HVACR 101 BASIC ELECTRICAL-CONTACTORS/
RELAYSTEST#2 QUESTIONS WITH DETAILED
VERIFIED AND 100% ACCURATE ANSWERS
HVACR 101 BASIC ELECTRICAL – CONTACTORS/RELAYS TEST #2
Practice Examination – 100 Questions with Verified Answers
SECTION 1: RELAY FUNDAMENTALS
Question 1
A relay is basically an electrically operated:
A. Resistor
B. Switch
C. Capacitor
D. Transformer
Answer: B
Explanation: A relay is an electrically operated switch. Its contacts change state
when the proper voltage is applied to the coil.
Question 2
Relays are designed for amperages of:
A. More than 50 amperes
B. Less than 20 amperes
C. 20 to 40 amperes
D. Any amperage
,Answer: B
Explanation: Relays are designed for amperages of less than 20 amperes.
Contactors handle more than 20 amperes.
Question 3
The two main components of a relay are the coil and the:
A. Capacitor
B. Contacts
C. Transformer
D. Diode
Answer: B
Explanation: A relay has a coil (electromagnet) and a series of electrical contacts.
When current passes through the coil, a magnetic field moves a metal armature,
opening or closing the contacts.
Question 4
Relays provide _____ between the control circuit and the circuit being controlled.
A. Continuity
B. Isolation
C. Resistance
D. Capacitance
Answer: B
Explanation: Relays provide isolation between the control circuit and the circuit
being controlled. This allows safe 24V controls to control 240V components.
Question 5
A relay with a single switch or set of contacts is referred to as a:
,A. Double pole relay
B. Single pole relay
C. Three-way relay
D. Multi-pole relay
Answer: B
Explanation: A relay with a single switch or set of contacts is referred to as a single
pole relay.
Question 6
Which of the following is NOT an electromagnetic device?
A. Contactor
B. Relay
C. Sequencer relay
D. Ohmmeter
Answer: D
Explanation: An ohmmeter is a measuring instrument, not an electromagnetic
device. Contactors, relays, and sequencer relays are all electromagnetic devices.
Question 7
The coil on a contactor or relay can be determined open, shorted, or good by
using a(n):
A. Voltmeter
B. Ammeter
C. Ohmmeter
D. Manometer
Answer: C
Explanation: An ohmmeter is used to check the coil of a contactor or relay to
determine if it is open, shorted, or good.
, Question 8
A contactor coil should have a measurable amount of resistance, approximately:
A. 5 ohms
B. 50 ohms
C. 500 ohms
D. 5,000 ohms
Answer: B
Explanation: The contactor coil should have a measurable amount of resistance,
approximately 50 ohms. A reading of zero ohms indicates a shorted coil.
Question 9
If an ohmmeter reads zero ohms when checking a contactor coil, this indicates:
A. The coil is good
B. The coil is open
C. The coil is shorted
D. The meter is broken
Answer: C
Explanation: A reading of zero ohms indicates a shorted coil. The condensing unit
will not energize until the coil is replaced.
Question 10
What are the coil voltages commonly used in the HVACR field for contactors?
A. 12, 24, 120
B. 24, 115, 208/230
C. 5, 10, 15
D. 240, 480, 600
RELAYSTEST#2 QUESTIONS WITH DETAILED
VERIFIED AND 100% ACCURATE ANSWERS
HVACR 101 BASIC ELECTRICAL – CONTACTORS/RELAYS TEST #2
Practice Examination – 100 Questions with Verified Answers
SECTION 1: RELAY FUNDAMENTALS
Question 1
A relay is basically an electrically operated:
A. Resistor
B. Switch
C. Capacitor
D. Transformer
Answer: B
Explanation: A relay is an electrically operated switch. Its contacts change state
when the proper voltage is applied to the coil.
Question 2
Relays are designed for amperages of:
A. More than 50 amperes
B. Less than 20 amperes
C. 20 to 40 amperes
D. Any amperage
,Answer: B
Explanation: Relays are designed for amperages of less than 20 amperes.
Contactors handle more than 20 amperes.
Question 3
The two main components of a relay are the coil and the:
A. Capacitor
B. Contacts
C. Transformer
D. Diode
Answer: B
Explanation: A relay has a coil (electromagnet) and a series of electrical contacts.
When current passes through the coil, a magnetic field moves a metal armature,
opening or closing the contacts.
Question 4
Relays provide _____ between the control circuit and the circuit being controlled.
A. Continuity
B. Isolation
C. Resistance
D. Capacitance
Answer: B
Explanation: Relays provide isolation between the control circuit and the circuit
being controlled. This allows safe 24V controls to control 240V components.
Question 5
A relay with a single switch or set of contacts is referred to as a:
,A. Double pole relay
B. Single pole relay
C. Three-way relay
D. Multi-pole relay
Answer: B
Explanation: A relay with a single switch or set of contacts is referred to as a single
pole relay.
Question 6
Which of the following is NOT an electromagnetic device?
A. Contactor
B. Relay
C. Sequencer relay
D. Ohmmeter
Answer: D
Explanation: An ohmmeter is a measuring instrument, not an electromagnetic
device. Contactors, relays, and sequencer relays are all electromagnetic devices.
Question 7
The coil on a contactor or relay can be determined open, shorted, or good by
using a(n):
A. Voltmeter
B. Ammeter
C. Ohmmeter
D. Manometer
Answer: C
Explanation: An ohmmeter is used to check the coil of a contactor or relay to
determine if it is open, shorted, or good.
, Question 8
A contactor coil should have a measurable amount of resistance, approximately:
A. 5 ohms
B. 50 ohms
C. 500 ohms
D. 5,000 ohms
Answer: B
Explanation: The contactor coil should have a measurable amount of resistance,
approximately 50 ohms. A reading of zero ohms indicates a shorted coil.
Question 9
If an ohmmeter reads zero ohms when checking a contactor coil, this indicates:
A. The coil is good
B. The coil is open
C. The coil is shorted
D. The meter is broken
Answer: C
Explanation: A reading of zero ohms indicates a shorted coil. The condensing unit
will not energize until the coil is replaced.
Question 10
What are the coil voltages commonly used in the HVACR field for contactors?
A. 12, 24, 120
B. 24, 115, 208/230
C. 5, 10, 15
D. 240, 480, 600
