CFESA Electrical and Mechanical Systems 4

Question 1

A commercial dishwasher's wash pump motor trips its overload repeatedly. After resetting, it runs for 10 minutes before tripping again. What is the FIRST thing to inspect?

Accepted Answer

Check for a clogged wash arm or pump impeller causing excessive amp draw

Answer

A mechanical restriction like a clogged impeller increases the motor's amp draw significantly, causing the overload to trip after thermal buildup.

Question 2

What does it mean when a clamp-on ammeter reads current on the green (ground) wire of a piece of commercial food equipment?

Accepted Answer

A ground fault is present, causing current to return via the grounding conductor

Answer

Current flowing on the ground wire indicates a ground fault, where unintended current is finding its return path through the grounding conductor.

Question 3

Which type of transformer is used in commercial food equipment control circuits to step down 208V or 240V to 24V for control operations?

Accepted Answer

Step-down control transformer

Answer

A step-down control transformer reduces line voltage to a safe, low-voltage level (typically 24V) to power control boards, relays, and thermostats.

Question 4

A gear-driven commercial slicer produces a loud grinding noise only when the carriage is moving. The motor runs quietly at idle. What is the MOST likely cause?

Accepted Answer

Worn or damaged carriage drive gears or a dry carriage rail

Answer

Grinding noise that occurs only during carriage movement isolates the problem to the carriage drive mechanism — worn gears or a dry, rough rail.

Question 5

What is the purpose of a potential relay (also called a voltage relay) used in refrigeration compressor starting circuits?

Accepted Answer

To drop the start capacitor and winding out of the circuit once the motor reaches sufficient speed

Answer

A potential relay senses the back-EMF generated by the start winding and opens its contacts to remove the start capacitor once the motor approaches operating speed.

CFESA - Commercial Food Equipment Service Association Practice Test

CFESA - Commercial Food Equipment Service Association Practice Test

CFESA Electrical and Mechanical Systems 4