AME 11 End of Unit – SVE Study

AME 11 End of Unit Quiz

1 / 12

In an On-Off control system, what happens when the controlled variable exceeds the set point?

B) The system switches off the output to bring the variable back to the set point.

A) The system modulates the output to gradually reduce the variable.

C) The system increases the output to correct the error.

D) The system remains inactive until the variable drops significantly.

2 / 12

How is the level in a water tank controlled by a float and lever proportional system?

A) The float rises with the water level, causing the lever to close a valve, stopping the inflow of water when the desired level is reached.

B) The float sinks as the water level rises, which directly activates a pump to remove excess water from the tank.

D) The lever controls the water level by switching between two fixed positions—completely open or completely closed.

C) The float rises with the water level, opening a valve to allow more water into the tank.

3 / 12

Explain proportional bandwidth in control terms.

D) Proportional bandwidth describes the extent to which the proportional controller can correct errors before reaching the maximum output.

C) Proportional bandwidth is the width of the proportional band within which the control action is active and varies linearly with the error.

B) Proportional bandwidth is the range of frequencies over which the proportional controller effectively responds to changes in the process variable.

A) Proportional bandwidth refers to the range of input values for which the proportional controller provides a linear response.

4 / 12

What happens when the flow out is increased in a system where the water tank level is controlled by a float and lever proportional system?

A) The float rises, causing the control valve to open more to increase the inflow.

D) The float drops, causing the control valve to open more to increase the inflow.

C) The float rises, causing the control valve to close, reducing the inflow.

B) The float drops, causing the control valve to close, reducing the inflow.

5 / 12

What is a potential drawback of using an On-Off control system?

C) It is more expensive than proportional control systems.

D) It consumes more energy than other types of control systems.

B) It is unable to achieve precise control, leading to oscillations around the set point.

A) It requires complex programming to function.

6 / 12

With reference to hydraulic governors fitted to alternators designed to run in parallel, explain how two generators operating in parallel are able to achieve a stable load share with a 50/50 ratio.

C) By synchronizing the generators' speed and voltage settings, and using governors with equal proportional and integral action to balance the load distribution.

A) By adjusting the governor settings to ensure each generator automatically compensates for any load imbalances and shares the load equally.

B) By using manual load distribution switches to physically adjust the load shared by each generator to achieve a 50/50 ratio.

D) By connecting each generator to separate load banks and using separate governors to adjust the load independently, thus ensuring a 50/50 ratio.

7 / 12

What is the primary characteristic of a Discontinuous (On-Off) control system?

A) The output is continuously variable.

D) The system provides proportional control based on the error magnitude.

C) The system adjusts output in small increments.

B) The output is either fully on or fully off, with no intermediate states.

8 / 12

Describe a possible effect of excessive Integral Action.

D) Excessive Integral Action can increase the system’s ability to predict future errors accurately, leading to improved overall system stability.

B) Excessive Integral Action can cause the system to oscillate or exhibit sustained oscillations around the setpoint due to an overcompensation of errors.

C) Excessive Integral Action can make the control system unresponsive to errors, resulting in a steady and stable system performance.

A) Excessive Integral Action can lead to a quick and accurate response to setpoint changes, reducing the time required to reach the target value.

9 / 12

Describe using control block diagram terms how a governor maintains the speed of a diesel engine driving a generator.

B) The governor compares the actual engine speed to the desired speed setpoint and uses a proportional-integral-derivative (PID) control block to adjust the fuel input and maintain the engine speed.

D) The governor uses a feedback loop where the actual engine speed is compared to a fixed reference value, adjusting the fuel input based on a simple on-off control block.

A) The governor adjusts the fuel input based on the difference between the desired speed setpoint and the actual engine speed (feedback), using a proportional-only control block.

C) The governor uses a manual control block to adjust the engine speed directly without feedback, ensuring the engine speed remains constant regardless of load changes.

10 / 12

With reference to hydraulic governors fitted to alternators designed to run in parallel, explain why these governors have adjustable integral action.

B) To ensure that the governor can handle variations in load and maintain stable operation by adjusting the steady-state accuracy.

A) To allow the governor to respond more quickly to sudden load changes and reduce the frequency of the alternator.

C) To increase the governor’s sensitivity to small changes in load, which improves the alternator’s synchronization with other units.

D) To prevent the governor from responding to minor fluctuations in the load, reducing wear and tear on the governor mechanism.

11 / 12

With reference to engine governors, explain hunting.

A) Hunting is the term used to describe a governor's inability to maintain a constant engine speed due to excessive fluctuation in engine speed around a set point. Reason: Hunting occurs when the governor repeatedly overshoots and undershoots the target speed, causing erratic engine performance.

B) Hunting refers to the governor’s ability to detect and compensate for sudden changes in load quickly. Reason: Quick load compensation is not referred to as hunting but rather as a desirable feature in governors.

D) Hunting is the term used for a governor’s ability to remain unaffected by variations in fuel quality. Reason: Fuel quality variations impact engine performance but are not described as hunting.

C) Hunting describes the process of adjusting the governor's sensitivity to improve engine speed stability. Reason: Adjusting sensitivity is related to tuning, not hunting, which involves excessive fluctuation in engine speed.

12 / 12

What is the relationship between proportional band and gain in a control system?

A) Proportional band is directly proportional to gain.

C) Proportional band and gain are independent of each other.

D) Proportional band and gain are the same thing.

B) Proportional band is inversely proportional to gain.

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