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Section 1: Relay Fundamentals and Operation
Question 1
When an elevator constructor describes a normally open (NO) contact or a
making contact, he or she is describing the same contact configuration.
A) True
B) False
C) Only in AC circuits
D) Only when used with relays
Correct Answer: A) True
Rationale: A normally open contact and a making contact both describe a contact
that is open in its normal (de-energized) state and closes when actuated. These
terms are interchangeable in elevator schematics and control logic .
Question 2
As current flows through a relay's coil, what is generated by the coil that pulls or
picks the relay's armature?
A) Static charge
B) Heat
C) Magnetic field
D) Back EMF
Correct Answer: C) Magnetic field
Rationale: Current flowing through a coil creates a magnetic field, which attracts
the relay armature and changes the state of the contacts. This electromagnetic
action is the basis of relay operation .
,Question 3
The most common relay used in modern elevator control systems is the plug-type
relay.
A) True
B) False
C) Only in DC systems
D) Only in traction elevators
Correct Answer: A) True
Rationale: Plug-type relays are favored due to ease of replacement, reliability,
and minimal downtime, making them standard in modern elevator controllers .
Question 4
The majority of today's set/reset relays operate by using two independent coils
mounted on a common relay base.
A) True
B) False
C) Only when timed
D) Only in AC systems
Correct Answer: A) True
Rationale: Set/reset (latching) relays typically use two separate coils—one to set
the relay and one to reset it—on a common base. This design maintains contact
position without continuous power .
Question 5
How are latching relays reset?
A) Manually
B) Mechanically
C) Electrically
D) Hydraulically
Correct Answer: C) Electrically
, Rationale: Latching relays are reset electrically by energizing the reset coil, which
returns the contacts to their normal position .
Question 6
What is the primary purpose of a relay in an elevator control system?
A) Increase voltage
B) Store electrical energy
C) Control one circuit with another
D) Limit current
Correct Answer: C) Control one circuit with another
Rationale: The fundamental purpose of a relay is to act as a switch. A low-power
control circuit can energize the relay's coil, which then allows the relay's contacts
to safely open or close a separate, higher-power circuit .
Question 7
A contact that is closed when a relay is de-energized is called:
A) Normally open
B) Making contact
C) Normally closed
D) Transitional contact
Correct Answer: C) Normally closed
Rationale: Normally closed contacts conduct current until the relay is energized,
at which point they open. They are often used for safety circuits and holding
circuits .
Question 8
What happens to the magnetic field of a relay coil when power is removed?
A) It reverses
B) It increases