Instrument Trade Theory N3 — Document

August 2019 — N3 — Instrument Trade Theory

N3 2019 Nated Engineering

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🎯 100 marks ⏱️ 3h 📄 8 pages 📝 43 items found

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Q1— Section header —

1.10\ in the ANSWER BOOK.

1.1A body that absorbs all the radiation falling upon radiates energy at all wavelengths of the spectrum at maximum rate. Stefan Boltzmann's law Provost' theory of heat exchange Black body condition Pyrometry theory

1.2

1.3action is defined as the action of a controller where the output signal is changed at a rate depending on the size of the measured deviation. Proportional Derivative Integral OFF control

1.4

1.5Which type of pyrometer does not require an operator to balance the instrument in order to record the temperatures? Disappearing filament optical pyrometer Wedge type disappearing

1.6

1.7

1.8

1.9

1.1010

Q2— Section header —

2.10\ in the ANSWER BOOK. COLUMN A COLUMN B

2.10The time it takes for the proportional action to repeat the derivative action The resistance of a conduct or is changed when an external stress is applied An opposition to the generation of magnetic fields

Q3— Section header —

3.1Load cells are commonly used to determine the level of solid substances or for the weighing of material in a storage bin or tanks.

3.1.1What type of strain gauge is load cell? (1\

3.1.2Make a neat, labelled sketch to show how load cells are used to measure the mass of solid substances in storage tanks. (5\

3.1.3Briefly discuss the principle of operation of load cells as shown in the sketch

Q3— Section header —

3.2Explain the term piezo electric effect (2\

3.3Make a neat, labelled sketch of linear variable differential transformer. (6\ [20]20

Q4— Section header —

4.1resistance thermometer is an instrument which measures resistance but is calibrated in temperature units.

4.1.1Make a neat, labelled sketch of this type of thermometer. (6\

4.1.2Explain the principle of this type of thermometer. (4\

4.2The resistance of a resistance thermometer is [20]20

Q5— Section header —

5.1What is the pneumatic standard output the following in South Africa

5.1.1ero

5.1.2ull range (2 (2\

5.2Make a neat label ed sketch of a flapper nozzle system with feedback (6\

5.3Make a neat, labelled sketch of a current telemetering system and explain its principle of operation. (10\

5.4State TWO defects of the system mentioned in

Q5— Section header —

Q6— Section header —

6.1A closed loop system, also known as a feedback control system uses the concept of an open oop system as its forward path but has one or more feedback loops between its output and its input.

6.1.1Draw neat, labelled block diagram of a closed loop system. (7\

6.1.2Explain the princ iple of operation of the closed loop system mentioned in QUESTION

6.1.1(4\

6.2Make a neat, labelled sketch of proportional force balance pneumatic controller. (7\

6.3Name TWO actions that valve plugs are commonly designed for. (2\ [20] TOTAL SECTION B: GRAND TOTAL:20

Mark Allocation

Total100 marks

Sections10 + 10 + 20 + 20 + 20 + 20 = 100 marks

Paper information

TitleDocument

SubjectInstrument Trade Theory

LevelN3

Document typeQuestion paper

Year2019

MonthAugust

Pages8

Downloads3

Examination context

Decade2010s

Years ago7y

SeasonWinter (SH)

Start dayThursday

Exam periodAugust 2019

Days since exam2,627

About Instrument Trade Theory examination preparation

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How to use this resource for revision

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A practical revision approach

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