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AC Line Voltage Reg u la tor Owners Manual
AR-Series Features
Output capacity 30 amps
Output voltage can be changed to 220V or 240V with
internal jumper
Usable range for most equipment is an ad di tion al 10% above
and below the capture ranges shown in Speci cations (pg. 4)
One twist lock inlet and one regulated, con di tioned
twistlock outlet on rear panel
Eight-tap toroidal autoformer
10-LED bargraph Input Voltage meter
10-LED bargraph true RMS reading Output Current meter
Extreme overvoltage/undervoltage causes in stant
shutdown, protecting equip ment
Extreme Voltage Shutdown indicator LED
Output In Regulation in di ca tor
Fast-acting user-accessible circuit breaker pro tects against
overload or shorts. Also acts as ON/OFF switch.
Low stray magnetic eld
Low noise, variable speed fan provides cooling for heavy-
duty, continuous op er a tion
Rugged, two-space rack unit weighs only 49 lbs. (22 kg.)
Determine the Correct Voltage
Is 240V the correct voltage for your application?
The AR-2330D is factory set for 240V output. All equipment
should be checked rst, to be sure that 240V is a suit able volt-
age (normally listed near the power cord). If a lower volt age is
desired, the AR-2330D should have its internal jumper changed
to 220 or 230 volts. If in doubt, consult your dealer.
AC Line Voltage Reg u la tor
Owners Manual
General Information
Thank you for choosing a Furman AR-2330D AC Line Volt age
Reg u la tor. An AR-Series regulator is the perfect ac ces so ry to any
au dio, video, or computer rackmount system re quir ing clean,
l tered, and regulated AC power for optimum op er a tion.
Furman Voltage Regulators are intended to protect sensitive
electronic equipment from problems caused by AC line voltage
irregularitiesbrownouts or overvoltages that can cause audio
ton al changes, digital equipment malfunction (such as loss of
MIDI pro grams or other data), or, in extreme cases, permanent
dam age. The AR-2330D accepts input voltages over a wide AC
volt age range (see table above) converts them to, and stabilizes
them at ±10V for 240V output. (The output voltage can be changed
to 220V or 230V with an internal jumper.) Voltages approximately
±10% beyond the AR-2330Ds range may be converted to usable
levels, depending on the requirements of the equipment. See
Figure 1.
The AR-2330D has one twistlock inlet and one twistlock out let
on the rear panel. The outlet is regulated, spike-suppressed, and
EMI/RFI ltered. There are no controls except an on-off break er
switch.
Limitations: The AR-2330D is for use with AC voltage only.
DC voltages should never be applied to it. Also, it does not change
or regulate line frequency. The output frequency will always be
the same as the incoming line fre quen cy.
AR-2330D front view
MODEL AR-2330D
AR-2330D rear view, shown with optional RRM-2 rear rack ears
Furman Sound, Inc.
1997 South McDowell Blvd.
Petaluma, California 94954-6919 USA
Phone: 707-763-1010
Fax: 707-763-1310
www.furmansound.com
E-mail: info@furmansound.com Output Current Monitoring
The AR-2330Ds ammeter reads AC current from 0 to 30
amps, in 3-amp steps. Currents above the 30 amp limit read red,
with yel low in di cat ing a warning zone. Please keep in mind that
the am me ter may not read at all if the total load connected is
less than 2 amps (240 watts). This is a likely oc cur rence if
only rel a tive ly low pow er, sig nal processing-type equipment is
connected. With the master switch off, the ammeter can still
read, but will only do so if equip ment drawing at least 2 amps is
connected to the un switched outlet.
The ammeter is capable of giving a re li able in di ca tion of
current drawn by all kinds of equipment, thanks to its true-RMS-
read ing circuitry. This means that loads like pow er ampli ers, which
are primarily ca pac i tive and in duc tive, will read as accurately as
purely resistive loads like heaters. Ammeters that respond only to
average AC cur rent may vary widely from RMS reading meters.
