AME 11 End of Unit – SVE Study

AME 11 End of Unit Quiz

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How does hysteresis improve the performance of an On-Off control system?

C) It allows the system to adjust output continuously.

B) It prevents rapid cycling by creating a dead zone between switching on and off.

D) It enables the system to predict and correct future errors.

A) It increases the switching frequency of the system.

2 / 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.

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.

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.

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.

3 / 12

Explain dead zone in control terms.

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.

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.

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.

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.

4 / 12

Explain hysteresis in control terms.

A) Hysteresis is the phenomenon where the output of a control system depends on its past input, causing a lag or delay in response. Reason: This describes hysteresis correctly, where the system’s output is influenced by the history of inputs, leading to different responses for increasing versus decreasing inputs.

B) Hysteresis is the ability of a control system to adapt its response based on changes in input conditions. Reason: This describes adaptability rather than hysteresis, which specifically deals with lag in response due to past inputs.

D) Hysteresis is the speed at which a control system can respond to input changes. Reason: This describes response time rather than hysteresis, which involves differences in response based on input history.

C) Hysteresis is the effect of system instability caused by rapid changes in input. Reason: This describes system instability or oscillations rather than the lag or memory effect described by hysteresis.

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

C) It is more expensive than proportional control systems.

A) It requires complex programming to function.

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

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

6 / 12

Explain proportional bandwidth in control terms.

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.

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.

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.

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.

7 / 12

With reference to engine governors, explain speed droop.

B) Speed droop refers to the increase in engine speed when the governor's sensitivity is reduced. Reason: Reducing sensitivity affects response time, not speed droop.

D) Speed droop describes the governor's ability to maintain a constant engine speed despite fluctuations in ambient temperature. Reason: Speed droop is related to load changes, not temperature fluctuations.

A) Speed droop is the reduction in engine speed that occurs when the engine is subjected to an increase in load, relative to the no-load speed. Reason: Speed droop measures how much the engine speed decreases from its no-load speed when a load is applied.

C) Speed droop is the amount by which the governor’s set point changes to match variations in fuel quality. Reason: Speed droop pertains to load variations, not fuel quality.

8 / 12

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

A) Proportional band is directly proportional to gain.

D) Proportional band and gain are the same thing.

B) Proportional band is inversely proportional to gain.

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

9 / 12

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

A) The output is continuously variable.

C) The system adjusts output in small increments.

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

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

10 / 12

Explain derivative action in control terms.

B) Derivative action describes the process of integrating the accumulated error over time to adjust the control output.

D) Derivative action is the component of the control system that maintains the steady-state error by constantly adjusting the control output proportionally.

A) Derivative action involves adjusting the control output based on the rate of change of the error, aiming to predict future errors and reduce overshoot.

C) Derivative action adjusts the control output based on the proportional deviation from the setpoint, with no regard to the rate of change.

11 / 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.

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.

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.

12 / 12

Explain the purpose of Derivative Action.

C) Derivative Action adjusts the control output to maintain a constant error, ensuring that the system remains at a fixed setpoint without any fluctuations.

B) Derivative Action helps to anticipate future errors by reacting to the rate of change of the error, thereby improving the system’s stability and response time.

A) Derivative Action aims to eliminate steady-state errors by continuously adjusting the control output based on the accumulated error over time.

D) Derivative Action compensates for errors in the system by applying a proportional correction based on the current error value alone.

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