Question 1

Plunger-type voltage testers are high-impedance devices and require several milliamperes to operate.

Accepted Answer

Plunger-type voltage testers are actually low-impedance devices and require very little current to operate. It is important to note that using a high-impedance device, such as a digital multimeter, is safer when testing for voltage as it minimizes the risk of electric shock. Plunger-type voltage testers are actually low-impedance devices and require very little current to operate. A high-impedance device would draw very little current and would not be suitable for voltage testing.

Question 2

As a generally rule, it is easier to progress backward though the circuit until the problem is identified.

Accepted Answer

It is generally easier to identify problems by testing backward through the circuit, starting from the output, and working towards the input until the issue or fault is located. It is easier to identify the problem by tracing back through the circuit since earlier stages may affect later stages.

Question 3

Overload relays are intended to disconnect the motor from the power line in the event____________ .

Accepted Answer

Overload relays are designed to disconnect the motor from the power line when the current draw becomes excessive, which can indicate the motor is experiencing too much load or there is a fault in the system. The other choices are not the primary function of overload relays. Overload relays are designed to protect motors from damage caused by excessive current draw. If the current draw becomes excessive, the overload relay will trip and disconnect the motor from the power line. Options A, B, and D are not valid reasons for overload relay operation.

Question 4

Bimetal strip type overload relays can often be adjusted for a higher setting to offset the problem of___________ .

Accepted Answer

Bimetal strip type overload relays use a bimetallic strip to sense the heat generated by the current flowing through the motor. As the ambient temperature increases, the bimetal strip may become more sensitive and trip the overload relay at a lower current level. By adjusting the setting of the relay to a higher value, the problem of tripping at a lower current level due to increased ambient temperature can be offset. Therefore, the correct choice is B, ambient temperature. Bimetal strip type overload relays are sensitive to changes in ambient temperature, which can cause the relay to trip prematurely or not trip at all when needed. By adjusting the relay for a higher setting, it can handle higher temperatures without tripping, solving the problem of ambient temperature affecting the relay's performance.

Question 5

It is often necessary to troubleshoot a circuit with power applied to the circuit.

Accepted Answer

Troubleshooting a circuit while it is powered on can help identify which components are functioning properly and which are not. However, precautions must be taken to avoid injury or damage to the circuit. Troubleshooting a circuit often involves testing voltage or current levels, which requires power to be applied to the circuit. However, it is important to take appropriate safety precautions and use proper testing equipment to avoid electric shock or damage to the circuit.

Question 6

The total or applied voltage in a series circuit must _______________the sum of the voltage drops across each component.

Accepted Answer

According to Kirchhoff's Voltage Law (KVL), the total voltage in a series circuit must be equal to the sum of the voltage drops across each component. This is because there is only one path for the current to flow through in a series circuit, and the voltage drops across each component add up to the total voltage applied to the circuit. In a series circuit, the same current flows through each component, so the sum of the voltage drops across each component must equal the total voltage applied to the circuit. This is in accordance with Kirchhoff's voltage law.

Question 7

When using an ohmmeter, make certain that the power is connected to the circuit.

Accepted Answer

When using an ohmmeter, the power should be disconnected from the circuit to avoid damage to the meter and the circuit itself. When using an ohmmeter, the power should be disconnected from the circuit to avoid any potential damage to the meter or harm to the user.

Question 8

It is virtually impossible to troubleshoot a circuit without a working knowledge of schematics.

Accepted Answer

Schematics are graphical representations of a circuit's components and their interconnections, which provide information on how the circuit works. In order to troubleshoot a circuit, one must be able to understand and analyze the information presented in a schematic. Schematics provide a visual representation of the circuit and its components, allowing troubleshooting and analysis of electrical problems. Without this knowledge, it would be difficult to diagnose issues effectively.

Question 9

A good way to disconnect the power in most control circuits is to remove the___________ .

Accepted Answer

Removing the control transformer fuse is a safe and effective way to disconnect power in most control circuits. This will ensure that power is completely disconnected and no electrical energy is present in the circuit. Removing the motor from the line or autotransformers from the line are not reliable ways to disconnect power in all control circuits. Braking pressure smoothly is not related to disconnecting power in control circuits. Removing the control transformer fuse is the best way to disconnect the power in most control circuits. This effectively cuts off power to the entire control circuit, ensuring that no electrical signals are being sent to any components.

Question 10

The voltmeter indicates the amount of potential between two points in much the same way a(n) ________.

Accepted Answer

A voltmeter measures potential difference (voltage) between two points, similar to how a pressure gauge measures pressure difference between two points.

Quiz 60: Troubleshooting Techniques