Directions: It consists of two statements, one labeled as the ‘Statement (I)’ and the other as ‘Statement (II)’. Examine these two statements carefully and select the answer using the codes given below:

Statement (I): When the armature-iron of a dc machine rotates, it goes through the influence of the north and the south poles, thus causing cyclic variations of the linked magnetic flux and resulting in the occurrence of hysteresis loss in the armature core.

Statement (II): The laminated armature construction limits the hysteresis loss to a lower value.

This question was previously asked in
ESE Electrical 2015 Paper 2: Official Paper
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  1. Statement (I) and Statement (II) are individually true and statement (II) is the correct explanation of statement (II)
  2. Statement (I) and Statement (II) are individually true but statement (II) is not the correct explanation of statement (I)
  3. Statement (I) is true but statement (II) is false
  4. Statement (I) is false but statement (II) is true

Answer (Detailed Solution Below)

Option 3 : Statement (I) is true but statement (II) is false
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Detailed Solution

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Hysteresis losses: When the armature-iron of a dc machine rotates, it goes through the influence of the north and the south poles, thus causing cyclic variations of the linked magnetic flux and resulting in the occurrence of hysteresis loss in the armature core.

Hysteresis losses can be minimized by using material having least hysteresis loop area. The laminated armature construction limits the eddy current losses to a lower value but not hysteresis loss.

Therefore, Statement (I) is true but statement (II) is false.
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