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Section 6: Automatic Transfer Switches

Task 41.) Define theory and principles of ATS operations

a Automatic transfer of power
b Transfer load to available source
c Sequence--Senses loss of power; starts generator; transfers to generator source; senses
return of normal sources; transfers back; shuts generator off

Reference:
EGSA (2015). On-Site Power Generation Reference Book, Fifth Edition. Boca Raton, Florida:
Electrical Generating Systems Association. Chapters 29, 30

Task 42.) Identify types of ATS

a Option--2, 3 and 4 pole, in phase,
b By-pass isolation
c Closed transition
d Open transition
e Delayed transition
f Soft load

Reference:
Wildi, Theodore (2004). Electrical Machines, Drives, and Power Systems, 6th Edition. Upper Saddle
River, New Jersey: Prentice-Hall. Chapter 26

EGSA (2015). On-Site Power Generation Reference Book, Fifth Edition. Boca Raton, Florida:
Electrical Generating Systems Association. Chapters 29, 30

Task 43.) Verify phase rotation on ATS

a Confirm alternate source matched the preferred source rotation
b Determine consequences of out of phase

Reference:
Wildi, Theodore (2004). Electrical Machines, Drives, and Power Systems, 6th Edition. Upper Saddle
River, New Jersey: Prentice-Hall. Chapter 8

EGSA (2015). On-Site Power Generation Reference Book, Fifth Edition. Boca Raton, Florida:
Electrical Generating Systems Association. Chapters 29, 30

Page 43 - EGSA Apprentice Certification Program Study Guide