A belt drive on a motor driven fan has a drive sheave of 3" on the motor. The sheave of the fan shaft has a diameter of 5". Calculate the fan speed if the motor is spinning at 1720RPM.

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Multiple Choice

A belt drive on a motor driven fan has a drive sheave of 3" on the motor. The sheave of the fan shaft has a diameter of 5". Calculate the fan speed if the motor is spinning at 1720RPM.

Belt drive speed follows the inverse ratio of pulley sizes. The driven speed equals the motor speed times the driving pulley diameter divided by the driven pulley diameter. With a 3" driving pulley and a 5" driven pulley, the fan speed is 1720 × (3/5) = 1032 RPM. Since the drive pulley is smaller than the driven pulley, the fan slows down accordingly. The result is 1032 RPM.

Belt drive speed follows the inverse ratio of pulley sizes. The driven speed equals the motor speed times the driving pulley diameter divided by the driven pulley diameter. With a 3" driving pulley and a 5" driven pulley, the fan speed is 1720 × (3/5) = 1032 RPM. Since the drive pulley is smaller than the driven pulley, the fan slows down accordingly. The result is 1032 RPM.

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