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3.1 Explain how a voltmeter and an ammeter are connected to a circuit - NSC Mechanical Technology Automotive - Question 3 - 2017 - Paper 1
Question 3
3.1 Explain how a voltmeter and an ammeter are connected to a circuit. 3.2 State FOUR uses of a multimeter. 3.3 A dry compression test on an internal combustion en... show full transcript
Worked Solution & Example Answer:3.1 Explain how a voltmeter and an ammeter are connected to a circuit - NSC Mechanical Technology Automotive - Question 3 - 2017 - Paper 1
Step 1
Explain how a voltmeter and an ammeter are connected to a circuit.
Answer
To measure electrical parameters in a circuit:
- A voltmeter is connected in parallel to the component across which the voltage is to be measured. This allows it to measure the potential difference without affecting the current through the circuit.
- An ammeter, on the other hand, is connected in series with the circuit. This is essential as it measures the current flowing through the circuit by allowing all the current to pass through it.
Step 2
State FOUR uses of a multimeter.
Answer
A multimeter is a versatile tool with several applications, including:
- Direct current measurement (DC) - To measure the flow of direct current in a circuit.
- AC measurement - To measure alternating current in AC circuits.
- Resistance measurement - To determine the resistance of circuit components.
- Diode test - To check the functionality of diodes by measuring their forward and reverse bias.
Step 3
A dry compression test on an internal combustion engine indicated a very low reading at cylinder 1. A wet compression test indicated a higher reading at cylinder 1. What conclusion can be made regarding these readings?
Answer
The results of the compression tests suggest that:
- The dry compression test indicated a low reading at cylinder 1, which typically points to issues such as worn piston rings or cracked cylinders affecting the seal within the combustion chamber.
- However, the wet compression test showed a higher reading, indicating that adding oil temporarily sealed the gaps, which implies that the piston rings are likely worn out. Therefore, the low dry reading in conjunction with the higher wet reading strongly suggests that the issue lies with the piston rings.
Step 4
Describe the purpose of the following tests: 3.4.1 Beam-bending test
Answer
A beam-bending test is designed to assess the deflection or bend of beams under load. This is crucial in determining the structural integrity and flexibility of materials used in construction, ensuring that they can withstand applied forces without failing.
Step 5
Describe the purpose of the following tests: 3.4.2 Cylinder leakage test
Answer
The purpose of a cylinder leakage test is to determine whether there are gases or air leaks from the cylinders or valves. This test helps identify issues such as worn piston rings or valve seals, which can compromise engine performance and efficiency.