Motors Book - Chapter 4
- 1.A ___ motor transfer energy from electric power to the load through the use of a rotating magnetic field.
- A.
Design
- B.
Single-phase
- C.
3-phase
- D.
DC
- 2.A ___ is the fixed, unmoving part of motor, consisting of a core and windings, that converts electrical energy to the energy of a magnetic field.
- A.
Motor shaft
- B.
Drum switch
- C.
Cartridge fuse
- D.
Stator
- 3.The most common types of rotors are used in squirrel-cage induction motors, ___ motors, and synchronous motors.
- A.
Wound-rotor
- B.
Open
- C.
Salient
- D.
Flux
- 4.As the rotor begins to move, the frequency of the induced current in the rotor decreases, until the rotor approaches synchronous speed, where the rotor frequency approaches ___ Hz.
- A.
0
- B.
50
- C.
60
- D.
120
- 5.A single-___ motor is a motor that operates at only one voltage level.
- A.
Design
- B.
Voltage
- C.
Stator
- D.
Torque
- 6.In a ___ motor, one end of each of the three phase windings is internally connected to the other phase windings.
- A.
Single-voltage, delta connected
- B.
Dual-voltage, wye connected, three-phase
- C.
Wye connected, single-phase
- D.
Wye connected, 3-phase
- 7.In a ___ motor, each phase is wired end-to-end to form a completely closed circuit.
- A.
Single-voltage, wye connected, three-phase
- B.
Dual-voltage, wye connected, three-phase
- C.
Delta-connected, 3-phase
- D.
Delta-connected, single-phase
- 8.A typical dual-voltage, 3-phase motor rating is ___V.
- A.
230/460
- B.
240/480
- C.
208-230/460
- D.
All of the above
- 9.The common types of torque related to motors are locked-rotor torque and ___ torque.
- A.
Full-load
- B.
Pull-up
- C.
Breakdown
- D.
All of the above
- 10.___ power is the product of the total current and voltage in a circuit.
- A.
Reactive
- B.
Apparent
- C.
True
- D.
Motor
- 11.___ loss is the total energy loss in the stator and rotor cores due to circulating currents and to the magnetic field escaping from the core.
- A.
Resistance
- B.
Core
- C.
Bearing
- D.
Hysteresis
- 12.A ___ is a motor component used to reduce friction and maintain clearance between the stationary parts and the moving shaft.
- A.
Bearing
- B.
Motor shaft
- C.
Fuse
- D.
Eutectic alloy
- 13.The motor ___ indicates whether a motor is rated to operate at 50 Hz, 60 Hz, or both.
- A.
Label
- B.
Identification tag
- C.
Nameplate
- D.
Load
- 14.Motors for ___ loads are designed to give the same maximum torque at all speeds.
- A.
Variable-horsepower
- B.
Variable-torque
- C.
Constant-horsepower
- D.
Constant-torque
- 15.___ loss is the loss of flux in the air gap because the air gap has increased reluctance compared to the cores.
- A.
Bearing
- B.
Flux-linkage
- C.
Windage
- D.
Sound
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