AME 11 End of Unit – SVE Study

AME 11 End of Unit Quiz

1 / 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.

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

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

2 / 12

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

A) It requires complex programming to function.

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.

C) It is more expensive than proportional control systems.

3 / 12

State with reasons, the type of actuator fitted to the process valves for a lubrication oil cooling system in which the valve diverts the oil through a cooler.

C) Hydraulic Actuator: Reason: Hydraulic actuators are generally used for high-force applications and may be less suitable for the precise control required in diverting oil through a cooler.

B) Pneumatic Actuator: Reason: Pneumatic actuators provide reliable and fast operation and are well-suited for applications requiring frequent adjustments to the valve position, such as diverting oil flow through a cooler.

D) Manual Actuator: Reason: Manual actuators require manual intervention to adjust the valve position, which is not ideal for automatic and precise control of oil flow through a cooler.

A) Electric Actuator: Reason: An electric actuator offers precise control of the valve position and can be easily integrated with control systems to modulate the oil flow through the cooler as required.

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.

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

5 / 12

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

B) Proportional band is inversely proportional to gain.

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.

6 / 12

With reference to engine governors, explain sensitivity.

A) Sensitivity refers to the governor's ability to maintain engine speed despite fluctuations in load conditions. Reason: A sensitive governor adjusts engine fuel input or throttle position to counteract variations in load and keep the engine speed constant.

C) Sensitivity describes how easily the governor can detect changes in ambient temperature and adjust engine speed accordingly. Reason: While temperature changes can affect engine performance, sensitivity in a governor is primarily related to its response to load changes and fuel adjustments.

D) Sensitivity indicates the level of noise produced by the governor during operation. Reason: Noise levels are not related to the sensitivity of a governor but rather to its design and operation characteristics.

B) Sensitivity refers to the governor’s response to small changes in the fuel supply, affecting the engine speed control. Reason: A sensitive governor will react quickly to minor adjustments in fuel input, thereby maintaining precise engine speed control.

7 / 12

Explain settling time in control terms.

D) Settling time is the time it takes for the system to completely stop moving after a control action has been implemented. Reason: Settling time focuses on stabilization around the set point, not complete cessation of movement.

A) Settling time is the time it takes for a system's output to initially reach its desired value after a disturbance has been applied. Reason: Settling time is concerned with the time to stabilize around the desired value, not the initial reach.

B) Settling time is the time required for the system's output to remain within a specified range around the set point after a disturbance, and it measures the time until the output stops oscillating significantly. Reason: This correctly describes settling time as the time it takes for the output to stay within a certain percentage of the set point and cease significant oscillations.

C) Settling time is the total time it takes for the system to return to its original state after a disturbance has been removed. Reason: Settling time is related to stabilization around the new set point, not returning to the original state.

8 / 12

Explain dead zone in control terms.

C) Dead zone is the amount of time it takes for the control system to start responding after a command is issued. Reason: This describes the delay or lag in response, not the concept of dead zone.

B) Dead zone is the time required for a system to stabilize after a disturbance. Reason: This describes settling time rather than dead zone, which is about the unresponsive range in the input-output relationship.

D) Dead zone is the ability of a control system to maintain output stability despite fluctuations in the input. Reason: This describes system stability rather than dead zone, which is specifically about input-output response range.

A) Dead zone refers to a range within which changes in input do not produce any change in the output of a control system. Reason: This correctly describes dead zone as a region where the system is unresponsive to inputs within that range.

9 / 12

With reference to engine governors, explain stability.

B) Stability describes the governor's capacity to change the engine speed quickly in response to sudden changes in fuel supply. Reason: Rapid response is more related to the governor's responsiveness, not its stability.

C) Stability is the measure of how much the governor's set point can drift from the desired speed due to wear and tear. Reason: Set point drift due to wear is not directly related to stability, which focuses on maintaining speed consistency.

D) Stability refers to the governor's ability to handle extreme variations in ambient temperature without affecting engine performance. Reason: While temperature variations can affect performance, stability specifically concerns speed consistency under load changes.

A) Stability refers to the governor's ability to maintain a constant engine speed without oscillations or fluctuations when subjected to varying loads. Reason: Stability in governors is about how consistently the engine speed is maintained despite changes in load or other disturbances.

10 / 12

Explain proportional bandwidth in control terms.

C) Proportional bandwidth refers to the frequency range over which the proportional controller can maintain a constant output. Reason: This describes frequency response rather than the range of input values within which proportional control is effective.

B) Proportional bandwidth is the measure of how quickly a system can respond to changes in the proportional gain setting. Reason: This describes response time rather than the range of input values for proportional action.

A) Proportional bandwidth refers to the range of input values over which the proportional control action is effective in adjusting the output of a system. Reason: This describes how the range within which proportional control can operate effectively is defined, focusing on the input values that impact the output.

D) Proportional bandwidth is the extent of variation in the system output for a given change in proportional gain. Reason: This describes the effect of changing proportional gain on output variation, rather than the range of input values affecting proportional control.

11 / 12

With reference to engine governors, explain isochronous governing.

B) Isochronous governing allows the engine speed to fluctuate slightly around the set point to accommodate load changes. Reason: This describes droop control rather than isochronous governing, where slight fluctuations are acceptable.

D) Isochronous governing is a technique where the engine speed is allowed to drift with load changes, optimizing fuel efficiency. Reason: Allowing speed drift with load changes describes a droop control system, not isochronous governing.

C) Isochronous governing adjusts the engine speed only during idle periods to maintain stability. Reason: Isochronous governing applies to all operating conditions, not just idle periods.

A) Isochronous governing ensures that the engine speed remains constant regardless of the load applied, maintaining the same speed even with varying demands. Reason: Isochronous governing is designed to keep the engine speed constant, independent of changes in load.

12 / 12

State the reasons for fitting a pneumatic process valve with a feedback positioner.

D) A feedback positioner is fitted to provide a backup control signal in case the primary control system fails, ensuring the valve remains operational.

C) A feedback positioner is fitted to reduce the overall power consumption of the valve actuator, improving energy efficiency.

B) A feedback positioner is fitted to increase the air pressure supplied to the actuator, which helps in enhancing the overall force applied to the valve.

A) A feedback positioner is fitted to monitor the valve position and provide real-time correction signals to ensure the valve remains at the desired position, improving accuracy and stability in the process control.

Your score is