70 + Interview Questions in Control System and Components in Control Systems Page 2 InterviewSolution

51.	A stepper motor having a resolution of 300 steps/rev and running at 2400 rpm has a pulse rate of- pps.(a) 4000(b) 8000(c) 6000(d) 10,000This question was posed to me during an internship interview.The above asked question is from Stepper Motors topic in section Control System and Components of Control Systems
Answer» The correct CHOICE is (c) 6000 Explanation: PULSE PER SECOND is mathematically given as PPS = (Rpm/60)*(NUMBER of steps per minute).

Discussion

52.	Which of the following is the input to a controller?(a) Servo signal(b) Desired variable value(c) Error signal(d) Sensed signalI got this question during an online exam.This intriguing question originated from Linear Approximation of the Non-Linear System topic in division Control System and Components of Control Systems
Answer» Right ANSWER is (c) Error signal To explain: Error signal is the input to the CONTROLLER and it causes the output to be the DESIRED output.

Discussion

53.	The pressure inside the furnace is measured by _______(a) Gauge(b) Thermometer(c) Manometer(d) BarometerThis question was addressed to me in exam.The query is from Classification of Control Systems in portion Control System and Components of Control Systems
Answer» The correct option is (a) Gauge The BEST I can EXPLAIN: The pressure inside the furnace is measured by pressure gauge. In case the pressure increases or decreases beyond the desired VALUE, the controller and the actuator will CAUSE a change in the position of the DAMPER.

Discussion

54.	______ control systems have unpredictable & non-repeatable.(a) Static(b) Dynamic(c) Deterministic(d) StochasticThe question was posed to me in quiz.The question is from Classification of Control Systems in portion Control System and Components of Control Systems
Answer» Correct OPTION is (d) Stochastic To elaborate: Stochastic control systems are those who have unpredictable and non-repeatable RESPONSE due to involvement of random parameters. Static systems is the system whose CURRENT output depends only on current input, dynamic system is a TIME dependent systemand deterministic system’s response is predictable and repeatable.

Discussion

55.	The rotor of a stepper motor has no(a) Windings(b) Commutator(c) Brushes(d) All of the mentionedI got this question during an interview for a job.This is a very interesting question from Stepper Motors topic in chapter Control System and Components of Control Systems
Answer» Correct CHOICE is (d) All of the mentioned To explain: The rotor is the rotatory PART of the MOTOR of a STEPPER motor and has no windings, commutator and brushes.

Discussion

56.	In a three-stack 12/8-pole VR motor, the rotor pole pitch is(a) 15º(b) 30º(c) 45º(d) 60ºI have been asked this question during an interview.The doubt is from Stepper Motors in division Control System and Components of Control Systems
Answer» The correct option is (C) 45º To EXPLAIN: Pole pitch is defined as the NUMBER of ARMATURE slots to the pole pitch and here this has been converted into DEGREES.

Discussion

57.	The capacitance, in force-current analogy, is analogous to(a) Momentum(b) Velocity(c) Displacement(d) MassThis question was addressed to me in unit test.This interesting question is from Linear Approximation of the Non-Linear System topic in portion Control System and Components of Control Systems
Answer» RIGHT CHOICE is (d) Mass Explanation: The capacitance in the force current is analogous to the mass and this analogy is also called PARALLEL analogy as MOSTLY all the elements are parallel.

Discussion

58.	Which of the motions in actuators are preferred:(a) Translator(b) Rotary(c) Stationary(d) Non-StationaryThe question was posed to me in class test.My question comes from Controller Components in section Control System and Components of Control Systems
Answer» CORRECT option is (B) Rotary The explanation: An actuator in a control systems perform VARIETY of task in hydraulic, pneumatic and electrical system but majorly they are all CONTROLLING rotary motions.

Discussion

59.	Due to which of the following reasons excessive band width in control systems should be avoided?(a) It leads to slow speed of response(b) It leads to low relative stability(c) Noise is proportional to bandwidth(d) Presence of feedbackI got this question in an interview for job.I'm obligated to ask this question of Linear Approximation of the Non-Linear System in portion Control System and Components of Control Systems
Answer» The correct choice is (C) NOISE is proportional to bandwidth To explain I would say: EXCESSIVE Bandwidth CAUSES INCREASES in the noise with the same proportion as the bandwidth and hence noise is not good for any signal therefore the excessive bandwidth is not desirable.

