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CHAPTER 2: MDM-832 POWER REQUIREMENTS
CAUTION:
For 230 V AC, 3-phase Wye sys-
tems, never connect two lines along with the
neutral line to the AC Input of the MDM-832, as the
resulting voltage would be higher than the allowable
upper voltage range (240 V AC) and would damage
the unit.
MDM-832 VOLTAGE REQUIREMENTS
The MDM-832 operates as intended when receiving AC volt-
age within the following range:
100–240 V AC, 50–60 Hz.
■
If the voltage rises above 267 V, the power supplies of con-
nected loudspeakers could become damaged. The
MDM-832 allows any combination of voltage to ground
(neutral-line-ground or line-line-ground).
CAUTION:
The power source for the MDM-832
should always operate within the required volt-
age range, at least a few volts from the upper and
lower ranges. This ensures that AC voltage variations
from the service entry — or peak voltage drops due
to cable runs — will not cause the amplifiers of con-
nected loudspeakers to cycle on and off or cause
damage to loudspeaker power supplies.
MDM-832 CURRENT REQUIREMENTS
The current draw for the MDM-832 and its connected loud-
speakers is dynamic and fluctuates as loudspeaker operat-
ing levels change. Since different cables and circuit breakers
heat up at varying rates, it is important to understand the fol-
lowing types of current ratings and how they affect circuit
breaker and cable specifications.
■
Idle Current — The maximum rms current during idle
periods.
Maximum Long-Term Continuous Current — The
■
maximum rms current during a period of at least 10 sec-
onds. The maximum long-term continuous current is
used to calculate temperature increases for cables, to
ensure that cable sizes and gauges conform to electrical
code standards. The current rating is also used as a rat-
ing for slow-reacting thermal breakers, which are recom-
mended for loudspeaker power distribution. In addition,
the maximum long-term continuous current can be used
to calculate the AC looping capability for the distribution
module and loudspeakers.
Burst Current — The maximum rms current during a
■
period of around 1 second. The burst current is used as
a rating for magnetic breakers.
8
■
Ultimate Short-Term Peak Current — A rating for
fast-reacting magnetic breakers. It is also used for calcu-
lating the peak voltage drop in long AC cable runs
according to the following formula:
V pk (drop) = I pk x R (cable total)
For maximum load values for the MDM-832, see
Appendix C, "MDM-832 Specifications."
The minimum electrical service amperage required by the
MDM-832 is the sum of the maximum long-term continuous
current for all connected loudspeakers, up to the rating of the
breakers. When calculating the total current draw at the
MDM-832 AC Input, an additional 30 percent above the min-
imum amperage is recommended to prevent peak voltage
drops at the service entry.
NOTE:
For best performance, the AC cable
voltage drop should not exceed 10 percent of
the sum of the maximum long-term continuous cur-
rent for all connected loudspeakers. Make sure that
even with AC voltage drops that the AC voltage
always remains within the operating window.
POWERING ON THE MDM-832
When powering on the MDM-832 and switching on the
breakers, the AC voltage presence LEDs on the front panel
light up to indicate the presence of AC voltage at each cir-
cuit breaker.
CAUTION:
If the AC voltage presence LEDs do
not light up, or loudspeakers connected to the
MDM-832 do not output audio after 10 seconds,
switch the breakers to the OFF position and remove
AC power immediately, and verify that the voltage is
within the required range. If the problem persists,
contact Meyer Sound Technical Support.
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