410

b. 6

A motor that is to be started in wye and run in delta must have at least ___ leads. Select one: a. 9 b. 6 c. 3

d. all of these

SCRs are used in solid-state starters. SCRs ___. Select one: a. have no contacts b. are small in size c. are rugged d. all of these

c. is less than

When autotransformer starting is used to start a motor, the line current through the motor branch circuit ___ the current through the conductors on the load side of the starter. Select one: a. equals b. is more than c. is less than

b. False

When solid-state starting is used, full voltage is never applied to the motor. Select one: a. True b. False

d. 58

When wye-delta starting is used, the voltage across each motor winding in the wye configuration is approximately ___ % of the line-to-line voltage. Select one: a. 225 b. 175 c. 125 d. 58

b. six

Wye-delta motors are specially wound with ___ leads extending from the motor to enable the windings to be connected in either a wye or delta configuration. Select one: a. two b. six c. eight d. four

c. Full-load

___ current is the amount of current drawn by a motor when operating at nameplate speed. Select one: a. Increment b. Locked-rotor c. Full-load d. Reaction

d. Ohm's law

___ is used to calculate motor starting current. Select one: a. Inrush calulator software b. Thess' theory of inrush current c. Motor start theory d. Ohm's law

d. full

Solid-state overloads are set by selecting a current limit based on ___ load current ratings listed on the motor nameplate and the trip class setting (class 10, 15, 20, or 30). Select one: a. locked b. standard c. starting d. full

d. high resistance

A starting rheostat reduces the voltage applied to a DC motor during starting by placing a ___ in series with the motor. Select one: a. current regulator b. low capacitance c. frequency reducer d. high resistance

d. delta

A wye-delta motor normally has a higher starting torque when started in ___. Select one: a. forward b. reverse c. wye d. delta

c. wye

A wye-delta motor normally has a lower starting torque when started in ___. Select one: a. forward b. reverse c. wye d. delta

b. two

A wye-delta starter has ___ contactor(s). Select one: a. only one b. two c. six

c. six

A wye-delta starter requires the motor to be internally connected in the peckerhead so that ___ conductors are extended to the starter enclosure. Select one: a. three b. two c. six

c. an FVNR starter

Starting a motor using ___ is considered to be a "hard" start. Select one: a. an ASD b. a solid-state starter c. an FVNR starter d. any of these

b. current

Starting torque and ___ of a motor are reduced when a reduced-voltage starting method is used to start the motor. Select one: a. speed b. current c. cost of operation d. impedance

c. both a and b

Full-voltage starting (hard starts) can cause ___. Select one: a. thermal stresses in the motor b. stress mechanical coupling between the motor and the driven load c. both a and b d. neither a nor b

b. never

If a motor is started at reduced voltage, the motor is ___ disconnected from the voltage source when closed circuit transition is used. Select one: a. momentarily b. never

a. momentarily

If a motor is started at reduced voltage, the motor is ___ disconnected from the voltage source when open circuit transition is used. Select one: a. momentarily b. never

a. energy-efficient

In addition to using reduced-voltage starting methods for large-horsepower motors, replacing older motors with ___ motors can lead to reduced electrical power costs. Select one: a. energy-efficient b. single-phase c. three-phase d. any of these

a. is

An ASD ___ a method of soft starting. Select one: a. is b. is not

c. both a and b

If a reduced-voltage starting method that reduces starting torque too much is selected, ___. Select one: a. the overloads will trip b. the motor won't start c. both a and b d. neither a nor b

c. greater starting torque

What advantage does autotransformer starting have over primary-resistor starting? Select one: a. uses full-voltage starting b. smoother acceleration of the load c. greater starting torque

c. 6

A wye-delta starter requires the use of a ___ lead motor for proper operation. Select one: a. 3 b. 9 c. 6

a. soft

A(n) ___ starter provides a gradual voltage increase to a motor while starting. Select one: a. soft b. across-the-line

a. counter EMF

As a motor accelerates up to rated speed, the winding currents are reduced from those at start due to the ___ developed in the motor. Select one: a. counter EMF b. excessive heat c. phase shift d. all of these

f. II only

Because of the heat dissipation required during the start, run, and stop cycles, a contactor is often connected in parallel with a soft starter. Motor circuit current flows through the contactor contacts during the ___ cycle. I. start II. run III. stop Select one: a. II & III only b. II only c. I & III only d. I only e. I & II only f. II only

b. reduced-voltage

Because of utility system limitations, large-horsepower motors generally use ___ starting. Select one: a. across-the-line b. reduced-voltage

d. all of these

Compared to an across-the-line starter, a solid-state starter ___. Select one: a. reduces inrush current b. minimizes starting torque c. ramps up motor voltage d. all of these

b. increases

Counter EMF ___ as the motor speed increases. Select one: a. decreases b. increases

d. motor current

In autotransformer starting, transformer ___ and line current are not equal as they are in primary resistor starting. Select one: a. stator speed b. flux lines c. frequency drives d. motor current

c. two

In part-winding starting, the motor stator windings must be divided into ___ or more equal parts for a motor to be started using part-winding starting. Select one: a. three b. four c. two d. one

c. extra-smooth

Multiple-step starting is possible by using additional contacts and resistors when ___ starting and acceleration are needed. Select one: a. fast b. smooth c. extra-smooth d. higher torque

a. higher

Open circuit transition produces a ___ current surge than closed circuit transition at the transition point from reduced-voltage starting. Select one: a. higher b. lower

b. current and torque

Part-winding starting is classified as a reduced-voltage starting method but actually has reduced ___ when starting. Select one: a. voltage and current b. current and torque c. voltage and torque

c. resistors

Primary resistor starting can provide extra smooth starting and acceleration when additional contacts and ___ are used. Select one: a. starters b. transitions c. resistors d. pushbuttons

d. speed

The flow rates for fans and pumps can be controlled using an ASD. The ASD controls the flow rates by increasing or decreasing the motor ___. Select one: a. linkage b. torque c. kvA d. speed

b. reduce starting current

The primary reason to use other than a full-voltage starting method is to ___. Select one: a. control a motor's speed b. reduce starting current c. start difficult loads

c. both I and II

The required equipment used for a wye-delta starting method includes ___. I. a two-speed starter II. an on-delay timing relay Select one: a. I only b. II only c. both I and II d. neither I nor II

a. before

When a reduced-voltage starting method is used to start a motor, the motor must be switched to full line voltage ___ the motor reaches full speed. Select one: a. before b. when c. after

d. III only

Which of the following methods of reduced-voltage starting have adjustable starting currents? I. part-winding II. wye-delta III. solid-state Select one: a. I & III only b. II & III only c. I & II only d. III only e. II only f. I only

e. I & III only

Which of the starting methods listed below is considered a reduced-voltage starting method? I. wye-delta II. across-the-line III. autotransformer Select one: a. II only b. I only c. III only d. I & II only e. I & III only

c. full-voltage

Which starting method is the least expensive and most efficient means of starting small-horsepower motors? Select one: a. part-winding b. wye-delta c. full-voltage d. autotransformer e. primary-resistor