Question 1
What is the main purpose of a disconnecting means installed within sight of a motor?
Question 2
In a low-voltage control circuit for lighting, why might a relay panel be used instead of switching line-voltage conductors directly at each switch?
Question 3
You need to check the continuity of a control circuit that is de-energized. Which instrument setting is most appropriate?
Question 4
You are tasked with selecting conductors and overcurrent protection for a single three-phase motor load. Which design approach is most appropriate?
Question 5
A small air compressor on a 15 A, 120 V circuit causes the breaker to trip occasionally at startup, even though the running current is only 9 A. What is the most appropriate solution?
Question 6
A 15 HP, 600V, 3-phase induction motor has a nameplate Full Load Amps (FLA) of 17A. What is the minimum ampacity rating for the branch circuit conductors?
Question 7
What is the maximum setting of a time-delay fuse used for motor branch circuit protection?
Question 8
A 15 HP, 600V, 3-phase motor has a nameplate Full Load Amps (FLA) of 17A. What is the minimum ampacity for the branch circuit conductors?
Question 9
What is the maximum time-delay fuse setting for a motor branch circuit?
Question 10
During troubleshooting, you find that a motor’s overload relay frequently trips after the motor runs for several minutes, even though the overcurrent device does not trip. What is the most likely issue?
Question 11
On a schematic for a motor control circuit, what does a dashed line connecting a contact to a coil usually indicate?
Question 12
In a motor starter, what is the primary function of the overload relay?
Question 13
You are troubleshooting a control circuit where a contactor coil does not energize. You measure control voltage on one side of the coil but not on the other. Which failure is most likely?
Question 14
A 2 hp, 240 V single-phase motor has a nameplate full-load current of 12 A. If the branch-circuit short-circuit and ground-fault protective device is sized at 250% of the motor FLC, what is the nearest standard overcurrent device rating?
Question 15
What is the primary function of a power distribution block (PDB) in a control panel?
Question 16
A $240\text{ V}$ motor is drawing $28 \text{ A}$ at full load. The motor is protected by a standard fuse rated at $175\%$ of the FLC. What is the maximum standard fuse rating permitted?
Question 17
A 10 hp, 3-phase, 480 V motor has a full-load current (FLC) of 14 A per its nameplate. For a continuous-duty application, which branch-circuit conductor ampacity is MOST appropriate when sizing conductors at 125 percent of the motor FLC (ignoring correction factors)?
Question 18
A 10 hp, 3-phase, 480V motor has a nameplate Full Load Amps (FLA) of 14A. What current value should be used to size the branch circuit conductors?