LADWP ELECTRICAL REPAIRER
MAINTENANCE & REPAIR EXAM WITH
QUESTIONS AND VERIFIED ANSWERS,
PLUS DETAILED RATIONALES/EXPERT
VERIFIED FOR GUARANTEED PASS
2026/LATEST UPDATE/INSTANT
DOWNLOAD PDF
1.
An electrical repairer is troubleshooting a large three-phase induction
motor that has developed excessive vibration. The motor is electrically
sound, the measured phase currents are reasonably balanced, and the
vibration increases substantially as speed rises. Which condition should
be investigated FIRST as a likely mechanical cause?
A. Incorrect phase sequence
B. Misalignment between the motor and driven equipment
C. Excessive stator winding resistance
D. Reversed polarity of one control transformer
Answer: B. Misalignment between the motor and driven equipment
Rationale: Misalignment between coupled shafts can produce
substantial radial and axial forces that increase with rotational speed.
It can cause vibration, coupling wear, bearing loading, overheating,
and premature failure even when the electrical characteristics of the
motor appear normal. Phase sequence primarily affects rotation
direction, while winding resistance problems generally produce
electrical imbalance and heating. A control-transformer polarity issue
would more commonly affect control circuitry rather than create
speed-dependent mechanical vibration.
1
,2.
A 240-V resistive heating element draws 20 A during normal operation.
Assuming the element behaves as an approximately pure resistance,
what is its resistance?
A. 4 Ω
B. 8 Ω
C. 12 Ω
D. 20 Ω
Answer: B. 12 Ω
Rationale: Ohm's law gives R = V/I. Therefore, R = 240 V ÷ 20 A = 12
Ω. The distinction is important in maintenance work because knowing
the expected resistance allows a technician to compare an actual meter
measurement with the theoretical value. A substantially higher
reading may indicate an open or deteriorated element, while a
substantially lower reading can indicate a shorted portion of the
element.
3.
Before removing the terminal cover from a motor that has been reported
as malfunctioning, an electrical repairer opens the disconnect and
applies the required lockout/tagout controls. What is the most important
next electrical-safety principle before touching conductors?
A. Assume the circuit is dead because the disconnect is open
B. Verify absence of voltage using an appropriately rated test instrument
C. Short every conductor together immediately
D. Remove the equipment grounding conductor
Answer: B. Verify absence of voltage using an appropriately rated
test instrument
2
,Rationale: Opening a disconnect does not by itself prove that the
equipment is de-energized. Backfeed, incorrect identification, failed
switching devices, stored electrical energy, or other sources can leave
hazardous voltage present. A properly rated meter or tester must be
used according to the applicable procedure to verify the absence of
voltage. Lockout/tagout and verification work together; neither should
be casually substituted for the other.
4.
A three-phase motor has nameplate full-load current of 48 A. During
operation, the measured currents are 47 A, 48 A, and 61 A. Which
conclusion is MOST appropriate?
A. The motor is operating perfectly because the average current is near
52 A
B. The motor should be investigated for electrical or mechanical
imbalance
C. The highest current should be ignored because three-phase motors
naturally have unequal currents
D. The motor must immediately be rewound
Answer: B. The motor should be investigated for electrical or
mechanical imbalance
Rationale: The phase currents are significantly unequal, with one
phase carrying substantially more current than the others. Possible
causes include supply-voltage imbalance, loose or high-resistance
connections, winding problems, unbalanced loading, or mechanical
issues. The motor should not automatically be condemned or rewound
solely from this observation; systematic troubleshooting should
identify the cause. Significant current imbalance can create excessive
heating and reduce motor life.
3
, 5.
An electrical repairer measures continuity across a fuse that has been
removed from the circuit. The meter indicates essentially zero resistance.
What does this measurement normally indicate?
A. The fuse is open
B. The fuse is conducting and is likely intact
C. The fuse has excessive leakage
D. The fuse has reversed polarity
Answer: B. The fuse is conducting and is likely intact
Rationale: A good conventional fuse has very low resistance when
intact, so a continuity test normally produces a low-resistance
indication. An open fuse would show very high resistance or an open-
circuit indication. The test should be performed with the fuse isolated
from energized circuitry because in-circuit measurements can produce
misleading readings and unnecessary hazards.
6.
A motor repeatedly trips its overload protection after approximately 15
minutes of operation. The motor starts normally, but its housing
becomes progressively hotter. Which condition is MOST consistent with
this symptom?
