LADWP ELECTRICAL REPAIRER EXAM —
CLASS 3853 WITH QUESTIONS AND
VERIFIED ANSWERS, PLUS DETAILED
RATIONALES/EXPERT VERIFIED FOR
GUARANTEED PASS 2026/LATEST
UPDATE/INSTANT DOWNLOAD PDF
1. A three-phase induction motor is brought into the repair shop
because it repeatedly trips its overload protection after
approximately 10 minutes of operation. The motor runs normally
for the first several minutes, and the overload eventually trips.
Which diagnostic approach is MOST appropriate?
A. Immediately replace the overload relay with one of a higher rating
B. Measure winding resistance only while the motor is energized
C. Check load current on all three phases, compare the readings, and
inspect for mechanical overloading, voltage imbalance, and winding
problems
D. Short-circuit the overload relay temporarily to determine whether the
motor can continue operating
Answer: C. Check load current on all three phases, compare the
readings, and inspect for mechanical overloading, voltage
imbalance, and winding problems
Rationale: A motor that operates normally when cold but trips after
heating can have several causes, including excessive mechanical load,
poor ventilation, voltage imbalance, unequal phase current, bearing
problems, or winding deterioration. Measuring and comparing all
three phase currents provides important diagnostic information.
Increasing or bypassing overload protection can create a serious
1
,equipment and fire hazard rather than correcting the underlying
problem.
2. Before dismantling an electrical motor for repair, which
procedure is MOST important?
A. Remove the bearings first so the shaft can rotate freely
B. Apply compressed air to the motor while it is energized
C. Establish electrical isolation, lockout/tagout, verify absence of
voltage, and document connections and component locations
D. Remove all terminal leads without recording their original positions
Answer: C. Establish electrical isolation, lockout/tagout, verify
absence of voltage, and document connections and component
locations
Rationale: Safe electrical repair begins with control of hazardous
energy. Lockout/tagout prevents unexpected energization, while
verification establishes that the equipment is actually de-energized.
Documenting connections before disassembly helps ensure accurate
reassembly and prevents wiring errors.
3. During inspection of a motor winding, the insulation appears
darkened and brittle, and there is a distinct burnt odor. What does
this condition MOST strongly indicate?
A. Normal aging with no need for further testing
B. Possible overheating and thermal deterioration of insulation
C. Excessive lubrication of the bearings only
D. A properly cured winding
Answer: B. Possible overheating and thermal deterioration of
insulation
2
,Rationale: Darkened, brittle insulation and a burnt odor are classic
indicators of thermal stress or overheating. The repairer should
investigate possible causes such as overload, locked rotor conditions,
inadequate cooling, voltage abnormalities, phase imbalance, or
repeated starting. Simply rewinding without identifying the cause may
result in another premature failure.
4. What is the primary purpose of an insulation-resistance test on a
motor winding?
A. To determine the motor's horsepower
B. To determine the exact bearing clearance
C. To evaluate the condition of insulation between the winding and
ground or other conductive parts
D. To measure the motor's mechanical speed
Answer: C. To evaluate the condition of insulation between the
winding and ground or other conductive parts
Rationale: An insulation-resistance tester applies a controlled DC test
voltage and measures resistance through the insulation system. A low
or deteriorating insulation resistance can indicate moisture,
contamination, aging, carbonization, or insulation damage.
5. A motor winding has acceptable insulation resistance to ground
but shows significantly different resistance values between its three
phase windings. What should the repairer suspect?
A. A possible winding imbalance, incorrect connection, or damaged
winding
B. Perfect winding symmetry
C. Excessive bearing grease only
D. Correct operation with no further investigation necessary
3
, Answer: A. A possible winding imbalance, incorrect connection, or
damaged winding
Rationale: Comparable phase-to-phase winding resistance is normally
expected in a properly constructed three-phase motor, allowing for
design and measurement tolerances. A substantial difference can
indicate an open or damaged conductor, poor connection, incorrect
winding configuration, or other winding defect.
6. Why is it important to record the original lead identification
before disconnecting a motor?
A. To determine the motor's paint color
B. To ensure the winding and terminal connections can be restored
correctly
C. To increase the motor's rated voltage
D. To eliminate the need for electrical testing after repair
Answer: B. To ensure the winding and terminal connections can be
restored correctly
Rationale: Motor leads can have multiple connection arrangements
depending on voltage, starting method, and winding configuration.
Accurate identification prevents phase-sequence errors, incorrect
voltage connections, reversed rotation, circulating currents, or
winding damage.
7. A motor shaft exhibits excessive radial movement during
inspection. Which component should receive particular attention?
