1) How is proximity switch differentiated from limit switch?
a. proximity switch is activated when moving parts have physical contact with it
b. proximity switch is activated when non-moving parts have physical contact
c. proximity switch is activated when moving parts are close to it
d. none of the above
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Answer
Explanation
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ANSWER: proximity switch is activated when moving parts are close to it
Explanation:
No explanation is available for this question!
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2) Which of the following statements is true?
a. electromagnetic relays have high reliability at more cost
b. electromagnetic relays use low current and voltage, to have open or close contact in high voltage and current circuit
c. air pressure passed to pressure electric converter opens a contact which energizes a circuit for the flow of electric contact
d. all of the above
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Answer
Explanation
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ANSWER: electromagnetic relays use low current and voltage, to have open or close contact in high voltage and current circuit
Explanation:
No explanation is available for this question!
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3) In which circuits, relay of low voltage and low current is used to make open or close contact?
a. high voltage and high current circuit
b. low voltage and low current circuit
c. high voltage and low current circuit
d. low voltage and low current circuit
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4) In electropneumatic circuits,
a. spool is shifted by signal air
b. spool is shifted by control air
c. spool is shifted by electromotive force
d. all of the above
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5) Why are electromechanical relays more popular than solid state relays?
a. they are reliable
b. less costly
c. both a. and b.
d. none of the above
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6) In which control valve energy consumption reduces as load decreases?
a. conventional direction control valve
b. proportional direction control valve
c. both a. and b.
d. none of the above
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7) Which of the following is a characteristic of servo valve?
a. open loop system
b. closed loop system
c. less contamination
d. all of the above
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8) What is PLC?
a. Process logic control
b. Programmable language converter
c. Programmable logic control
d. Programmable logic converter
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9) What causes burning of AC solenoid coil?
a. holding current
b. in rush current
c. current clamps
d. all of the above
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10) When PLC connections are used instead of electrical connections, the order of operations to be performed can be interchanged by
a. changing hardwired connections
b. changing sequence of program
c. both a. and b.
d. none of the above
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11) Which of the following reasons make water unsuitable to use as a fluid in hydraulic systems?
1. Poor lubrication
2. High viscosity
3. More leakage
4. Quickly evaporates
a. 1 and 3
b. 2 and 4
c. 1, 3 and 4
d. all of the above
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12) The heat generated in hydraulic systems can be absorbed by
a. lubrication
b. cooling
c. sealing
d. all of the above
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13) In sliding spool valves hydraulic fluid acts as sealant to reduce leakage
a. True
b. False
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14) For which of the following purpose hydraulic film acts as a seal between the machined cavity and spool?
a. to reduce leakage
b. for cooling purposes
c. for lubrication purposes
d. all of the above
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15) Which of the following statements are true?
1. Low viscosity fluids have higher leakage
2. High viscosity fluids have high pressure drop
3. Low viscosity fluids consume more power
4. Low viscosity leads to wear of components
a. 1 and 2
b. 1, 2 and 3
c. 1, 2 and 4
d. 2, 3 and 4
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16) Pressure applied on a fluid in a container is equally distributed in all directions and acts with
a. equal force on equal areas parallelly
b. equal force on different areas and at right angles
c. equal force on equal areas and at right angles
d. none of the above
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Answer
Explanation
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ANSWER: equal force on equal areas and at right angles
Explanation:
No explanation is available for this question!
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17) Which law explains the behavior of hydraulic fluids under pressure?
a. Charles's law
b. Newtons law
c. Pascal's law
d. none of the above
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18) Flow of oil in a pipe takes place due to
a. balanced forces
b. unbalanced forces
c. both balanced and unbalanced forces
d. none of the above
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19) Pressure drop in pipes, occurs due to
a. frictional resistance
b. load
c. flow pattern
d. none of the above
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20) How is laminar flow characterized in a straight pipe?
a. flow of high shear stress
b. flow of high velocity
c. flow of low-velocity
d. none of the above
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21) Positive displacement pump used in hydraulic systems have
a. high viscosity of fluids
b. low efficiency
c. required volume of fluid cannot be discharged
d. all of the above
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22) Electric motor has a speed of 1200 rpm and output rate of pump is 6 cc/rev. Calculate flow rate of pump in l/min
a. 6 l/min
b. 7.2 l/min
c. 5 l/min
d. none of the above
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23) Calculate the power absorbed by the pump if, it has a flow rate of 20 cc/rev and develops a maximum pressure of 70 bar, when electric motor runs at a speed of 1200 rpm.
a. 1.9 kW
b. 2.8 kW
c. 2.3 kW
d. none of the above
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24) Volumetric efficiency is the ratio of
a. theoretical flow rate to actual flow rate
b. actual flow rate to theoretical flow rate
c. actual fluid power to pump input power
d. none of the above
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25) Which of the following is a hydrodynamic pump?
a. vane pump
b. centrifugal pump
c. gear pump
d. piston pump
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26) What causes reduction in speed of the piston rod when the hydraulic cylinder is cushioned?
a. oil flow through small space
b. back pressure created in the system
c. both a. and b.
d. none of the above
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27) Which of the following is a hydraulic cylinder based on application?
a. welded
b. bolted
c. ram
d. all of the above
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28) What happens when supply of oil to a single acting cylinder is stopped?
a. no pressure is exerted on the system
b. more pressure is exerted on the piston
c. less pressure is exerted on the piston
d. none of the above
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29) When does expansion of spring and retraction of cylinder take place in spring type single acting cylinder?
a. oil pressure exerted is less than spring compression pressure
b. oil pressure exerted is more than spring compression pressure
c. oil pressure exerted and spring compression pressure are same
d. none of the above
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Answer
Explanation
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ANSWER: oil pressure exerted is less than spring compression pressure
Explanation:
No explanation is available for this question!
