Page 240 - Power Quality in Electrical Systems
P. 240
222 Index
Protection: Reverse-rotating airgap fields, 42
of ASDs, 183–188 Ripples:
equipment for, 44 DC waveform with, 50
of induction motors, 176–177 peak-peak, 50
in passive filters, 95 pulsating waveforms with, 52
Protective relays, 2 triangular, 50–51
Pulsating waveforms, 51–52 Rms (see Root-mean square)
Pulse-width modulated (PWM) inverters: Root-mean square (rms), 47–48
SCRs for, 132 of DC waveforms, 50
series converter as, 149 piecewise calculation for, 52, 53
for six-pulse rectifiers, 115 of pulsating waveforms, 51, 52
switch mode power supplies, 99 of pure sine wave, 49
Pure sine wave, 45, 49 of square waveforms, 49, 50
Push-pull forward converters, 103 of THD, 53
PWM inverters (see Pulse-width of triangle waveforms, 52
modulated inverters) of triangular ripples, 50
Run time, 133
Quality (see Power quality)
S3K2U series, 134
Rating, in passive filters, 95 Sags (voltage sag, voltage dips), 7, 8,
Reactors: 25–29, 41
harmonics affecting, 44 analysis of, 27, 29–30
line, 10, 79–81 defined, 7
Reboot, computer, 1 distribution of, 112
Rectifiers, 3–6 PCs affected by, 160–161
of ASDs, 178 sensitivity to, 117
bridge, 4 sources of, 7
full-wave, 36–37 SAIDI (System Average Interruption
IGBTs in, 187 Duration Index), 107
polyphase, 75 Saturation, 73
silicon-controlled rectifier,131–132 SCR (short-circuit ratio), 78
single-phase, 35, 36–37, 64–72 SCR (silicon-controlled rectifier),
six-pulse, 4, 69–70, 115 131–132
three-phase, 4, 35, 40, 55–58 Search coils, 204
twelve-pulse, 70–71, 121, 178 SEMI F47 curve, 18, 20, 156
voltage-doubler diode, 148 Semiconductor logic, 163
Reduced voltage starters, 10 Semi-conductor processing equipment,
Redundancy, 110 156
Regulators: Sensitivity:
AVR, 134 of PCs, 160–161
voltage, 197 to sags, 117
Relay(s): Sensors, 163
AC (see AC contactors and relays) Series converter, 149
DC, 170 Series resonant filters, 85–87
failure of, 165–166 Series-tuned filters, 88–90
protective, 2 Servers, UPSs with, 191
Relay logic, 163 Shielded isolation transformers, 10
Relay transformers, 5 Short-circuit ratio (SCR), 78
Reliability: Short-term energy storage, 137
correction methods for, 113 Shunt converters, 149
of standby power system, 189 Shunt passive filters, 81–87
Resistive load (“burden”), 207 Shutdown, computer, 1
®
Restart, 184 Silicon 120 kVA, 135
