 or is labelled, award 2 marks.

7.9.312000 (3\

7.10(3\

7.11The differentiator is one type of op amp where the magnitude of the output is determined by the rate at which the voltage applied to its input changes. The

7.12amps are packaged as an integrated circuit in a hard plastic body with external pins for connections into circuits amps may also be packed in an SMD package. (2\ [50] TOTAL Trigger pulse50

Mathematical Content

trig

Topics Identified

CircuitsMachines

Mark Allocation

Total200 marks

Sections10 + 20 + 20 + 40 + 20 + 40 + 50 = 200 marks

Paper information

SubjectElectrical Technology

Year2016

SessionNovember

TypeMemo

PaperPaper 1

LanguageEnglish

Pages13

Downloads2

Examination context

Decade2010s

Years ago10y

SeasonSpring (SH)

Start daySaturday

Exam periodNovember 2016

Days since exam3,640

About Electrical Technology examination preparation

This Grade 12 examination resource can be used as part of a structured revision programme. Past papers are most useful when learners attempt questions independently, work within a realistic time limit, and review their answers afterwards.

How to use this resource for revision

A past examination paper is most useful when it is treated as an active revision exercise. Try the questions yourself before checking the corresponding memorandum. Where you make an error, identify the reason — was it a knowledge gap, a calculation mistake, an interpretation issue, or an examination technique problem?

For stronger examination practice, complete the paper without unnecessary interruptions and keep track of the questions that take the most time. Afterwards, review the memorandum and separate knowledge gaps from mistakes caused by interpretation, calculation, structure, or examination technique.

understanding question requirements

applying subject knowledge

working under time constraints

checking answers

identifying revision priorities

A practical revision approach

Start by completing the resource without looking at the memorandum. Review incorrect and incomplete answers afterwards and make a short revision list based on the areas that caused difficulty.

Grade 12 subject hubs

Each matric subject has its own dedicated hub on Freemode with every past paper and marking memorandum we have archived for that subject.

➗ Mathematics View papers → 📊 Mathematical Literacy View papers → ⚗️ Physical Sciences View papers → 🧬 Life Sciences View papers → 📒 Accounting View papers → 💼 Business Studies View papers → 📈 Economics View papers → 🌍 Geography View papers → 🏛️ History View papers → 📖 English View papers → 🇿🇦 Afrikaans View papers → 🗣️ IsiNdebele View papers → 🗣️ IsiXhosa View papers → 🗣️ IsiZulu View papers → 🗣️ Sepedi View papers → 🗣️ Sesotho View papers → 🗣️ Setswana View papers → 🌾 Agricultural Sciences View papers →

Corresponding examination paper

Examination paper available

Open the corresponding examination paper to practise the questions before reviewing the marking memorandum on this page. Attempt every question under timed conditions for the most realistic preparation.

Electrical Technology Paper 1 (English) →

File details

File size457.2 KB

Pages13

Archived on7 September 2026

File age46d

ContributorFreeMode

Fingerprint2C1B09B0668C

Questions and learner discussion

No questions or discussions have been posted yet.