#1
Which type of protection device is commonly used for motor branch circuits?
Fuse
Circuit breaker
Relay
Resistor
#2
What is the most common voltage rating for motors used in residential applications?
#3
Which type of motor is typically used in HVAC systems?
Induction motor
Synchronous motor
DC motor
Stepper motor
#4
What is the purpose of motor branch-circuit protection?
To prevent electrical shock hazards
To protect the motor against mechanical damage
To prevent excessive current flow and subsequent damage to the motor or circuit
To regulate the voltage supplied to the motor
#5
What is the standard voltage rating for three-phase motors used in industrial applications?
#6
What is the primary reason for using motor branch-circuit protection?
To prevent power interruptions
To protect against power surges
To protect the motor against damage
To regulate motor speed
#7
What is the full-load current (FLC) for a 5 horsepower, 240V, single-phase motor?
10 amps
15 amps
20 amps
25 amps
#8
Which of the following is NOT a method of motor branch-circuit protection?
Overload relays
Motor-rated fuses
Inverse-time circuit breakers
Resistance temperature detectors (RTDs)
#9
What is the NEC requirement for the minimum size of conductors supplying a motor branch circuit?
90% of the motor full-load current (FLC)
100% of the motor FLC
125% of the motor FLC
150% of the motor FLC
#10
In three-phase motor branch-circuit protection, what is the common method used for short-circuit protection?
Magnetic-only circuit breakers
Thermal-only circuit breakers
Magnetic and thermal circuit breakers
Fuse links
#11
What is the purpose of a motor overload relay?
To prevent motor starting
To protect against overcurrent during normal operation
To regulate motor speed
To prevent overheating of the motor
#12
In motor branch-circuit protection, what does the term 'branch circuit' refer to?
The wiring between the motor and the load
The electrical distribution system in a facility
The section of a circuit between the motor controller and the motor
The portion of a circuit supplying power to a single motor
#13
What is the primary function of overload relays in motor protection?
To protect against short circuits
To protect against overcurrent
To protect against overvoltage
To protect against ground faults
#14
What is the recommended method for connecting the protective ground conductor in motor branch-circuit protection?
To the neutral conductor
To the equipment grounding conductor
To the motor casing
To the phase conductors
#15
Which of the following is a typical method of motor overload protection?
Temperature sensors
Time-delay relays
Current transformers
Voltage regulators
#16
What is the typical rating of motor branch-circuit protection devices in terms of voltage and current?
Voltage: 120V, Current: 15A
Voltage: 240V, Current: 30A
Voltage: 480V, Current: 60A
Voltage: 600V, Current: 100A
#17
What is the typical time-delay setting for motor overload relays?
Instantaneous
Short delay (a few milliseconds)
Medium delay (a few seconds)
Long delay (several minutes)