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30) Double acting cylinder can be used as a single acting cylinder
a. True
b. False
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31) In a telescopic cylinder, as the number of stages increase
a. diameter of piston rod also increases
b. diameter of piston rod decreases
c. diameter of the piston rod remains the same
d. none of the above
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32) Why are bleed off circuits used?
a. bleed off circuit is used to restrict the flow of fluid into the hydraulic cylinder
b. bleed off circuit is used to restrict the flow of fluid out of the hydraulic cylinder
c. bleed off circuits are used to reduce the speed of actuator
d. all of the above
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Answer
Explanation
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ANSWER: bleed off circuits are used to reduce the speed of actuator
Explanation:
No explanation is available for this question!
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33) Which of the following is applicable for bleed off circuits?
a. bleed off circuits develop heat in the system
b. bleed off circuits are used for resistive loads
c. bleed off circuits are used for runaway loads
d. all of the above
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Answer
Explanation
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ANSWER: bleed off circuits are used for resistive loads
Explanation:
No explanation is available for this question!
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34) What is the function of sequence valve used in hydraulic circuits?
a. sequence valves are used to perform number of operations one after the other after the set pressure is reached
b. sequence valves are used to perform number of operations continuously before the set pressure is reached
c. sequence valves after reaching set pressure oil is flown to the tank
d. all of the above
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Answer
Explanation
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ANSWER: sequence valves are used to perform number of operations one after the other after the set pressure is reached
Explanation:
No explanation is available for this question!
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35) When is a pressure reducing valve used?
a. it is used when higher pressure than system pressure is required
b. it is used when lower pressure than system pressure is required
c. when absolutely zero pressure is required
d. all of the above
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Answer
Explanation
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ANSWER: it is used when lower pressure than system pressure is required
Explanation:
No explanation is available for this question!
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36) How is strong magnetic field in a solenoid achieved?
a. strong magnetic field in a solenoid is achieved, if coil acts as conductor
b. coil is surrounded by a iron frame
c. iron core is placed at the centre of the coil
d. all of the above
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37) What is the DC range of of solenoids in pneumatic systems?
a. 12 V and 24 V
b. 110 V and 220 V
c. both a. and b.
d. none of the above
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38) Which of the following is used an output device on a ladder diagram?
a. proximity sensor
b. detent switch
c. relay
d. all of the above
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39) The output device on a ladder diagram is represented by
a. square
b. circle
c. rectangle
d. semicircle
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40) Write instructions for the NAND connections given below, which has A and B two switches connected in parallel
a.
steps 0 1 2
components A B X
instruction LDI ANI OUT
b.
steps 0 1 2
components A B X
instruction LD AND OUT
c.
steps 0 1 2
components A B X
instruction LD OR OUT
d.
steps 0 1 2
components A B X
instruction LDI ORI OUT
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Answer
Explanation
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ANSWER:
steps 0 1 2
components A B X
instruction LDI ORI OUT
Explanation:
No explanation is available for this question!
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41) In mnemonics instructions, what does I in LDI indicate?
a. switch is normally open
b. switch is normally closed
c. it indicates operating of second switch
d. none of the above
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42) In industrial applications hydraulic fluids have viscosity grade ranging from
a. 20 to 50
b. 70 to 95
c. 46 to 68
d. 15 to 44
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43) High viscosity fluids have
a. low pressure drop
b. less power consumption
c. slow operation
d. all of the above
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44) What is viscosity index?
a. effect of pressure on changes in viscosity
b. effect of temperature on changes in viscosity
c. effect of resistance between two surfaces
d. none of the above
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Answer
Explanation
Related Ques
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ANSWER: effect of temperature on changes in viscosity
Explanation:
No explanation is available for this question!
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45) Highest temperature at which a fluid in hydraulic system flows is called its pour point.
a. True
b. False
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46) Which property decides the behavior of fluid when mixed with water?
a. pour point
b. demulsibility
c. viscosity
d. oxidation
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47) For any operation in a hydraulic system the fluid should have pour point
a. 20 0F below the lowest temperature
b. 20 0F above the lowest temperature
c. 20 0C below the lowest temperature
d. 20 0C above the lowest temperature
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48) What is the disadvantage of petroleum based fluids?
a. low flash point
b. low density
c. light weight
d. all of the above
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49) How is the water content in High Water Fluids (HFA) compared to oil content?
a. more oil than water
b. oil and water are in same proportion
c. more water than oil
d. contains only water
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50) A fluid used in hydraulic systems should have
a. low oxidation resistance
b. high oxidation resistance
c. high oxidation enhancing ability
d. none of the above
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