Page 176 - Power Quality in Electrical Systems
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158 Chapter Eleven
500%
400%
CBEMA
300% ITIC
Voltage SEMI F-47
200%
130%
140%
120% 110%
106%
100% 90%
87%
58% 70% 80%
50%
30%
0.2%
0%
0.001 0.01 0.1 10 100 1000 Cycles
1 ms 1/2 50 ms
Time 3 ms 8.33 ms 0.5 2 10 Seconds
20 ms
Figure 11.2 Power acceptability curves for computers. Comparison
of CBEMA ITIC and SEMI F47 curves [11.2].
[© 2005, IEEE, reprinted with permission]
350%
300%
Magnitude (% nominal) 200%
250%
150%
100%
50%
0%
1 us 10 us 100 us 1 ms 10 ms 100 ms 1 s 10 s
Disturbance duration (seconds)
Figure 11.3 A voltage disturbance profile at a commercial customer site.
Surges and sags during 2074 hours [11.5].
[© 1998, IEEE, reprinted with permission]
