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WorksheetsDC MOTORS
Total questions: 23
Worksheet time: 26mins
_____________________ a device used to convert electric energy into mechanical energy.
Motor
Direct Current
Alternating Current
Compass
______________ magnets are created by passing a current through a wire.
compass magnets
electromagnets
DC Motor Magnets
Look at the picture what is letter A?
Armature
Commutator
Permanent Magnet
DC Source
AC Source
Look at the picture what is letter B?
Armature
Commutator
Permanent Magnet
DC Source
AC Source
Look at the picture what is letter C?
Armature
Commutator
Permanent Magnet
DC Source
Brush
Which rule can be used to work out which way a coil of wire rotates in a motor?
Fleming's left-hand rule
Fleming's right-hand rule
Give two ways you can reverse the direction of a basic dc motor?
Reverse the current
Keep the current the same
Reverse the magnetic field
Keep the magnetic field the same
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 prevents the current from becoming too great, because the coil has a low resistance
It reverses the direction of the current in the coil after every 180° rotation of the coil
It switches the current off momentarily after every 90° rotation of the coil
What device changes electrical energy into mechanical energy?
What type of motor is good for use in an electrical fan or centrifugal pump?
What are the 2 types of DC motors?
True or false. A synchronous motor will rotate at a speed that is the same as the applied current?
The part of an electric motor that doesn't spin is called the...
armature
commutator
stator
bearings
In the image shown, the dark grey shapes are called:
Brushes
Armatures
Commutators
Windings
What type of current is flowing in the circuit ?
Alternating current
Direct current
Both
None
Types of DC motor.
Compound field winding Motor
Series field winding Motor
Shunt field winding Motor
All of the above
Shunt Field Winding Motor Characteristic
Assumed a constant speed when loaded or without load
Speed is fixed
The starting torque is not too high
Speed can be controlled
THE WORKING PRINCIPLE OF DC MOTOR IS---------
MUTUAL INDUCTION
FLEMING'S RIGHT HAND
LORENTZ LAW
Magnetic field lines flow
north to south
north to north
south to south
south to north
Which DC motor is preferred for constant speed?
Series motor
Compound motor
Shunt motor
Differential motor
The reason for providing field winding of DC motor with thick wire is
To provide large flux
To carry large load current
To reduce eddy current
To increase the flux
