Maintenance Technician Practice Test

A gear reducer has an input gear with 20 teeth and an output gear with 40 teeth. Therefore:

1. The output speed will be greater than input speed, and output torque will be smaller than input torque.

2. The output speed will be smaller than input speed, and output torque will be greater than input torque.

3. The output speed will be greater than input speed, and output torque will be greater than input torque.

4. The output speed will be smaller than input speed, and output torque will be smaller than input torque.

The correct answer is: The output speed will be smaller than input speed, and output torque will be greater than input torque.

In a gear reducer system, the relationship between the input and output gears is crucial for understanding how speed and torque are altered. When the input gear has fewer teeth than the output gear, as in this case where the input has 20 teeth and the output has 40 teeth, the output gear rotates slower than the input gear. This is because it takes more revolutions of the input gear to turn the output gear once; specifically, for every complete rotation of the input gear, the output gear will only complete half a rotation. Thus, the output speed decreases. As for torque, the principle of conservation of energy applies in mechanical systems. While speed is reduced, torque is increased because the power (the product of speed and torque) remains roughly constant (ignoring losses). Therefore, since the output gear is larger, it experiences a greater torque. In this scenario, the output torque will indeed be greater than the input torque due to the relationship of the gear teeth. This relationship allows the system to provide higher torque at the output, which is particularly useful in applications requiring high force, such as lifting or moving heavy loads, despite operating at a lower speed. Consequently, the conclusion is that the output speed will be smaller than the input speed, and