1) Which type of enclosure is provided for DC motors used in coal handling plants?
a. Screen protected
b. Open type
c. Totally enclosed fan cooled
d. Drip proof
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Answer
Explanation
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ANSWER: Totally enclosed fan cooled
Explanation:
No explanation is available for this question!
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2) What is meant by equaliser bus?
a. The bus connecting series fields in parallel
b. The bus connecting series fields in series
c. The bus connecting shunt fields in parallel
d. The bus connecting shunt fields in series
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Answer
Explanation
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ANSWER: The bus connecting series fields in parallel
Explanation:
No explanation is available for this question!
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3) Which among the following applications uses ward Leonard method of speed control?
a. Rolling mills
b. Colliery winding motor
c. Lifts and elevators
d. Only a and c
e. All of these
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Answer
Explanation
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ANSWER: All of these
Explanation:
No explanation is available for this question!
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4) What is the voltage characteristic of a differential compound DC motor?
a. Rising
b. Drooping
c. Flat
d. Exponential
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Answer
Explanation
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ANSWER: Drooping
Explanation:
No explanation is available for this question!
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5) At what temperature is the drying out procedure carried out in a DC motor?
a. 50 ° C
b. 100 ° C
c. 150 ° C
d. 200 ° C
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Answer
Explanation
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ANSWER: 100 ° C
Explanation:
No explanation is available for this question!
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6) Which among these is common defect in a Commutator?
a. Over Mica
b. High Copper bar
c. Sharp edges of copper bars
d. Only a and b
e. All of these
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Answer
Explanation
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ANSWER: All of these
Explanation:
No explanation is available for this question!
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7) On what factor does the commutation depend?
a. Brush grade
b. Condition of Commutator surface
c. Position of interpoles and magnetic flux
d. All of these
e. None of these
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Answer
Explanation
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ANSWER: All of these
Explanation:
No explanation is available for this question!
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8) Which among these is the cause of sparking at brushes in DC motor?
a. Defective brushes
b. Defect in Commutator
c. Excessive load
d. Only a and b
e. All of these
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Answer
Explanation
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ANSWER: All of these
Explanation:
No explanation is available for this question!
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9) Which material is used for the manufacture of brushes in DC motors?
a. Graphite
b. Lead
c. Copper
d. All of these
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Answer
Explanation
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ANSWER: Graphite
Explanation:
No explanation is available for this question!
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10) Which among these DC motor(s) is / are having lower full load torque?
a. Series motor
b. Shunt motor
c. Cumulative motor
d. Differential motor
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Answer
Explanation
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ANSWER: Shunt motor
Explanation:
No explanation is available for this question!
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