AC and DC motors

What changes the direction of the magnetic field in a DC motor?

• The rotor

• The stator

• The armature coil using a commutator

• The external power source

In an AC motor, what induces a rotating motion in the rotor?

• The armature coil

• The external power source

• The rotating magnetic field produced by the stator

• The commutator

How is the direction of motor movement determined?

• By the size of the motor

• By the interaction between the magnetic fields of the stator and rotor

• By the speed of the rotor

• By the voltage applied

What is the strength of a motor a measure of?

• Its ability to generate torque and perform work

• Its electrical resistance

• Its rotational speed

• Its power consumption

How can the strength of a DC motor be controlled?

• By adjusting the field current or the armature current

• By changing the motor's physical size

• By altering the shaft material

• By using different types of lubricants

In AC motors, what factors control the strength of the motor?

• Applied voltage, frequency, or the number of turns in the winding

• Color and design of the motor

• Type of bearings used

• Ambient temperature

What is the unit of measurement for magnetic flux density?

• Tesla

• Pascal

• Joule

• Coulomb

What does the formula 'F = BIL' represent?

• Force on a conductor

• Energy generated by the motor

• Efficiency of the motor

• Heat dissipation rate

What is the force of the armature in a DC motor with an armature current of 5A, a length of 12m, and a magnetic flux density of 1.3T?

• A) 78 N

• B) 85 N

• C) 65 N

• D) 92 N

Which formula is used to calculate the force of the armature in the given example?

• A) F = BIL

• B) F = IL/B

• C) F = B/LI

• D) F = L/BI