What is the proper belt slack halfway between the hubs of a belt drive?

The proper belt slack halfway between the hubs of a belt drive is typically around 1/2 to 3/4 inches. This range allows for sufficient tension in the belt to ensure that it operates efficiently without excessive wear or slippage.

Having the correct amount of slack is important because too little slack can put undue stress on the motor and the belt itself, while too much slack can lead to slippage and inefficient power transfer. In this range, the belt can flex adequately, accommodating for expansion due to heat or vibration during operation, which contributes to the overall reliability and longevity of the belt drive system.

Other ranges of slack, such as those specified in the other answer choices, would not provide the same balance of tension and flexibility required for optimal performance in most belt drive applications. Therefore, the 1/2 to 3/4-inch slack is deemed the most appropriate for ensuring the belt operates effectively under typical conditions.