Open circuited armature coil of a D.C. machine is________________?
Correct answer: C. both A. and (b)
- A. identified by the scarring of the commutator segment to which open circuited coil is connected
- B. indicated by a spark completely around the commutator
- C. both A. and (b)
- D. none of the above
Explanation
An open armature coil interrupts current transfer at its associated commutator bars, producing scarring or burning there and abnormal sparking that may extend around the commutator. Hence both listed indications are used for detection.
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