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Introduction
Congratulations on your purchase of a Furman PS-PRO Power Conditioner/
Sequencer. The PS-PRO is one of Furman’s top-of-the-line PRO Series, offering
maximum protection from the AC line hazards faced by delicate analog and digital
pro audio and video equipment.
The PS-PRO is a power sequencer, meaning it is capable of powering a rack full
of equipment in three steps separated by timed delays. It is useful whenever various
kinds of equipment must be powered up or down in groups, rather than all simulta-
neously. In audio systems, sequenced powering is often necessary to allow turn-on
transients from low level amplifiers and processors to settle down before any power
amps are turned on, because simultaneous powering would result in a loud, annoy-
ing, and potentially destructive “pop” reaching the speakers. And in any large system
whose components present an inductive load to the AC line (including electric mo-
tors, power supplies, and power amplifiers of all kinds), sequenced
powering can avoid excessive inrush currents that can cause circuit breakers to trip
even though the steady-state currents are not excessive. Power sequencing is par-
ticularly suited to applications where large installations must be switched by inexpe-
rienced personnel.
The PS-PRO is controlled by a front panel key-operated switch to provide
security from non-authorized users tampering with the system. The switch has three
positions: OFF, REM, and ON, allowing for local or remote control. With remote con-
trol, one or more PS-PRO’s may be installed in remote locations with on/off control
and LED monitoring via low-voltage control wires.
Besides its power sequencing capabilities, the PS-PRO contains many other con-
ditioning and protection features. Both aspects of its functioning will be
discussed in the next sections.
PS-PRO Features
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20 amp (2400 watt) rating handles even the largest amplifiers
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Export series (16 amps, 3600 watts)
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Multiple levels of protection components can safely absorb large voltage
spikes and provide highly effective RF filtering — the most comprehensive
protection available anywhere!
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Extreme Voltage Shutdown guards against catastrophically wrong voltages
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Power Status LED’s indicate which outlet groups have power
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Mains Wiring indicators monitor wiring integrity, show Normal and five kinds of
faults (not applicable to PS-PROE)
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Remote operation allows turn-on and turn-off at a distance simply by connect-
ing a momentary or maintained-contact switch (and LED if desired)
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Multiple units may be linked to handle higher currents and/or more than three
delay groups
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Three unswitched outlets (one front, two rear)
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Ten foot 12 AWG heavy duty power cord Export series ten foot 1.5 mm x 2 line
cord with Schuko plug
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Three year limited warranty
PS-PRO 20-AMP POWER CONDITIONER/SEQUENCER
PS-PRO 20-AMP POWER CONDITIONER/SEQUENCER
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Effects of Lightning
Lightning is a natural phenomenon of overwhelming force that represents the
most difficult circumstance faced by a power protection product. The degree of
protection a PS-PRO can offer depends on the intensity of the strike. If lightning
strikes a distant power line and causes a relatively small disturbance to reach your
location, the spike suppressors in the PS-PRO will absorb the excess voltage
invisibly and harmlessly. However, if lightning strikes the actual building where
the PS-PRO is installed (or somewhere very nearby), some damage may be
unavoidable due to the extremely high voltage and current present. If this does occur,
most likely damage will be limited to the PS-PRO itself and will affect only certain
spike suppression components (called varistors or MOV’s.) In this “suicide” mode,
the PS-PRO may sustain minor damage but generally will protect all
equipment plugged into it from much more serious and costly damage as
long as that equipment is properly grounded. Proper grounding requires the use of
three-prong AC cords, and that the building’s outlets are actually grounded to earth
as specified by the National Electrical Code. This is not necessarily applicable to the
PS-PROE as the IEC does not recognize the same electrical grounding standard.
Any PS-PRO known to have taken a direct lightning hit should be checked by a
qualified technician or the Furman factory to determine whether the MOV’s need
replacement. (If the PS-PRO’s PROTECTION OK indicator is not lit, there is
definitely some damage. Some spike suppression capability may still be available by
MOV Bank #2, but there is no guarantee of this.)
For optimum protection, you should not rely exclusively on the PS-PRO to
protect against a direct lightning hit. The first line of defense against lightning should
be a lightning arrestor installed on your building’s electrical service entrance. If your
building does not have one, contact your local power company or an electrical
contractor to have one installed.
