Electrical Control Systems — Part 1 MCQs with Explanations

The position and velocity error of the type 2 system is zero and a constant value as for type 2 system velocity error is finite while acceleration error is infinite.

An open-loop system is defined by the fact that the output signal or condition is neither measured nor fed back for comparison with the input signal or system set point. Therefore open-loop systems are commonly referred to as “Non-feedback systems”.

Addition of zeros in transfer function causes lead-compensation. Lead-compensation is achieved by adding zeros to the transfer function, which advances the phase of the system and improves the transient response. In a lead-compensated system, the zero increases the system's responsiveness by increasing the phase margin, leading to a faster response. Lag-compensation and lead-lag compensation involve different configurations of poles and zeros to achieve specific performance characteristics.

Any externally introduced signal affecting the controlled output is referred to as a stimulus . In the context of control systems and feedback control, a stimulus is an external input or disturbance that can influence the behavior of the system. This stimulus can lead to changes in the system's output, and the control system aims to minimize the effects of such disturbances through feedback and control actions. The other options are related terms but do not specifically refer to externally introduced signals: Option A: feedback refers to the process of taking a portion of the output and feeding it back to the input of a system to regulate its behavior. Option C: signal is a general term for a function representing information or data, which can include control signals, stimuli, or any other data-carrying function. Option D: gain control is related to adjusting the amplification or gain of a signal within a control system but is not the term used to describe externally introduced signals. So, the correct answer is Option B: stimulus .

For an open control system, the following statements are generally true: Less expensive: Open control systems are often less expensive to implement compared to closed-loop systems. Construction is simple and maintenance easy: Open control systems are simpler in design and therefore easier to maintain. Errors are caused by disturbances: Open control systems can be affected by external disturbances as they do not have feedback to correct deviations. However, the statement that recalibration is not required for maintaining the required quality of the output is incorrect. Open control systems may still require recalibration to maintain output quality, as they lack feedback mechanisms to automatically adjust for changes and disturbances.

Zero initial condition for a system means system is at rest and no energy is stored in any of its components.

Error signal is the input to the controller and it causes the output to be the desired output.

A good control system should ideally have the following features: Good stability: Ensures that the system maintains its performance and does not exhibit excessive oscillations or instability. Good accuracy: Ensures that the system accurately follows the desired input or reference signal. Sufficient power handling capacity: Ensures that the system can handle the required load without performance degradation. However, a slow response is not desirable in a good control system. A good control system should exhibit a fast response time to quickly react to changes and provide timely corrections. Thus, Option B (slow response) is the feature that does not align with the characteristics of a good control system.

system gain is the correct answer to “With feed back _____ reduces.”. This question is standard in competitive examination syllabi for Electrical Control Systems.

Auto-pilot for an aircraft is the correct answer to “Is a closed loop system.”. This question is standard in competitive examination syllabi for Electrical Control Systems.

reduce steady state error is the correct answer to “The effect of error damping is to”. This question is standard in competitive examination syllabi for Electrical Control Systems.

increases by the sane saaaajajt as the gain decrease is the correct answer to “The band width, in a feedback amplifier.”. This question is standard in competitive examination syllabi for Electrical Control Systems.

Noise is proportional to band width is the correct answer to “Due to which of the following reasons excessive bond width in control systems should be avoided”. This question is standard in competitive examination syllabi for Electrical Control Systems.

motor-generator set is the correct answer to “Hydraulic torque transmission system is analog of”. This question is standard in competitive examination syllabi for Electrical Control Systems.

not necessarily stable is the correct answer to “If a step function is applied to the input of a system and the output remains below a certain level for all the time, the system is”. This question is standard in competitive examination syllabi for Electrical Control Systems.

All of the above is the correct answer to “On which of the following factors does the sensitivity of a closed loop system to gain changes and load disturbances depend”. This question is standard in competitive examination syllabi for Electrical Control Systems.

Eyes is the correct answer to “By which of the following the control action is determined when a man walks along a path”. This question is standard in competitive examination syllabi for Electrical Control Systems.

minimizes is the correct answer to “In a control system integral error compensation _______ steady state error”. This question is standard in competitive examination syllabi for Electrical Control Systems.

Two poles is the correct answer to “The type-2 system has ________ at the origin.”. This question is standard in competitive examination syllabi for Electrical Control Systems.

The gain of the system should be increased is the correct answer to “Which of the following should be done to make an unstable system stable”. This question is standard in competitive examination syllabi for Electrical Control Systems.

system stability is the correct answer to “With feedback _____ increases.”. This question is standard in competitive examination syllabi for Electrical Control Systems.

LVDT is the correct answer to “Which of the following is an electromagnetically device”. This question is standard in competitive examination syllabi for Electrical Control Systems.

Any of the above is the correct answer to “Which of the following can be measured by LVDT”. This question is standard in competitive examination syllabi for Electrical Control Systems.

Laplace Transform and Fourier Integral is the correct answer to “The frequency and time domain are related through which of the following”. This question is standard in competitive examination syllabi for Electrical Control Systems.

current is the correct answer to “In force-voltage analogy, velocity is analogous to”. This question is standard in competitive examination syllabi for Electrical Control Systems.

Only one of the static error co-efficients has a finite non-zero value is the correct answer to “Which of the following statements is correct for any closed loop system”. This question is standard in competitive examination syllabi for Electrical Control Systems.

The system is at rest and no energy is stored in any of its components is the correct answer to “In a system zero initial condition means that”. This question is standard in competitive examination syllabi for Electrical Control Systems.

Root locus is the correct answer to “Technique gives quick transient and stability response”. This question is standard in competitive examination syllabi for Electrical Control Systems.

Closed loop system is the correct answer to “A control system in which the control action is somehow dependent on the output is known as”. This question is standard in competitive examination syllabi for Electrical Control Systems.

Integrator is the correct answer to “Increases the steady state accuracy.”. This question is standard in competitive examination syllabi for Electrical Control Systems.

underdamped is the correct answer to “If the gain of the critical damped system is increased it will behave as”. This question is standard in competitive examination syllabi for Electrical Control Systems.

Oscillator is the correct answer to “In an automatic control system which of the following elements is not used”. This question is standard in competitive examination syllabi for Electrical Control Systems.

Needle of the speedometer is the correct answer to “A car is running at a constant speed of 50 km/h, which of the following is the feedback element for the driver”. This question is standard in competitive examination syllabi for Electrical Control Systems.

Speed is the correct answer to “Which of the following can be measured by the use of a tachogenerator”. This question is standard in competitive examination syllabi for Electrical Control Systems.

Reduced velocity lag error is the correct answer to “In a system low friction coefficient facilitates”. This question is standard in competitive examination syllabi for Electrical Control Systems.

Band width is the correct answer to “As a result of introduction of negative feedback which of the following will not decrease”. This question is standard in competitive examination syllabi for Electrical Control Systems.

State model representatives is the correct answer to “. . . . . . . . can be extended to systems which are time-varying”. This question is standard in competitive examination syllabi for Electrical Control Systems.

gear trains is the correct answer to “The term backlash is associated with”. This question is standard in competitive examination syllabi for Electrical Control Systems.

Feedback is the correct answer to “A closed loop system is distinguished from open loop system by which of the following”. This question is standard in competitive examination syllabi for Electrical Control Systems.

The output for any given input is the correct answer to “Transfer function of a system is used to calculate which of the following”. This question is standard in competitive examination syllabi for Electrical Control Systems.