Meyer Sound M3D - Manual (Page 9)

Meyer Sound Laboratories Inc M3D™ Line Array • 3
If the voltage decreases below the lower boundary of
either operating range (brownout), the supply uses
stored energy to continue functioning briefly.
The unit turns off only if the voltage does not increase
above the threshold before the storage circuits are
depleted. The time that the M3D or M3D-Sub continues to
operate during brownout depends on how low the
voltage drops and on the audio source level during this
period.
If the voltage fluctuates within either operating range,
automatic tap selection stabilizes the internal operating
voltage. This tap selection is instantaneous, and there
are no audible artifacts.
If the voltage increases above the upper boundary of
either range, the power supply rapidly turns off,
preventing damage to the unit.
If the M3D or M3D-Sub shuts down due to either low or
high voltage, the power supply automatically turns on
after three seconds if the voltage has returned to either
normal operating range. If the M3D or M3D-Sub does not
turn back on after ten seconds, remove AC power and
refer to the previous Caution note.
C
URRENT
R
EQUIREMENTS
The M3D or M3D-Sub presents a dynamic load to the AC
mains, which causes the amount of current to fluctuate
between quiet and loud operating levels. Since different
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 maximum
RMS current in a period of at least ten 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 cable size and
gauge and the rating for slow-reacting thermal breakers.
The maximum burst RMS current is the maximum RMS
current in a period of approximately one second. It is
used to select the rating for most magnetic breakers. The
maximum instantaneous peak current during 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
V pk (drop)= I pk x R (cable total)
For best performance, the AC Cable voltage drop should
not exceed 10 Volts, or 10% at 115V and 5% at 230V. Use
Table 1 below as a guide when selecting cable gauge size
and circuit breaker ratings for your operating voltage.
The minimum electrical service amperage required by a
system of M3D or M3D-Subs is the sum of their maximum
continuous RMS current. We recommend allowing an
additional 30% above the minimum amperage to prevent
peak voltage drops at the service entry.
Power Connector Wiring Conventions
The M3D or M3D-Sub requires a grounded outlet. It is
very important that the system be properly grounded for
both safety and proper operation. Use the following
wiring diagram to create power cables and distribution
systems.
!
CAUTION: If the Active LED does not
illuminate or the system does not respond to
audio input after ten seconds, remove AC
power immediately.
Verify that the voltage is within the proper
range. If the problem persists please contact
Meyer Sound or an authorized service center.
NOTE: It is recommend that the supply be
operated in the rated voltage windows, at least
a few volts away from the turn on/off points so
that small AC voltage variations do not cause
the amplifier to cycle on and off.
Table 1. M3D and M3D-Sub Current Ratings
115 VAC 230 VAC 100 VAC
Max continuous RMS 18A 9A 20A
Max. burst RMS 32A 16A 36A
Max. peak during burst 50A 25A 57A
Idle current 1.2A 0.6A 1.3A
!
CAUTION: In the unlikely event that the
circuit breakers trip (the white center buttons
pop out), disconnect the AC power cable. Do
not reset the breakers with the AC
connected. Contact Meyer Sound for repair
information.