Furman AR-PRO - Page 3

AR-PRO – AC LINE VOLTAGE REGULATOR
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The AR-PRO is intended to protect computer, audio,
video and other electronic equipment from problems
caused by AC line voltage irregularities - sags, brown-
outs or over voltages that can cause sensitive digital
equipment to malfunction, or, in extreme cases, to
sustain damage. It accepts single phase input AC
voltages anywhere within two capture ranges, 88
to 134V (low range) or 170 to 264V (high range) and
converts them to the North American standard 120 volts
(or, on model AR-PRO-J, to 100V). Voltages outside the
ranges may be converted to usable levels, depending
on how far out of range they are and what is considered
usable. For example,
any
voltage from 80 to 267 will be
converted to 120V ±4%. See Figure 1 below.
The AR-PRO can handle loads totaling up to 30
amperes as long as the input voltage is equal to or
above 120 volts (low range) or 240 volts (high range).
For voltages below those levels, its capacity must be
derated at approximately one-quarter ampere per volt.
See Figure 2 below.
In live performance situations, where each act requires
a special AC confi guration, accidental connection to
incorrect AC voltages occurs surprisingly often with
disastrous consequences.
Because of its dual range capability, the AR-PRO can
protect against a catastrophic error in AC mains wir-
ing. This feature also makes the AR-PRO ideal as a
component of a power distribution scheme suitable
for worldwide use, accommodating national voltages
of 100, 120, 220, 240, or others, with equal ease and
without the need for readjustment.
The AR-PRO uses a design based on a 25-tap toroidal
autotransformer. The toroidal design assures minimal
leakage of stray magnetic fi elds in a highly effi cient,
compact package. The AR-PRO’s circuitry monitors
the incoming line voltage with each cycle. If a volt-
age change requires that a different tap be selected,
the new tap is electronically switched in precisely at
the zero-crossing, to avoid distorting the AC waveform.
If necessary, the AR-PRO can switch taps as often as
once each cycle. Most commercial voltage regulators
using multiple-tapped transformers switch taps with
relays at uncontrolled times, thereby
creating
voltage
spikes! And unlike voltage regulators that employ Ferro
120
122
124
126
128
130
132
114
116
118
110
112
Output Voltage
-No Output-
208
Input Voltage
108 112 116 12010492 96 100 124 128 132 136 142888480
160 176 184 192 200 216 224 232240 248256264
TWO VOLTS PER DIVISION FOUR VOLTS PER DIVISION
168
Low Range�
Input Voltage
High Range�
Input Voltage
208
Input Voltage
108 112 116 12010492 96 100 124 128132 136
142
888480 160 176 184 192 200 216 224 232 240 248256264
TWO VOLTS PER DIVISION FOUR VOLTS PER DIVISION
168
Low Range�
Input Voltage
High Range�
Input Voltage
29
30
27
28
25
26
Output Current
24
23
22
21
20
Functional Range
Regulation Range
Regulation Range
Functional Range
FIGURE 1: OUTPUT VOLTAGE VS. INPUT VOLTAGE
FIGURE 2: AVAILABLE OUTPUT CURRENT VS. INPUT VOLTAGE
AR-PRO GRAPHS