DEC VT220 Technical Manual page 189

Table 9-1
Input Voltage Specifications (Cont)
Voltage
230 Vac
Specification
Transients
Nominal voltage
Minimum voltage
Maximum voltage
Input line current
Line frequency
Power factor
Inrush current
Peak inrush
Input power
Efficiency
Undervoltage
Overvoltage
Transients
Value
Low energy transient of 300 V peak
spike with no more than 0.2
watt-seconds of energy per spike;
High energy transient of 1 kV peak
spike with no more than 2.5
watt-seconds of energy per spike.
220 Vac-240 Vac
174 V rms
268 V rms
0.511. rms (max.)
47-63 Hz
(watts) -- (rms V
X
rms A)
>
0.55
Surge current at first application
of input voltage may be reached for
1/2 cycle of input line, with
repetitive peaks of exponentially
decaying amplitude for up to 10 more
cycles.
25 A (Thermisters cold)
120 watts (max.) at full rated dc
output load of 77 watts.
0.65 (min.) output power to input
power ratio.
Provides minimum of 5 millisecond
hold-up at 180 V rms during power
outage.
300 Vac for
1
second (max.)
Low energy transient of 300 V peak
spike with no more than 0.2
watt-seconds of energy per spike;
High energy transient of 1 kV peak
spike with no more than 2.5
watt-seconds of energy per spike.
9.2.2.1 +12
V
Start Up Circuit -- The +12
V
start up circuit
(Figure 9-5) consists of the following components/circuits.
• AC input transformer (T592)
• Rectifier (ES0l)
• Filter capacitors (C501 and CS02)
• +12
V
regulator components (E592, 0591, and 0502)
The +12
V
start up potential provides an operational potential for
the comparator within the overcurrent protect circuit. The +12
V
start up potential is also supplied to the pulse width modulator
where it provides initial power for operation of this circuit
until the +12 V dc circuit is operational.
9-6