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JATC Year 3: Motor Control - Mid Term > MC II: Lesson 6 - Special Purpose Starters > Flashcards

MC II: Lesson 6 - Special Purpose Starters Flashcards

1
Q

Smaller 3-phase motors are normally controlled using ______ across the line starters.

a. full voltage
b. reduced voltage

A

a. full voltage

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2
Q

The high inrush currents for large horsepower AC motors can cause interference on the power distribution system.

True or False

A

True

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3
Q

Reduced voltage starting techniques for DC motors have replaced DC motor drives in many DC motor applications.

True or False

A

False

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4
Q

Most power distribution systems are designed for huge current fluctuations on their power grid.

True or False

A

False

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5
Q

Reduced voltage starting ______ inrush currents and ______ the impact on the distribution systems.

a. increases / intensifies
b. lowers / lessens

A

b. lowers / lessens

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6
Q

______ is one of the most efficient and effective reduced voltage starting techniques.

a. Autotransformer starting
b. Part-winding starting
c. Primary resistor starting
d. Soft-start starting
e. Solid-state reduced voltage starting
f. Wye-delta starting

A

a. Autotransformer starting

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7
Q

Autotransformer starters are best suited for what types of motors?

a. Squirrel cage
b. Synchronous
c. Wound-rotor

A

a. Squirrel cage

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8
Q

Autotransformer starters function by maintaining a relatively ______ primary current, but allows a ______ secondary current to start the motor.

a. high / higher
b. low / higher
c. low / lower

A

b. low / higher

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9
Q

______ are constructed with two or three wye-connected single-winding autotransformers connected to timer-controlled contactors.

a. Autotransformer starting
b. Part-winding starting
c. Primary resistor starting
d. Soft-start starting
e. Solid-state reduced voltage starting
f. Wye-delta starting

A

a. Autotransformer starting

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10
Q

The windings of the autotransformers are typically tapped at ______ , ______ , or ______ of the line voltage.

a. 40% / 55% / 70%
b. 50% / 65% / 80%
c. 60% / 75% / 90%

A

b. 50% / 65% / 80%

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11
Q

______ offer more reduction of line current than any other reduced voltage starting method.

a. Autotransformer starting
b. Part-winding starting
c. Primary resistor starting
d. Soft-start starting
e. Solid-state reduced voltage starting
f. Wye-delta starting

A

a. Autotransformer starting

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12
Q

______ are one of the best options when maximum starting torque and minimum starting current are required for a particular application.

a. Autotransformer starting
b. Part-winding starting
c. Primary resistor starting
d. Soft-start starting
e. Solid-state reduced voltage starting
f. Wye-delta starting

A

a. Autotransformer starting

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13
Q

In applications that require frequent starting or long acceleration periods, a(n) ______ would work very well.

a. Autotransformer starting
b. Part-winding starting
c. Primary resistor starting
d. Soft-start starting
e. Solid-state reduced voltage starting
f. Wye-delta starting

A

a. Autotransformer starting

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14
Q

Which type of autotransformer starter only has autotransformers in two legs of the three-phase supply?

a. Closed transition
b. Open transition

A

a. Closed transition

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15
Q

Cost and ______ conditions are the two biggest disadvantages of an autotransformer starter with an autotransformer in each leg of the 3-phase supply.

a. closed transition
b. open transition

A

b. open transition

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16
Q

______ is a reduced voltage starting technique that connects a resistor in series with each phase supplying the motor.

a. Autotransformer starting
b. Part-winding starting
c. Primary resistor starting
d. Soft-start starting
e. Solid-state reduced voltage starting
f. Wye-delta starting

A

c. Primary resistor starting

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17
Q

The addition of resistance in series with each phase produces a voltage drop across the resistor, resulting in a reduced voltage and current to the motor while starting. Once the motor accelerates to the proper speed, a contactor controlled by a timer closes contacts that are wired in parallel with the resistors, effectively shunting the resistors in each phase and connecting the motor directly to full line voltage.

This explains what starter operation?

a. Autotransformer starting
b. Part-winding starting
c. Primary resistor starting
d. Soft-start starting
e. Solid-state reduced voltage starting
f. Wye-delta starting

A

c. Primary resistor starting

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18
Q

When operations require a slow and constant start, ______ should be used.

a. Autotransformer starting
b. Part-winding starting
c. Primary resistor starting
d. Soft-start starting
e. Solid-state reduced voltage starting
f. Wye-delta starting

A

c. Primary resistor starting

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19
Q

If faster acceleration is required, additional resistors should be added in parallel to the existing resistors and controlled by additional timers and contactors to a primary resistor starter.

