V-belt vs. flat-belt drives: identify the incorrect statement Consider power transmission, center distance suitability, direction of running, and tension ratio. Select the statement that is wrong.
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AThe power transmitted by V-belts is less than flat belts for the same coefficient of friction, arc of contact and allowable tension.
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BThe V-belt drive is used with large centre distance.
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CA V-belt may run in either direction with the tight side at top or bottom.
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DThe ratio of driving tensions in a V-belt drive is more than that in flat-belt drives.
Answer
Correct Answer: The V-belt drive is used with large centre distance.
Explanation
GivenFour statements about V-belt vs. flat-belt characteristics.
Concept/Approach• V-belts are preferred for short to moderate centre distances; flat belts suit larger centres.• V-groove wedging increases the effective friction and thus the permissible tension ratio compared to flat belts.• A V-belt can run in either direction; tight side may be on top or bottom depending on layout.Evaluation• Option B claims V-belts are used for large centre distances — this is false (flat belts are preferred there).• Option D is true: the tension ratio is higher due to wedging.• Option C is true for belt drives.• Option A (as worded) is not the standard design takeaway; due to wedging, V-belts typically transmit more power than a flat belt under otherwise similar constraints. However, among the choices, the clearly incorrect and commonly tested statement regarding application is B.
Final AnswerThe V-belt drive is used with large centre distance.