Instrumentation Transducers

Electro Mechanical Systems

Question 1
Marks : +2 | -2
Pass Ratio : 100%
Which of the following is the correct conversion in an electro mechanical system?
Electrical to electrical
Electrical to mechanical
Mechanical to electrical
Both electrical to mechanical and mechanical to electrical
Explanation:
Electro mechanical systems convert electrical quantity to mechanical quantity and vice versa.
Question 2
Marks : +2 | -2
Pass Ratio : 100%
Current to force and current to torque conversion is possible only for a constant current source.
True
False
Explanation:
For consistent and stable conversion of current to mechanical quantities constant current supply is required.
Question 3
Marks : +2 | -2
Pass Ratio : 100%
Tacho generators are ______________
Zero-order system
First-order system
Second order system
None of the mentioned
Explanation:
Zero-order systems have a constant transfer function. Tacho-generators are working based on induced emf due to the movement of conductors in a magnetic field, developed speed will be proportional to speed and hence transfer function will have a constant value.
Question 4
Marks : +2 | -2
Pass Ratio : 100%
Which of the following represents transfer function of tacho-generators?
Kg
1/Kg
SKg
S2Kg
Explanation:
Tacho generators are zero order systems, in which transfer function will be a constant value. Kg represents generator constant or back emf constant.
Question 5
Marks : +2 | -2
Pass Ratio : 100%
For a constant field dc motor, what is the relation between the mechanical time constant and armature resistance?
Direct proportionality
Inverse proportionality
Double
Equal
Explanation:
Mechanical time constant is given by relation JR / K2, in which R is the armature resistance.
Question 6
Marks : +2 | -2
Pass Ratio : 100%
What is the relation between eddy current damping coefficient and resistance in PMMC device?
Direct proportionality
Inverse proportionality
Constant
None of the mentioned
Explanation:
In PMMC devices eddy current damping ratio and resistance shows inverse proportionality. As resistance increases, the damping ratio decreases.
Question 7
Marks : +2 | -2
Pass Ratio : 100%
Torque developed by a DC motor will be proportional to armature current.
True
False
Explanation:
In a DC motor armature current is the essential part of producing rotatory motion, and armature current will be directly proportional to torque output.
Question 8
Marks : +2 | -2
Pass Ratio : 100%
Transfer function of force motor is _____________
Kg
SKg
Kf
SKf
Explanation:
Transfer function of force motor is a constant term since, it is a zero-order system. Kf stands for force constant.
Question 9
Marks : +2 | -2
Pass Ratio : 100%
Which of the following represents for torque speed characteristic for dc motor?
Positive slope
Negative slope
Slope zero
None of the mentioned
Explanation:
Torque speed characteristic of a dc motor has a negative slope with slope Kt/R, is essential for a motor to come to rest when the applied voltage is made zero.
Question 10
Marks : +2 | -2
Pass Ratio : 100%
Most electrical indicating instruments are electromechanical systems since ________________
They are used to measure electric component
They are more precise
They require no external power to operate
They convert electrical quantity to mechanical quantity
Explanation:
Electromechanical systems are which converts electrical quantity to mechanical quantity. Most electronic indicating instruments works on this principle, and they are electromechanical instruments.