A. Sustained overload or inadequate cooling
B. Excessively high insulation resistance
C. Correctly sized conductors
D. An open auxiliary contact that never closes
Answer: A. Sustained overload or inadequate cooling
4
MAINTENANCE & REPAIR EXAM WITH
QUESTIONS AND VERIFIED ANSWERS,
PLUS DETAILED RATIONALES/EXPERT
VERIFIED FOR GUARANTEED PASS
2026/LATEST UPDATE/INSTANT
DOWNLOAD PDF
1.
An electrical repairer is troubleshooting a large three-phase induction
motor that has developed excessive vibration. The motor is electrically
sound, the measured phase currents are reasonably balanced, and the
vibration increases substantially as speed rises. Which condition should
be investigated FIRST as a likely mechanical cause?
A. Incorrect phase sequence
B. Misalignment between the motor and driven equipment
C. Excessive stator winding resistance
D. Reversed polarity of one control transformer
Answer: B. Misalignment between the motor and driven equipment
Rationale: Misalignment between coupled shafts can produce
substantial radial and axial forces that increase with rotational speed.
It can cause vibration, coupling wear, bearing loading, overheating,
and premature failure even when the electrical characteristics of the
motor appear normal. Phase sequence primarily affects rotation
direction, while winding resistance problems generally produce
electrical imbalance and heating. A control-transformer polarity issue
would more commonly affect control circuitry rather than create
speed-dependent mechanical vibration.
1
,2.
A 240-V resistive heating element draws 20 A during normal operation.
Assuming the element behaves as an approximately pure resistance,
what is its resistance?
A. 4 Ω
B. 8 Ω
C. 12 Ω
D. 20 Ω
Answer: B. 12 Ω
Rationale: Ohm's law gives R = V/I. Therefore, R = 240 V ÷ 20 A = 12
Ω. The distinction is important in maintenance work because knowing
the expected resistance allows a technician to compare an actual meter
measurement with the theoretical value. A substantially higher
reading may indicate an open or deteriorated element, while a
substantially lower reading can indicate a shorted portion of the
element.
3.
Before removing the terminal cover from a motor that has been reported
as malfunctioning, an electrical repairer opens the disconnect and
applies the required lockout/tagout controls. What is the most important
next electrical-safety principle before touching conductors?
A. Assume the circuit is dead because the disconnect is open
B. Verify absence of voltage using an appropriately rated test instrument
C. Short every conductor together immediately
D. Remove the equipment grounding conductor
Answer: B. Verify absence of voltage using an appropriately rated
test instrument
2
,Rationale: Opening a disconnect does not by itself prove that the
equipment is de-energized. Backfeed, incorrect identification, failed
switching devices, stored electrical energy, or other sources can leave
hazardous voltage present. A properly rated meter or tester must be
used according to the applicable procedure to verify the absence of
voltage. Lockout/tagout and verification work together; neither should
be casually substituted for the other.
4.
A three-phase motor has nameplate full-load current of 48 A. During
operation, the measured currents are 47 A, 48 A, and 61 A. Which
conclusion is MOST appropriate?
A. The motor is operating perfectly because the average current is near
52 A
B. The motor should be investigated for electrical or mechanical
imbalance
C. The highest current should be ignored because three-phase motors
naturally have unequal currents
D. The motor must immediately be rewound
Answer: B. The motor should be investigated for electrical or
mechanical imbalance
Rationale: The phase currents are significantly unequal, with one
phase carrying substantially more current than the others. Possible
causes include supply-voltage imbalance, loose or high-resistance
connections, winding problems, unbalanced loading, or mechanical
issues. The motor should not automatically be condemned or rewound
solely from this observation; systematic troubleshooting should
identify the cause. Significant current imbalance can create excessive
heating and reduce motor life.
3
, 5.
An electrical repairer measures continuity across a fuse that has been
removed from the circuit. The meter indicates essentially zero resistance.
What does this measurement normally indicate?
A. The fuse is open
B. The fuse is conducting and is likely intact
C. The fuse has excessive leakage
D. The fuse has reversed polarity
Answer: B. The fuse is conducting and is likely intact
Rationale: A good conventional fuse has very low resistance when
intact, so a continuity test normally produces a low-resistance
indication. An open fuse would show very high resistance or an open-
circuit indication. The test should be performed with the fuse isolated
from energized circuitry because in-circuit measurements can produce
misleading readings and unnecessary hazards.
6.
A motor repeatedly trips its overload protection after approximately 15
minutes of operation. The motor starts normally, but its housing
becomes progressively hotter. Which condition is MOST consistent with
this symptom?
A. Sustained overload or inadequate cooling
B. Excessively high insulation resistance
C. Correctly sized conductors
D. An open auxiliary contact that never closes
Answer: A. Sustained overload or inadequate cooling
4
