EGSA Electrical Systems Troubleshooting 2

Question 1

A generator shows high AC voltage output but the frequency is correct. What is the most likely cause?

Accepted Answer

Faulty AVR

Answer

Incorrect governor setting

Answer

Open phase winding

Answer

Worn brushes

Question 2

When troubleshooting a generator that trips on overcurrent, which test should be performed first?

Accepted Answer

Megohmmeter test on windings

Answer

Fuel system pressure check

Answer

Governor actuator test

Answer

Battery load test

Question 3

A transfer switch fails to transfer to the emergency source after generator start. The most likely cause is:

Accepted Answer

Faulty sensing relay in the transfer switch

Answer

Low coolant level

Answer

Incorrect fuel octane rating

Answer

Loose alternator belt

Question 4

What does a high resistance measurement across a closed circuit breaker indicate?

Accepted Answer

Damaged or pitted contacts

Answer

Correct contact seating

Answer

Overloaded circuit

Answer

Correct torque on connections

Question 5

A three-phase generator produces balanced voltage but one phase has no load current. What is the most likely fault?

Accepted Answer

Open circuit on the load side of that phase

Answer

Faulty AVR potentiometer

Answer

Unbalanced rotor field

Answer

High ambient temperature

Question 6

Which instrument is used to measure insulation resistance in generator windings?

Accepted Answer

Megohmmeter

Answer

Clamp-on ammeter

Answer

Power factor meter

Answer

Frequency counter

Question 7

A diesel generator hunts (surges) at no-load but stabilizes under load. The most likely cause is:

Accepted Answer

Worn or sticking governor linkage

Answer

Faulty AVR

Answer

Low fuel level

Answer

Incorrect oil viscosity