Design
The AR-2330D uses a design based on an eight-tap toroidal
au to form er. The toroidal design assures minimal leakage of
stray mag net ic elds, and, because of its high ef ciency, a very
compact size for its rating. The Voltage Regulators circuitry mon-

i tors the incoming line voltage with each cycle, comparing it to
an ex treme ly precise voltage reference, accurate to ±0.15%. If a
voltage uc tu a tion requires that a different tap be selected, the
new tap is elec tron i cal ly switched ex act ly at the zero-crossing,
to avoid distorting the AC waveform. If nec es sary, it can switch
taps as often as once each cycle. Some com mer cial voltage
regulators using mul ti ple-tapped trans form ers switch taps at
uncontrolled times, there by cre at ing voltage spikes and clicks
that can leak into the audio! Hys ter e sis in the switch ing circuits
avoids chat ter or un nec es sary switch ing back and forth between
adjacent taps. And un like voltage regulators that em ploy
ferro-res o nant trans form ers, the Fur man AR-Series is not
sensitive to small er rors in line fre quen cy, making them ideal for
use with gen er a tors.
Supply Cable Wir ing
The AR-2330Ds rear pan el provides a NEMA
L14-30P male inlet connector; a NEMA L14-30 cord mount ed
fe male con nec tor is in clud ed with the unit. Please refer to the
Rear View wiring diagram at right.
Wire the two hot leads (black) to X and Y (black, and white or
red), and the equip ment ground (green) to G.
It is essential that all equip ment pow ered by an AR-2330D be
properly ground ed!
Never cut off the power cord ground pin or use a cheat er
adap tor on any of your equipment!
Installation
The AR-2330D is designed for mounting in a standard
19-inch rack. Because of its weight, the best position for it
is at the bottom of the rack. Its toroidal transformer minimizes
magnetic leak age, but nevertheless, due to its high capacity,
it can radiate an ap pre cia ble magnetic field. Therefore, we
recommend that it not be po si tioned adjacent to sen si tive, low
level signal processors, es pe cial ly mic preamps, mixers, tape
recorders, etc. Power amps may be more suit able rack neigh-

bors. As with any rackmount equip ment, be sure to use 10-32
machine screws for mount ing in the racks tapped holes, and to
avoid mar ring the front panel n ish, use plas tic wash ers un der
the screw heads.
Maximum Load
The AR-2330D can handle loads totalling up to 30 amperes
as long as the input voltage is equal to or above the selected
output voltage (240V). For voltages below that level, its ca pac i ty
must be derated at approximately .15 amperes per volt. See
Figure 2. To cope successfully with worst-case brown out
conditions, you should take this into account. An easy way to
calculate this yourself is to multiply input voltage by maximum
input current (ex. 200V x 30A = 6000 watts) to get the max i mum
pow er the unit can han dle at this input volt age. Then divide this
number by the out put volt age (6000/240 = 25 amps). If your load
draws any more than 25 amps, it will cause the input current to
rise above 30 amps and will then trip the break er.
Extreme Voltage Protection
The AR-Series includes special circuitry to sense over- and
un der-voltages and positively shut down the output before
possible damage is done. For the AR-2330D, overvoltages are
those over 300V. When the input voltage exceeds that limit, the
power will cut off. It will come back on automatically when the
ov er volt age is reduced to 285V or lower. The red LED labelled
EX TREME VOLT AGE SHUT DOWN in di cates the shut down
condition. The output is also shut down for extremely low input
volt ag es, less than 158V.
To provide additional protection against a catastrophic high
voltage condition, voltages over approximately 300V may cause
an in ter nal fuse to blow. This is a 250 mA/250V fuse and requires
removal of the top cover. If this unlikely condition occurs, please
remove power from the unit rst.
Fuses and Circuit Breakers
There are three fuses and one fast-acting magnetic circuit
break er in the AR-2330D.
1. A precision 30 amp magnetic circuit breaker is used as the
on/off switch. If the input to the unit exceeds 30 amps, the break er
will trip. Be sure to reduce your load before re-powering the unit,
or it will likely trip again. Refer to the previous section Maximum
Load if you are uncertain why the breaker is tripping, or want to
understand the relationship between input voltage and current vs.
output voltage and current.
2. A fast-blow 250 mA amp fuse is located inside the unit, as
previously mentioned. To replace it, the unit must be com plete ly
dis con nect ed from all power and removed from its rack. The six
hex head screws and one Allen head screw holding the top cov er
must be re moved.
3. A Fast Blow 1 amp fuse protects a low current aux