True or False

A

False

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20
Q

Typically, ______ drop the voltage and current values to approximately 80% of the normal line readings.

a. Autotransformer starting
b. Part-winding starting
c. Primary resistor starting
d. Soft-start starting
e. Solid-state reduced voltage starting
f. Wye-delta starting

A

c. Primary resistor starting

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21
Q

Heat is the biggest disadvantage of ______.

a. Autotransformer starting
b. Part-winding starting
c. Primary resistor starting
d. Soft-start starting
e. Solid-state reduced voltage starting
f. Wye-delta starting

A

c. Primary resistor starting

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22
Q

When applications require modest reductions in line current and torque while providing smooth acceleration, ______ would be best suited.

a. Autotransformer starting
b. Part-winding starting
c. Primary resistor starting
d. Soft-start starting
e. Solid-state reduced voltage starting
f. Wye-delta starting

A

c. Primary resistor starting

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23
Q

What motor starting technique applies power to part of the motor windings at startup and then connects the remaining coils for normal speed?

a. Autotransformer starting
b. Part-winding starting
c. Primary resistor starting
d. Soft-start starting
e. Solid-state reduced voltage starting
f. Wye-delta starting

A

b. Part-winding starting

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24
Q

Full voltage is applied to the motor at all times through acceleration and up to normal speed in what type of starting method?

a. Autotransformer starting
b. Part-winding starting
c. Primary resistor starting
d. Soft-start starting
e. Solid-state reduced voltage starting
f. Wye-delta starting

A

b. Part-winding starting

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25
Q

Current reductions are achieved by temporarily modifying the wiring configurations to the motor in which types of starting?
I. Autotransformer starting
II. Part-winding starting
III. Primary resistor starting
IV. Soft-start starting
V. Solid-state reduced voltage starting
VI. Wye-delta starting

a. I. and II.
b. I. and IV.
c. II. and VI.
d. III. and IV.

A

c. II. and VI.

26
Q

A part-winding starter is only used with a ______ motor capable of part-winding starting.

a. dual voltage
b. single voltage
c. wound-rotor

A

a. dual voltage

27
Q

The windings of dual voltage motors have ______ set(s) of coils in each winding.

a. 1
b. 2
c. 3

A

b. 2

28
Q

The coils of a dual voltage motor are connected in ______ for higher voltage and in ______ for lower voltage.

a. parallel /series
b. series /parallel

A

b. series /parallel

29
Q

Since part-winding starters are connected to only one set of coils at startup and both sets of coils in parallel when the motor is up to speed, the motor must operate at the ______ voltage reading.

a. higher
b. lower

A

b. lower

30
Q

A part-winding starter requires ______ motor starter(s) and one timing relay.

a. 1
b. 2
c. 3

A

b. 2

31
Q

The two motor starters of a part winding starter can be sized for one-half of the FLC of the motor since neither starter will conduct more than one-half of the motor current except at startup.

True or False

A

True

32
Q

Motor feed conductors can be sized based upon current measurements made in the field.

True or False

A

False

33
Q

______ requires no special equipment and is inexpensive to purchase, install, and maintain.

a. Autotransformer starting
b. Part-winding starting
c. Primary resistor starting
d. Soft-start starting
e. Solid-state reduced voltage starting
f. Wye-delta starting

A

b. Part-winding starting

34
Q

Part-winding starting is not suitable for long startup times or high inertia loads.

True or False

A

True

35
Q

A special six-lead or twelve-lead motor that can be connected in either a wye or delta configuration must be used in which type of starting method?

a. Autotransformer starting
b. Part-winding starting
c. Primary resistor starting
d. Soft-start starting
e. Solid-state reduced voltage starting
f. Wye-delta starting

A

f. Wye-delta starting

36
Q

The wye winding is used in the ______ configuration, and the delta winding is used in the ______ configuration.

a. run / start
b. start / run

A

b. start / run

37
Q

______ are one of the least expensive options for large horsepower motors.

a. Autotransformer starting
b. Part-winding starting
c. Primary resistor starting
d. Soft-start starting
e. Solid-state reduced voltage starting
f. Wye-delta starting

A

f. Wye-delta starting

38
Q

The basic wye-delta starter configuration is designed for ______ transition starting, although ______ transition starters are available at an extra cost.

a. closed / open
b. open / closed

A

b. open / closed

39
Q

______ are best suited for applications where low starting torque and minimal line current are required.

a. Autotransformer starting
b. Part-winding starting
c. Primary resistor starting
d. Soft-start starting
e. Solid-state reduced voltage starting
f. Wye-delta starting

A

f. Wye-delta starting

40
Q

In ______, a silicon-controlled rectifier (SCR) controls the voltage and current to the motor during acceleration.

a. Autotransformer starting
b. Part-winding starting
c. Primary resistor starting
d. Soft-start starting
e. Solid-state reduced voltage starting
f. Wye-delta starting

