Chapter 2: Power Requirements; Ac Power Distribution - Meyer Sound 750-LFC Series Operating Instructions Manual

CHAPTER 2: POWER REQUIREMENTS

The 750-LFC design combines advanced loudspeaker
technology with equally advanced power capabilities.
Understanding power distribution, voltage and current
requirements, and electrical safety guidelines is critical to the
safe operation of the 750-LFC.

AC POWER DISTRIBUTION

All components in an audio system (self-powered
loudspeakers, mixing consoles, and processors) must be
properly connected to an AC power distribution system,
ensuring that AC line polarity is preserved and that all
grounding points are connected to a single node or common
point using the same cable gauge (or larger) as the neutral and
line cables.
CAUTION: Make sure the voltage received by the
!
750-LFC loudspeaker remains within its 90–264 V
AC operating range. In addition, the ground line must
always be used for safety reasons and the
line-to-ground voltage should never exceed 250 V AC
(typically 120 V AC from line to ground).
CAUTION: Before applying AC power to any
!
Meyer Sound self-powered loudspeaker, make
sure that the voltage potential difference between the
neutral and earth-ground lines is less than 5 V AC when
using single-phase AC wiring.
NOTE: Improper grounding of connections
between loudspeakers and the rest of the audio
system may produce noise or hum, or cause
serious damage to the input and output stages of the
system's electronic components.
120 V AC, 3-Phase Wye System (Single Line)
Line-Neutral-Earth/Ground
Figure 8 illustrates a basic 120 V AC, 3-phase Wye distribution
system with the loudspeaker load distributed across all three
phases, each loudspeaker connected to a single line, and
common neutral and earth/ground lines. This system delivers
120 V AC to each loudspeaker.
Loudspeaker
(120 V AC)
Line 1 (120 V AC)
Line 2 (120 V AC)
Line 3 (120 V AC)
Neutral
Earth/Ground
Figure 8: 120 V AC, 3-Phase Wye System (Single Line to Loudspeakers)
120 V AC, 3-Phase Wye System (Two Lines)
Line-Line-Earth/Ground
Figure 9 illustrates a 120 V AC, 3-phase Wye distribution
system with each loudspeaker connected to two lines and a
common earth/ground line. This configuration is possible
because the 750-LFC loudspeaker tolerates elevated voltages
from the ground line and does not require a neutral line. This
system delivers 208 V AC to each loudspeaker.
Loudspeaker
(208 V AC)
Line 1 (120 V AC)
Line 2 (120 V AC)
Line 3 (120 V AC)
Neutral
Earth/Ground
Figure 9: 120 V AC, 3-Phase Wye System (Two Lines to Loudspeakers)
TIP: The 120 V AC, 3-phase Wye system with
two lines is recommended because it allows
loudspeakers to draw less current than with
single-line systems, thereby reducing voltage drop due
to cable resistance.
Loudspeaker Loudspeaker
(120 V AC) (120 V AC)
Loudspeaker Loudspeaker
(208 V AC) (208 V AC)
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