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WorksheetsQuiz 3 DJM40103
Total questions: 20
Worksheet time: 13mins
Magnetic field lines flow
south to south
north to south
north to north
outh to north
Fleming's left-hand rule
Fleming's right-hand rule
Faraday's law
Faraday's left-hand rule
Which of these are found
in a simple DC motor?
brushes
split-ring commutator
power supply
slip-ring
What is electric current?
The flow of protons
The flow of electrons
The flow of neutrons
The flow of atoms
Which part (s) of the DC motor connect the power supply to the split-ring and coil?
Slip rings
Magnets
Commutator
Carbon brushes
The operation of Commutator in DC Motor is
convert AC to DC
convert DC to AC
To increase the current from the interaction of magnetic fields
To produce a force from the interaction of magnetic fields
In the image of a DC Motor shown. A is the:
brushes
commutator
stator
rotor
Which of the following motors is type of AC motor?
induction motor
separately excited
self excited
What term applies to the relative difference between the speed of the rotating stator field (Ns) and the rotor speed(Nr)?
synchronous speed
slip
torque
motor speed
S = (ns - nr) / ns, this formula refer to ?
rotor speed
slip of motor
stator speed
frequency of rotor
The formula for calculating synchronous speed is:
Ns= 120f/P
Ns= 120P/f
Ns= f/120P
Ns= P/120f
Given, number of poles is 4 and frequency is 60Hz, Calculate the Synchronous Speed of field rotation Ns=?
1900 rpm
1600 rpm
1800 rpm
2000 rpm
Calculate the slip of Motor , where the Synchronous speed is 1500 rpm and rotational speed is 1400 rpm.
5.68
5.66
6.00
6.67
Which of the following electronic components used in class functions as a switch?
resistor
capacitor
transistor
conductor
A simple DC electric motor is fitted with a coil that rotates in a magnetic field. A commutator connects the power supply to the coil.
What is the purpose of the commutator?
It converts AC into DC in the coil.
It reverses the direction of the current in the coil after every 180° rotation of the coil
It prevents the current from becoming too great, because the coil has a low resistance
It switches the current off momentarily after every 90° rotation of the coil
The rotor is the name of the part that is
the rotating coil inside the stator's field
the spring loaded parts that contact the commutator
the stationary magnets around the rotating coil
the split ring that carries electricity to the coil
Main advantage of an ac motor as compared to a DC motor is
less maintenance
can work in any environment
expensive
controllability
A 50 Hz, 3-phase induction motor has a full load speed of 1440 r.p.m. The number of poles in the motor is
2 pole
3 pole
4 pole
6 pole
The field winding of a three phase synchronous machine is excited by
Single-phase ac supply
Dc supply
THREE-phase ac supply
