NEIEP Mechanics Practice Exam

What mechanism is affected when changing the speed of a door in a linked system?

1. The motor efficiency

2. The swinging arc of the arm

3. The load capacity of the door

4. The operation of the secondary link

The correct answer is: The operation of the secondary link

When changing the speed of a door in a linked system, the operation of the secondary link is influenced because the movement of the primary component (the door) directly impacts any connected mechanisms. The secondary link, which may be a part of the system that assists in the movement or control of the door, will respond to changes in speed. For instance, if the door opens or closes faster, the secondary link must accommodate this change in speed to ensure smooth and coordinated operation. This can involve adjustments in timing, tension, or alignment within the linkage system to maintain proper function. In contrast, motor efficiency, the swinging arc of the arm, and load capacity of the door typically remain unaffected by changes in speed, as these factors are more related to the inherent design and capabilities of the motor and structural components rather than the speed of operation itself. Therefore, while these other factors are important in the overall system, they do not directly change in response to a change in door speed as the secondary link does.