Discussion

60.	The on-off controller is a _____ system.(a) Digital(b) Linear(c) Non-linear(d) DiscontinuousI had been asked this question in an interview for internship.I need to ask this question from Linear Approximation of the Non-Linear System topic in portion Control System and Components of Control Systems
Answer» Right OPTION is (d) Discontinuous To explain: The on-off CONTROLLER is discontinuous at the point when the SYSTEM changes its STATE from on to off.

Discussion

61.	The torque developed by the motor when stationary with the full applied voltage__________(a) Stalled torque(b) Torque(c) Force(d) CoupleI got this question in an internship interview.This question is from Controller Components in division Control System and Components of Control Systems
Answer» RIGHT option is (a) STALLED torque Easy EXPLANATION: Stalled torque is the important figure of merit of SERVOMOTOR which is important for linearity characteristics.

Discussion

62.	A one-way valve that lets air into the reservoir of a compressor, but doesn’t let it out, is a(a) Check valve(b) Receiver valve(c) Control valve(d) Three way valveI got this question in final exam.This intriguing question originated from Hydraulic Systems topic in section Control System and Components of Control Systems
Answer» The correct CHOICE is (a) Check valve For explanation I would say: Check valve is a one-way valve that LETS AIR into the reservoir of a compressor, but doesn’t LET it out as the name indicates it allows air to ENTER as it has one entrance.

Discussion

63.	Electric actuators for stepped motion are known as stepper motor.(a) True(b) FalseI had been asked this question in an online interview.My query is from Controller Components topic in chapter Control System and Components of Control Systems
Answer» Correct choice is (a) True For explanation I would SAY: STEPPER motors are the motors in which the motion generated is in the form of steps with RESPECT to the time and works on the same principle as electric ACTUATORS but with stepped motion.

Discussion

64.	The lubricator in a pneumatic circuit is the:(a) First element in line(b) Second element in line(c) Last element in line(d) Third element in lineThis question was addressed to me during a job interview.This key question is from Pneumatic Systems topic in chapter Control System and Components of Control Systems
Answer» Right option is (C) LAST element in line To explain I would say: The lubricator is the fluid that is USED to LUBRICATE the parts of the pneumatic circuits to reduce the friction and lubricator in a pneumatic circuit is the last element.

Discussion

65.	Assertion (A): Pneumatic actuators are not as messy as hydraulic ones.Reason (R): Pneumatic suffer from leakages and inherent inaccuracies.(a) Both A and R are true and R is correct explanation of A(b) Both A and R are true but R is not correct explanation of A(c) A is true but R is false(d) A is false but R is trueThe question was asked in an interview.My doubt stems from Controller Components topic in portion Control System and Components of Control Systems
Answer» The CORRECT choice is (B) Both A and R are true but R is not correct explanation of A Explanation: Pneumatic actuators are the devices that convert the motion of AIR into MEASURABLE form of the energy and can also be used in low speed applications but they SUFFER leakages and inherent in accuracies.

Discussion

66.	A single acting cylinder can be pressurized externally from one direction only.(a) True(b) FalseI got this question during an internship interview.This intriguing question originated from Hydraulic Systems topic in division Control System and Components of Control Systems
Answer» The CORRECT option is (a) True Easiest EXPLANATION: Pressure variation is possible only if the force is ACTING from one direction if the force will be acting from multiple directions then the force cancellation is ALSO possible.

Discussion

67.	Speed of a permanent magnet DC motor:(a) It is directly proportional to the armature voltage at a given load torque(b) The speed torque characteristics are more flat than in a wound field motor(c) It depends upon armature voltage and are more flat than in a wound field motor(d) None of the mentionedThe question was asked in a job interview.Question is from Controller Components in division Control System and Components of Control Systems
Answer» The CORRECT answer is (c) It depends upon armature voltage and are more flat than in a wound field motor The explanation: Speed of a PERMANENT magnet DC motor is directly proportional to the armature voltage at a GIVEN load torque and speed torque characteristics are more flat than in a wound field motor as the effect of armature reaction is LESS pronounced in a PM motor.

