MMET 301 Final Exam questions with
verified answers
Force - correct answer ✔✔A push or pull exerted on an object
Friction - correct answer ✔✔A force that opposes motion
Torque - correct answer ✔✔Force * Distance
RPM - correct answer ✔✔revolutions per minute
Power - correct answer ✔✔the rate at which work is done
Efficiency - correct answer ✔✔= Power out / Power In
Electric motors - correct answer ✔✔current creates electromagnetic field
Types of Electric motors - correct answer ✔✔AC & DC motors
AC ( Alternating Current) Motors - correct answer ✔✔- Found in homes
- Current travels in both directions
- Low voltage
Single phase AC motor - correct answer ✔✔only one voltage waveform is applied to motor
Three phase AC motors - correct answer ✔✔three wires supply voltage to motor
,Rotor - correct answer ✔✔The rotating member of an electric motor
Stator - correct answer ✔✔stationary outer shell of electric motor
Synchronous speed - correct answer ✔✔Rotational speed of stator's magnetic field
Slip - correct answer ✔✔Difference between actual rotor and Synchronous speed
Speed-torque curve - correct answer ✔✔shows torque values critical for motor selection
Locked rotor torque - correct answer ✔✔torque at zero speed, used for accelerating the load
Pull-up torque - correct answer ✔✔minimum torque during acceleration from rest the speed where
breakdown occurs
Breakdown torque - correct answer ✔✔torque produced by motor just before it stops turning due to
heavy load and application
shaded pole motor - correct answer ✔✔copper loop surrounds each stator pole
Split -phase motor - correct answer ✔✔two sets of stator windings in the motor
capacitor - start motor - correct answer ✔✔has start and run windings
capacitor - start capacitor - run motor - correct answer ✔✔uses two capacitor to provide magnetic field
shift
permanent split - capacitor motor - correct answer ✔✔identical main and auxiliary windings to provide
starting torque
, Frequency - correct answer ✔✔the number of times in once second an alternating current voltage
switches
USA Hertz - correct answer ✔✔60 Hz
Causes of motor overheating - correct answer ✔✔- changes of energy
- over work
- improper motor size
- incorrect voltage
- repeated starts
- poor ventilation
constant - torque load - correct answer ✔✔demand for horsepower that is in direct proportion to the
speed of the load
variable - torque load - correct answer ✔✔
Motor insulation - correct answer ✔✔windings are coated prevent shorting
Service Factor - correct answer ✔✔the amount of overload a motor can continuously deliver without
overheating
Speed Torque - correct answer ✔✔maximum available torque a motor can deliver at any given speed
Open drip proof - correct answer ✔✔Suitable for clean, dry, indoor environments, has vent holes
Drip Proof Blower Ventilated - correct answer ✔✔motors that are often frequently starts and overloads
Totally enclosed non-ventilated - correct answer ✔✔no external fan, dissipates all heat through frame
verified answers
Force - correct answer ✔✔A push or pull exerted on an object
Friction - correct answer ✔✔A force that opposes motion
Torque - correct answer ✔✔Force * Distance
RPM - correct answer ✔✔revolutions per minute
Power - correct answer ✔✔the rate at which work is done
Efficiency - correct answer ✔✔= Power out / Power In
Electric motors - correct answer ✔✔current creates electromagnetic field
Types of Electric motors - correct answer ✔✔AC & DC motors
AC ( Alternating Current) Motors - correct answer ✔✔- Found in homes
- Current travels in both directions
- Low voltage
Single phase AC motor - correct answer ✔✔only one voltage waveform is applied to motor
Three phase AC motors - correct answer ✔✔three wires supply voltage to motor
,Rotor - correct answer ✔✔The rotating member of an electric motor
Stator - correct answer ✔✔stationary outer shell of electric motor
Synchronous speed - correct answer ✔✔Rotational speed of stator's magnetic field
Slip - correct answer ✔✔Difference between actual rotor and Synchronous speed
Speed-torque curve - correct answer ✔✔shows torque values critical for motor selection
Locked rotor torque - correct answer ✔✔torque at zero speed, used for accelerating the load
Pull-up torque - correct answer ✔✔minimum torque during acceleration from rest the speed where
breakdown occurs
Breakdown torque - correct answer ✔✔torque produced by motor just before it stops turning due to
heavy load and application
shaded pole motor - correct answer ✔✔copper loop surrounds each stator pole
Split -phase motor - correct answer ✔✔two sets of stator windings in the motor
capacitor - start motor - correct answer ✔✔has start and run windings
capacitor - start capacitor - run motor - correct answer ✔✔uses two capacitor to provide magnetic field
shift
permanent split - capacitor motor - correct answer ✔✔identical main and auxiliary windings to provide
starting torque
, Frequency - correct answer ✔✔the number of times in once second an alternating current voltage
switches
USA Hertz - correct answer ✔✔60 Hz
Causes of motor overheating - correct answer ✔✔- changes of energy
- over work
- improper motor size
- incorrect voltage
- repeated starts
- poor ventilation
constant - torque load - correct answer ✔✔demand for horsepower that is in direct proportion to the
speed of the load
variable - torque load - correct answer ✔✔
Motor insulation - correct answer ✔✔windings are coated prevent shorting
Service Factor - correct answer ✔✔the amount of overload a motor can continuously deliver without
overheating
Speed Torque - correct answer ✔✔maximum available torque a motor can deliver at any given speed
Open drip proof - correct answer ✔✔Suitable for clean, dry, indoor environments, has vent holes
Drip Proof Blower Ventilated - correct answer ✔✔motors that are often frequently starts and overloads
Totally enclosed non-ventilated - correct answer ✔✔no external fan, dissipates all heat through frame
