NCCER 26410 MOTOR OPERATION
AND MAINTENANCE EXAM
A Lovejoy® coupling can be used to reduce . - Correct Answers -motor-to-load vibration
Which of the following is the BEST instrument for testing for a grounded coil? - Correct
Answers -Continuity tester
NEMA's usual service conditions include a frequency variation of NOT more than . -
Correct Answers -5% of the nameplate frequency
Endplay adjustment is generally done on large motors with __________. - Correct
Answers -adjustable bearings
If excessive vibration is detected in the driven equipment during motor startup, it may be
the result of a(n) . - Correct Answers -imbalanced load
Which of the following factors affects the frequency and thoroughness of motor
maintenance and testing? - Correct Answers -Nature of service
When a motor is powered down, unusual bearing noise may be detected by using a(n) .
- Correct Answers -stethoscope
The recommended minimum polarization index for an AC motor is________. - Correct
Answers -2
A motor's rotating speed can be determined using a(n) - Correct Answers -tachometer
Absorption current consists of polarization current and . - Correct Answers -electron drift
An autotransformer is one of the methods used to . - Correct Answers -reduce startup
current
The useful life of a squirrel cage induction motor depends largely on the condition of its
_________. - Correct Answers -insulation
The loss of a single phase of a polyphase motor can cause_________. - Correct
Answers -failure of the remaining phase windings
The first time a motor is started, it should be allowed to run - Correct Answers -without
load for 1 hour
AND MAINTENANCE EXAM
A Lovejoy® coupling can be used to reduce . - Correct Answers -motor-to-load vibration
Which of the following is the BEST instrument for testing for a grounded coil? - Correct
Answers -Continuity tester
NEMA's usual service conditions include a frequency variation of NOT more than . -
Correct Answers -5% of the nameplate frequency
Endplay adjustment is generally done on large motors with __________. - Correct
Answers -adjustable bearings
If excessive vibration is detected in the driven equipment during motor startup, it may be
the result of a(n) . - Correct Answers -imbalanced load
Which of the following factors affects the frequency and thoroughness of motor
maintenance and testing? - Correct Answers -Nature of service
When a motor is powered down, unusual bearing noise may be detected by using a(n) .
- Correct Answers -stethoscope
The recommended minimum polarization index for an AC motor is________. - Correct
Answers -2
A motor's rotating speed can be determined using a(n) - Correct Answers -tachometer
Absorption current consists of polarization current and . - Correct Answers -electron drift
An autotransformer is one of the methods used to . - Correct Answers -reduce startup
current
The useful life of a squirrel cage induction motor depends largely on the condition of its
_________. - Correct Answers -insulation
The loss of a single phase of a polyphase motor can cause_________. - Correct
Answers -failure of the remaining phase windings
The first time a motor is started, it should be allowed to run - Correct Answers -without
load for 1 hour
