The three main parts of an excavator are:

1. The Boom: The boom is the long, vertical arm of the excavator that extends from the machine's main body. It provides the primary lifting and digging capabilities. The boom can be raised and lowered to control the digging depth and can be moved up and down to reach different heights. It plays a crucial role in lifting and moving heavy objects during construction or excavation work.

2. The Stick (Dipper Arm): The stick, also known as the dipper arm or dipper stick, is an intermediate component that connects to the boom at one end and holds the bucket at the other end. The stick is responsible for the horizontal extension and retraction of the bucket. By adjusting the length of the stick, the operator can control the excavator's reach, allowing it to access areas that are farther away from the machine's base.

3. The Bucket: The bucket is the attachment located at the end of the stick. It comes in various sizes and shapes, depending on the specific job requirements. The bucket is used for digging, scooping, and loading materials such as soil, rocks, debris, and other loose materials. It can be replaced with different types of attachments for various tasks, making the excavator a versatile piece of equipment.

These three main parts, along with the hydraulic cylinders and other components, work together to give an excavator its digging, lifting, and material-handling capabilities. The operator can control the movement of these parts using the machine's hydraulic system, allowing for precise and efficient excavation work.