Page 218 - Power Quality in Electrical Systems

200 Chapter Thirteen

Automatic
transfer
Normal switch
source
Loads: Lights Motors, Heaters, etc.

Emergency
source
Figure 13.10 Normal/emergency sources. Automatic transfer switch [13.5].

Summary
Standby power equipment provides the means to improve the reliabil-
ity of the utility electric power supply to critical load equipment.
Alternate feeders and E/G sets utilizing transfer switches are the prin-
cipal means of providing both power and standby power to UPSs, health
care facilities, and telecommunications systems. The design requires
consideration of all aspects of the existing utility supply and the desired
objectives of the high-reliability system.

References
[13.1] A. Kusko, Emergency/Standby Power Systems, McGraw-Hill, New York, 1989.
[13.2] ANSI/IEEE 446-1995, “Recommended Practice for Emergency and Standby Power
Systems for Industrial and Commercial Applications”.
[13.3] NFPA 110-2005, “Standard for Emergency and Standby Power Systems”.
[13.4] NFPA 10-2005, “National Electric Code”.
[13.5] EGSA, On-Site Power Generation Reference Book, 4th edition, 2002.
[13.6] NEMA ICS 2-447, “AC Automatic Transfer Switches”.
[13.7] UL1008, Standard for Automatic Transfer Switches, 4th edition.