NCCER 26211-20 QUESTIONS AND

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NCCER 26211-20 | QUESTIONS AND

VERIFIED SOLUTIONS LATEST

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Question : A motor is connected L1 to T1, L2 to T2, and

L3 to T3. To reverse the motor, the leads need to be connected _____.

CORRECT ANSWER : L1 to T3, L2 to T2, and L3 to T1

Question : A motor overload relay consists of a current-

sensing unit and a mechanism activated by the sensing unit that _____.

CORRECT ANSWER : opens the motor circuit

Question : A shading coil is used to _____.

CORRECT ANSWER : prevent contact chatter

Question : A single-pushbutton contact can be used to

control the sequence of operation of several loads by using a _____.

CORRECT ANSWER : multi-pole relay

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Question : An opto-isolated solid state relay is activated

by _____.

CORRECT ANSWER : light

Question : Contacts that are apart when the relay is de-

energized are said to be _____.

CORRECT ANSWER : normally open

Question : If contactor action is dependent on current

flow, the contactor is described as _____.

CORRECT ANSWER : electrically held

Question : Increasing the armature spring force in a relay

will result in _____.

CORRECT ANSWE R: higher drop-out values

Question : Low-voltage remote control switching relays

_____.

CORRECT ANSWER : use a split low-voltage coil

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Question : Mechanically held relays and contactors are

often used in auditoriums because _____.

CORRECT ANSWER : they are quieter than electrically

held devices

Question : Power to operate low-voltage switching

systems is supplied by _____.

CORRECT ANSWER : a transformer

Question : The lubrication of a large industrial motor at

prescribed intervals can be accomplished using a _____.

CORRECT ANSWER : timing relay

Question : The overload relays in machines associated

with continuous processing typically activate a(n) _____.

CORRECT ANSWER : alarm circuit

Question : The panel for a low-voltage lighting control

system enclosure should be mounted _____.

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CORRECT ANSWER : at eye level between two studs

Question : The symbol shown in the figure provided is

used to denote a low-voltage _____.

CORRECT ANSWER : transformer

Question : The two classifications of overload relays are

thermal and _____.

CORRECT ANSWER : magnetic

Question : Which of the following is a nonrenewable

device?

CORRECT ANSWER : Time-delay fuse

Question : Which of the following is a probable cause of

relay-controlled equipment failing to start when the contactor is closed?

CORRECT ANSWER : One contact not closing