NCCER Millwright Practice Exam 2025 - Free Millwright Practice Questions and Study Guide

The roller conveyor is designed to utilize gravity as a primary means of moving materials from one point to another. It consists of a series of parallel rollers mounted horizontally on a frame, allowing items placed on the conveyor to roll along the surface with minimal manual effort. This setup is particularly effective for transporting items down slopes, where gravity assists in the movement, making it energy-efficient and cost-effective compared to powered systems.

In contrast, powered conveyors rely on motors and belts to move materials, often requiring a constant source of energy for operation. Belt conveyors employ a continuous loop of material that moves regardless of the item's weight, and while they can incline or decline, they do not primarily rely on gravity. Slat conveyors use slats mounted on chains to transport products, which requires mechanical power to operate regardless of gravity. Therefore, the roller conveyor stands out as the type that typically uses gravity to aid movement effectively.