EGSA Automatic Transfer Switch Function 2

Question 1

What is the purpose of the 'time delay neutral' (TDN) setting in an ATS?

Accepted Answer

To pause load transfer in the neutral position between sources

Answer

Time delay neutral pauses the ATS in the open (neutral) position during transfer to allow inductive loads to de-energize before connecting to the alternate source.

Question 2

Which ATS class rating is specifically required for life safety systems per NFPA 110?

Accepted Answer

Class B

Answer

NFPA 110 requires Class B ATS for life safety systems, which must transfer within 10 seconds of utility failure.

Question 3

What does the term 'in-phase monitoring' refer to in an ATS application?

Accepted Answer

Synchronizing generator and utility voltage phase angle before closed-transition transfer

Answer

In-phase monitoring ensures the generator and utility are at the same phase angle at the moment of closed-transition transfer, preventing a voltage transient from paralleling out-of-phase sources.

Question 4

A three-pole ATS differs from a four-pole ATS primarily in how it handles the:

Accepted Answer

Neutral conductor during transfer

Answer

A four-pole ATS switches the neutral conductor along with the three phase conductors, which is required when the generator has a separately derived system with its own neutral-to-ground bond.

Question 5

What is the primary reason for the 'time delay to engine start' (TDES) setting on an ATS?

Accepted Answer

To prevent nuisance starts from momentary utility outages

Answer

TDES prevents unnecessary generator starts during brief utility interruptions such as momentary dips, blinks, or automatic recloser operations.

(EGSA) Electrical Generating Systems Association Certified Practice Test

(EGSA) Electrical Generating Systems Association Certified Practice Test

EGSA Automatic Transfer Switch Function 2