Discussion

68.	High torque/inertia ratio means:(a) Stalled torque(b) Stalled inertia(c) Stalled toque/inertia ratio(d) Lower motor time constantI had been asked this question during an online interview.The above asked question is from Controller Components topic in portion Control System and Components of Control Systems
Answer» The CORRECT answer is (d) Lower motor time CONSTANT Easiest explanation: High torque/inertia RATIO means the ration of torque to the inertia should be high as for HIGHER torque the inertia must be very LOW and this indicates lower time constant as it leads to dynamic response.

Discussion

69.	PMDC device is commonly employed for:(a) Speed feedback in speed control system(b) Internal velocity feedback loop of a position control system(c) This device is used in both speed feedback and internal velocity feedback control(d) None of the mentionedThis question was posed to me in an interview for internship.This key question is from Controller Components topic in chapter Control System and Components of Control Systems
Answer» Right answer is (c) This device is used in both speed feedback and internal velocity feedback control The EXPLANATION is: The current RATING of this type of device is very SMALL and it is to be CONNECTED to the input end of the OP-AMP.

Discussion

70.	Different type of construction in permanent type DC magnet are :(a) Slotted armature type(b) Surface wound armature type(c) Surface wound rotating armature, stationary wound type.(d) All of the mentionedThis question was addressed to me in an online interview.My question is from Controller Components topic in division Control System and Components of Control Systems
Answer» Correct answer is (d) All of the mentioned For explanation I would say: Permanent magnet are the HARD MAGNETS that have broad B-H curve and can not be used as the core of the transformer due to their high RETENTIVITY and can be CONSTRUCTED by various ways as described above.

Discussion

Explore topic-wise InterviewSolutions in .

The pressure inside the furnace is measured by _______(a) Gauge(b) Thermometer(c) Manometer(d) BarometerThis question was addressed to me in exam.The query is from Classification of Control Systems in portion Control System and Components of Control Systems

______ control systems have unpredictable & non-repeatable.(a) Static(b) Dynamic(c) Deterministic(d) StochasticThe question was posed to me in quiz.The question is from Classification of Control Systems in portion Control System and Components of Control Systems

The rotor of a stepper motor has no(a) Windings(b) Commutator(c) Brushes(d) All of the mentionedI got this question during an interview for a job.This is a very interesting question from Stepper Motors topic in chapter Control System and Components of Control Systems

In a three-stack 12/8-pole VR motor, the rotor pole pitch is(a) 15º(b) 30º(c) 45º(d) 60ºI have been asked this question during an interview.The doubt is from Stepper Motors in division Control System and Components of Control Systems

The capacitance, in force-current analogy, is analogous to(a) Momentum(b) Velocity(c) Displacement(d) MassThis question was addressed to me in unit test.This interesting question is from Linear Approximation of the Non-Linear System topic in portion Control System and Components of Control Systems

Which of the motions in actuators are preferred:(a) Translator(b) Rotary(c) Stationary(d) Non-StationaryThe question was posed to me in class test.My question comes from Controller Components in section Control System and Components of Control Systems

The on-off controller is a _____ system.(a) Digital(b) Linear(c) Non-linear(d) DiscontinuousI had been asked this question in an interview for internship.I need to ask this question from Linear Approximation of the Non-Linear System topic in portion Control System and Components of Control Systems

The torque developed by the motor when stationary with the full applied voltage__________(a) Stalled torque(b) Torque(c) Force(d) CoupleI got this question in an internship interview.This question is from Controller Components in division Control System and Components of Control Systems

Electric actuators for stepped motion are known as stepper motor.(a) True(b) FalseI had been asked this question in an online interview.My query is from Controller Components topic in chapter Control System and Components of Control Systems

A single acting cylinder can be pressurized externally from one direction only.(a) True(b) FalseI got this question during an internship interview.This intriguing question originated from Hydraulic Systems topic in division Control System and Components of Control Systems