SACA - Smart Automation Certification Alliance Mechanical Power Transmission Questions and Answers

Question 1

A motor operates at 1800 RPM and is connected to a simple gearbox. The drive gear on the motor shaft has 20 teeth, and the driven gear on the output shaft has 80 teeth. What is the approximate output speed of the gearbox?

Accepted Answer

450 RPM

Answer

The gear ratio is found by dividing the number of teeth on the driven gear by the number of teeth on the drive gear (80 / 20 = 4). This results in a 4:1 speed reduction. The input speed (1800 RPM) is then divided by the gear ratio (4) to determine the output speed (1800 / 4 = 450 RPM).

Question 2

Which of the following is a primary advantage of using a synchronous (timing) belt drive system compared to a standard V-belt drive?

Accepted Answer

Positive, slip-proof engagement for precise positioning

Answer

The key advantage of a synchronous belt is that its teeth mesh with the grooves of the sprockets, creating a positive engagement that prevents slipping. This is crucial for applications that require precise timing and position control, which V-belts cannot guarantee as they rely on friction and can slip under load.

Question 3

What is the primary function of a flexible shaft coupling, such as a jaw or grid coupling, in a mechanical power transmission system?

Accepted Answer

To accommodate for minor parallel and angular misalignment between shafts

Answer

Flexible couplings are specifically designed to connect two shafts while allowing for small amounts of misalignment (angular, parallel, or axial). This prevents premature wear and failure of connected components like bearings, which would be subjected to high stress if a rigid coupling were used with misaligned shafts.

Question 4

During a routine inspection, a technician notes a loud, high-pitched grinding noise originating from a pillow block bearing on a conveyor line. The noise increases with the speed of the conveyor. Which of the following is the most likely cause?

Accepted Answer

Contamination or lack of lubrication in the bearing

Answer

Grinding, whining, or squealing noises that change with rotational speed are classic symptoms of a failing rolling-element bearing. This typically indicates a lack of lubrication, contamination with foreign particles, or physical damage to the bearing's internal components.

Question 5

When performing preventative maintenance on a roller chain drive, which of the following are the two most critical parameters to check and adjust to ensure maximum operational life?

Accepted Answer

Chain lubrication and proper tension

Answer

Proper lubrication is essential for reducing friction and wear between the pins, bushings, and rollers of the chain. Correct tension is also critical; a chain that is too tight causes excessive bearing load, while a chain that is too loose can whip, jump teeth, and wear rapidly.

SACA - Smart Automation Certification Alliance Practice Test

SACA - Smart Automation Certification Alliance Practice Test

SACA - Smart Automation Certification Alliance Mechanical Power Transmission Questions and Answers