A. Terminal block
B. Bearing assembly
C. Nameplate
D. Grounding conductor
4
CLASS 3853 WITH QUESTIONS AND
VERIFIED ANSWERS, PLUS DETAILED
RATIONALES/EXPERT VERIFIED FOR
GUARANTEED PASS 2026/LATEST
UPDATE/INSTANT DOWNLOAD PDF
1. A three-phase induction motor is brought into the repair shop
because it repeatedly trips its overload protection after
approximately 10 minutes of operation. The motor runs normally
for the first several minutes, and the overload eventually trips.
Which diagnostic approach is MOST appropriate?
A. Immediately replace the overload relay with one of a higher rating
B. Measure winding resistance only while the motor is energized
C. Check load current on all three phases, compare the readings, and
inspect for mechanical overloading, voltage imbalance, and winding
problems
D. Short-circuit the overload relay temporarily to determine whether the
motor can continue operating
Answer: C. Check load current on all three phases, compare the
readings, and inspect for mechanical overloading, voltage
imbalance, and winding problems
Rationale: A motor that operates normally when cold but trips after
heating can have several causes, including excessive mechanical load,
poor ventilation, voltage imbalance, unequal phase current, bearing
problems, or winding deterioration. Measuring and comparing all
three phase currents provides important diagnostic information.
Increasing or bypassing overload protection can create a serious
1
,equipment and fire hazard rather than correcting the underlying
problem.
2. Before dismantling an electrical motor for repair, which
procedure is MOST important?
A. Remove the bearings first so the shaft can rotate freely
B. Apply compressed air to the motor while it is energized
C. Establish electrical isolation, lockout/tagout, verify absence of
voltage, and document connections and component locations
D. Remove all terminal leads without recording their original positions
Answer: C. Establish electrical isolation, lockout/tagout, verify
absence of voltage, and document connections and component
locations
Rationale: Safe electrical repair begins with control of hazardous
energy. Lockout/tagout prevents unexpected energization, while
verification establishes that the equipment is actually de-energized.
Documenting connections before disassembly helps ensure accurate
reassembly and prevents wiring errors.
3. During inspection of a motor winding, the insulation appears
darkened and brittle, and there is a distinct burnt odor. What does
this condition MOST strongly indicate?
A. Normal aging with no need for further testing
B. Possible overheating and thermal deterioration of insulation
C. Excessive lubrication of the bearings only
D. A properly cured winding
Answer: B. Possible overheating and thermal deterioration of
insulation
2
,Rationale: Darkened, brittle insulation and a burnt odor are classic
indicators of thermal stress or overheating. The repairer should
investigate possible causes such as overload, locked rotor conditions,
inadequate cooling, voltage abnormalities, phase imbalance, or
repeated starting. Simply rewinding without identifying the cause may
result in another premature failure.
4. What is the primary purpose of an insulation-resistance test on a
motor winding?
A. To determine the motor's horsepower
B. To determine the exact bearing clearance
C. To evaluate the condition of insulation between the winding and
ground or other conductive parts
D. To measure the motor's mechanical speed
Answer: C. To evaluate the condition of insulation between the
winding and ground or other conductive parts
Rationale: An insulation-resistance tester applies a controlled DC test
voltage and measures resistance through the insulation system. A low
or deteriorating insulation resistance can indicate moisture,
contamination, aging, carbonization, or insulation damage.
5. A motor winding has acceptable insulation resistance to ground
but shows significantly different resistance values between its three
phase windings. What should the repairer suspect?
A. A possible winding imbalance, incorrect connection, or damaged
winding
B. Perfect winding symmetry
C. Excessive bearing grease only
D. Correct operation with no further investigation necessary
3
, Answer: A. A possible winding imbalance, incorrect connection, or
damaged winding
Rationale: Comparable phase-to-phase winding resistance is normally
expected in a properly constructed three-phase motor, allowing for
design and measurement tolerances. A substantial difference can
indicate an open or damaged conductor, poor connection, incorrect
winding configuration, or other winding defect.
6. Why is it important to record the original lead identification
before disconnecting a motor?
A. To determine the motor's paint color
B. To ensure the winding and terminal connections can be restored
correctly
C. To increase the motor's rated voltage
D. To eliminate the need for electrical testing after repair
Answer: B. To ensure the winding and terminal connections can be
restored correctly
Rationale: Motor leads can have multiple connection arrangements
depending on voltage, starting method, and winding configuration.
Accurate identification prevents phase-sequence errors, incorrect
voltage connections, reversed rotation, circulating currents, or
winding damage.
7. A motor shaft exhibits excessive radial movement during
inspection. Which component should receive particular attention?
A. Terminal block
B. Bearing assembly
C. Nameplate
D. Grounding conductor
4