A

e. Solid-state reduced voltage starting

41
Q

A(n) ______ is composed of a cathode, anode, and gate.

a. diode
b. SCR
c. triac

A

b. SCR

42
Q

When a signal is applied to the ______, it acts as a “trigger” that turns the SCR on and off.

a. anode
b. cathode
c. gate

A

c. gate

43
Q

By triggering the SCR on and off at specific intervals during each cycle of the sine wave, this starting method controls the voltage and current delivered to the motor windings while the motor is accelerating.

a. Autotransformer starting
b. Part-winding starting
c. Primary resistor starting
d. Soft-start starting
e. Solid-state reduced voltage starting
f. Wye-delta starting

A

e. Solid-state reduced voltage starting

44
Q

The ______ the gate has a signal, the ______ the SCR remains on, and the greater the voltage and current is supplied to the motor.

a. longer / longer
b. shorter / longer
c. shorter / shorter

A

a. longer / longer

45
Q

______ provide the smoothest acceleration and greatest control of current and torque for squirrel cage motors than any other starting technique.

a. Autotransformer starting
b. Part-winding starting
c. Primary resistor starting
d. Soft-start starting
e. Solid-state reduced voltage starting
f. Wye-delta starting

A

e. Solid-state reduced voltage starting

46
Q

______ controllers are electronic devices that offer greater control during the starting and stopping of a motor.

a. Autotransformer starting
b. Part-winding starting
c. Primary resistor starting
d. Soft-start starting
e. Solid-state reduced voltage starting
f. Wye-delta starting

A

d. Soft-start starting

47
Q

______ controllers offer adjustable ramp-up time by gradually increasing the voltage and current supplied to the motor and ramp-down control that reduces motor voltage and current for deceleration.

a. Autotransformer starting
b. Part-winding starting
c. Primary resistor starting
d. Soft-start starting
e. Solid-state reduced voltage starting
f. Wye-delta starting

A

d. Soft-start starting

48
Q

______ controllers are commonly used in applications requiring smooth starting and stopping of motors and driven machinery.

a. Autotransformer starting
b. Part-winding starting
c. Primary resistor starting
d. Soft-start starting
e. Solid-state reduced voltage starting
f. Wye-delta starting

A

d. Soft-start starting

49
Q

______ starters are used in industrial processes that require the motor to run both forward and backward.

a. Combination
b. Reduced voltage
c. Reversing

A

c. Reversing

50
Q

Swapping any two power phase leads will reverse the direction of a three-phase motor.

True or False

A

True

51
Q

The industry standard for reversing a three-phase motor is to switch which two power leads?

a. L1 (phase A) and L2 (phase B)
b. L1 (phase A) and L3 (phase C)
c. L2 (phase B) and L3 (phase C)

A

b. L1 (phase A) and L3 (phase C)

52
Q

Reversing starters consist of ______ contactor(s) and ______ overload relay assembly (assemblies).

a. 1 / 1
b. 2 / 1
c. 2 / 2

A

b. 2 / 1

53
Q

______ interlocks prevent both the forward and the reverse contactors from closing at the same time using a cam to prevent the simultaneous closing of the two armatures.

a. Electrical
b. Mechanical

A

b. Mechanical

54
Q

______ interlocks operate through auxiliary contacts on the contactors that disable the coil of a second contactor when the first contactor is closed or disable the first contactor when the second contactor is closed.

a. Electrical
b. Mechanical

A

a. Electrical

55
Q

Reversing motor starters are normally factory wired for electrical interlocking.

True or False

A

True

56
Q

A forward/reverse starter requires two overload relay assemblies.

True or False

A

False

57
Q

The dotted lines in the diagram identify ______.

a. auxiliary interlocks
b. electrical interlocks
c. hidden lines
d. mechanical interlocks

A

d. mechanical interlocks

58
Q

Although the combination of mechanical and electrical interlocks provides a high level of protection in reversing circuits, ______ is sometimes used when an additional form of interlocking is required.

a. operator warning
b. pushbutton interlocking
c. software interlocking

A

b. pushbutton interlocking

59
Q

When troubleshooting reduced voltage starters, the voltage during the running stage should be ______ the line voltage.

a. equal to
b. greater than
c. less than

A

a. equal to

60
Q

In troubleshooting a control circuit, the first step is to verify that ______ are (is) present.

a. control power
b. interlocking contacts
c. overload contacts

A

a. control power

61
Q

Troubleshooting control circuits involves using a ______ to analyze the control logic.

a. ladder diagram
b. one-line diagram
c. starter manufacture drawing
d. wiring diagram

A

a. ladder diagram

JATC Year 3: Motor Control - Mid Term (8 decks)

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