11
AC Power
When AC power is applied to the PSW-6, the
Intel-
ligent AC
supply automatically selects the cor-
rect operating voltage, allowing the PSW-6 to be
used internationally without manually setting volt-
age switches. The Intelligent AC supply performs
the following protective functions to compensate for
hostile conditions on the AC mains:
suppresses high voltage transients up to sev-
eral kilovolts
filters common mode and deference mode
radio frequencies (EMI)
sustains operation during low voltage periods
provides soft-start power-up, which eliminates
high inrush current
The PSW-6 can withstand continuous voltages up to
275 V and allows any combination of voltage to
GND (i.e. Neutral-Hot-GND, Hot-Hot-GND). Con-
tinuous voltages higher than 275 V may damage the
unit.
The PSW-6 uses a NEMA L6-20P or IEC 309 male power
inlet and satisfies UL, CSA, and EC safety standards.
Voltage Requirements
The PSW-6 operates safely and without audio dis-
continuity if the AC voltage stays within either of two
operating windows: 85134 V or 165264 V, at 50 or
60 Hz. After applying AC power, the proper operat-
ing voltage is automatically selected, but the system
is muted. During the next three seconds, the pri-
mary fans turn on, the main power supply slowly
ramps on, the green
Active
LED on the user panel
illuminates, and the system is enabled to pass audio
signals.
TROUBLESHOOTING NOTE: If the Active LED does
not illuminate or the system does not respond to
audio input after ten seconds, remove AC power.
Electronics technicians with access to a test bench
can contact Meyer Sound to receive The Meyer
Sound Self-Powered Series MP-2 and MP-4 Field
Verification Procedure (part # 17.022.066.01). This
service document contains a series of tests to verify
that the power supply and amplifier are functioning
properly. Other users should contact Meyer Sound
or an authorized service center.
The PSW-6s power supply uses stored energy to
continue functioning for about 10 AC cycles if the
voltage decreases below 88V (a condition known as
brownout
). The precise length of time the unit func-
tions during brownout depends on the operating
level and how low the voltage drops. The unit turns
off if the voltage does not increase above 88V for 1
to 5 seconds. If the PSW-6 shuts down due to
brownout, the power supply automatically turns on
if the voltage returns to the normal operating range.
If the PSW-6 does not turn back on after ten sec-
onds, consult the Troubleshooting section
.
NOTE: We recommend that the supply be operated
at least a few volts away from the upper and lower
bounds of the operating range to avoid possible
shutdown.
Current Requirements
The PSW-6 presents a dynamic load to the AC
mains which causes the amount of current to fluctu-
ate between quiet and loud operating levels. Since
different types of cables and circuit breakers heat
up at varying rates, it is essential to understand the
types of current ratings and how they correspond to
circuit breaker and cable specifications.
The
maximum continuous RMS
current is the maxi-
mum RMS current in a period of at least 10 seconds.
It is used to calculate the temperature increase in
cables, which is used to select cables that conform to
electrical code standards. It is also used to select the
rating for slow-reacting thermal breakers.
The
maximum burst RMS
current is the maximum RMS
current in a period of approximately 1 second. It is used
to select the rating for most magnetic breakers.
The
maximum instantaneous peak current dur-
ing burst
is used to select the rating for fast-
reacting magnetic breakers and to calculate the
peak voltage drop in long AC cables according to
the formula
