Multiple Choice
Identify the
choice that best completes the statement or answers the question.
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1.
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Which one of the following is not a component of a time-delay relay?
a. | Coil | c. | Alarm | b. | Timing mechanism | d. | Contacts |
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2.
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An on-delay timer relay’s contacts will not change states until
a. | the coil has deenergized. | c. | the coil has been
energized. | b. | a predetermined time has elapsed. | d. | the circuit is turned
off. |
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3.
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The ___________ timer operates in a manner that is opposite to the on-delay
timer.
a. | off-delay | c. | pneumatic | b. | instantaneous | d. | solid-state |
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4.
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In order to avoid seriously overheating the motor on a centrifugal air
compressor at startup, it is recommended that
a. | the motor be overhauled. | d. | All of these | b. | the motor be
unloaded when started. | e. | None
of these | c. | the oil be changed every week. |
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5.
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One machine that uses a time-delay relay to perform a cylinder dwell is
a(n)
a. | automatic carwash. | c. | plastic injection molding machine. | b. | centrifugal air
compressor. | d. | washing
machine. |
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6.
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When time-delay relays are used in time-driven sequencing, they basically take
the place of
a. | limit switches. | c. | stop pushbuttons. | b. | start pushbuttons. | d. | manual
overrides. |
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7.
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One reason why machines use multiple cylinders operating together is to
a. | reduce cost. | d. | All of the these | b. | reduce labor. | e. | None of these | c. | provide extra
force. |
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8.
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Which of the following is a method for synchronizing cylinders?
a. | Flow control valves | d. | All of these | b. | Optical sensors | e. | None of these | c. | Time-delay
relay |
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9.
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How many limit switches are needed if the cylinders to be synchronized are
attached to the same machine member.
a. | One | c. | Three | b. | Two | d. | Cannot be
determined |
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10.
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An example of using one limit switch to control multiple cylinders is the
a. | crimping press. | d. | All of these | b. | hydraulic press. | e. | None of these | c. | printing
press. |
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11.
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Controlling two cylinders that are not attached to the same machine part
requires
a. | one limit switch. | c. | four limit switches. | b. | two limit switches. | d. | Cannot
determine |
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12.
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An application of the two limit switch control method is a
a. | hydraulic press. | c. | crimping machine. | b. | printing press. | d. | shearing press. |
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13.
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Which of the following is a mode of operation for a machine?
a. | Manual | d. | All of these | b. | Standby | e. | None of these | c. | Semi-automatic |
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14.
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How are machines usually changed from automatic to manual mode?
a. | A special program | c. | Limit switch | b. | Selector switch | d. | Pushbutton
switch |
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15.
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Which mode is usually used for machine setup and maitenance?
a. | Manual | d. | All of the these | b. | Automatic | e. | None of these | c. | Standby |
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16.
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The manual control of cylinders through pushbuttons is called
a. | stepping | c. | jogging | b. | running | d. | creeping |
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17.
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Which of the following is not a basic guideline to follow when working with
manual control circuits?
a. | Energize solenoids through relays if possible. | d. | All of these | b. | Jogging should be
done at highest machine speed. | e. | None of these | c. | When the machine is in the manual mode, the
automatic mode should be locked out. |
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Matching
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Segment 1
a. | normally open | d. | off-delay | b. | normally closed | e. | time-delay or timer | c. | timing | f. | after |
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18.
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A(n) ____________ relay is a type of control relay that switches its contacts
to a new state after a predetermined time has elapsed.
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19.
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The three basic components of a timer-delay relay are the coil, the contacts,
and the ____________ mechanism.
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20.
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The symbol shown is a(n) ____________ on-delay relay contact.
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21.
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The two basic operating modes for a time-delay relay are on-delay and
__________.
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22.
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An on-delay timer relay causes its contacts to change states ___________ the
preset time has elapsed.
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23.
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The symbol shown is a(n) ____________ off-delay relay contact.
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Segment 2
a. | cylinder | d. | timer | b. | dwell | e. | Time-driven | c. | compressor |
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24.
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An example of an unloaded start of a motor is on a centrifugal air
_________.
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25.
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A plastic injection mold is an example of an operation that uses a(n) _________
dwell.
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26.
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__________ sequencing uses timer relays in place of limit switches to sequence
the operation of a machine.
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27.
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For each distinct operation that takes place in a time-driven operation, a(n)
_________ must be assigned.
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28.
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Before the mold on a plastic injection molding machine is pulled apart, a(n)
___________ period must occur to allow the plastic to cool and harden.
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Segment 3
a. | hydraulic press | e. | two | b. | parallel | f. | force | c. | crimping | g. | AND | d. | limit |
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29.
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One reason why machines sometimes use multiple cylinders working together is to
provide the extra ___________ needed to move the load.
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30.
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A(n) ___________ is an application where cylinders are connected to the same
machine part to synchronize ther operation.
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31.
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Using one ________ switch to control multiple cylinders is usually only used
when the cylinders are attached to the same machine number.
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32.
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If you have two cylinders to control, and they are not attached to the same
machine member, you will need to use __________ limit switches.
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33.
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An example of a machine that uses two limit switches to control two cylinders
is a(n) __________ machine.
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34.
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Connecting two N.O. limit switches in series to control two cylinders is called
___________ logic.
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35.
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Controlling two cylinders using NAND logic requires connecting two N.C. limit
switches in _________.
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Segment 4
a. | jogging | f. | selector | b. | jog | g. | control relays | c. | malfunction | h. | slowest | d. | four | i. | automatic | e. | Manual | j. | five |
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36.
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The normal operating mode for most machines is the _________ mode.
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37.
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________ mode is most often used in machine setup and maintenance.
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38.
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A(n) _________ switch is most often used to determine the desired operating
mode.
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39.
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The manual control of a cylinder with a pushbutton is know as
_________.
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40.
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The two basic applications for manual controls on automatic machines is
operator control of the machine and ___________.
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41.
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Pushbuttons used for jogging are called ___________ pushbuttons.
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42.
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There are __________ basic guidelines to follow when working with manual
control circuits.
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43.
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Guideline number 2 says that jogging should be done at the ________ machine
speed in order to provide maximum safety.
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44.
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Guideline number 1 says that it is better to energize solenoids through
________.
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45.
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Guideline number __________ says that when a machine is in the manual mode, the
automatic mode must be completely locked out.
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