Apogee APL-220, Руководство пользователя

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AWG# 86°F (30°C) 1 04°F (40°C)
1 4
1
2
1
0
8
1 5 A
20 A
25 A
35 A
1 2.3 A
1
6.4 A
20.5 A
28.7 A
6.9 A
8.7 A
1
4.5 A
20.3 A
Ambient Temperature
As you can readily see from Chart 2, the maximum permissible current rat-
ings decrease rapidly as the ambient temperature rises. Carefully consider
the ambient temperature in which the equipment will be used when deter-
mining appropriate wire gauge size.
1 2
1 22°F (50°C)
Chart 2
(4) Voltage Drop
Another important consideration in determining appropriate wire gauge is
the voltage drop that occurs across the cable’s resistance. This is a function
of the gauge and the length of the conductors, the current drawn by the load,
and the starting AC mains voltage. Generally, the permissible voltage drop
should not exceed 2.5% of the working voltage for audio loads. Although the
APL-220, -500, and -800 power supplies automatically compensate for volt-
age drops down to 90V AC in the
11
5V AC setting and
1
90V AC in the 230V
AC setting, it’s important to provide adequate power to the powered loud-
speaker by choosing appropriate cable sizes. A drop in voltage across the
power cable will cause the intelligent power supplies to draw more current
thereby causing the voltage to decrease even more. If the voltage drops
below 90V AC or
1
90V AC, damage may occur to the unit.
Chart 3 shows voltage drop as a percentage of the nominal working voltage
for typical lengths of cables at
1 20V AC and 240V AC. The shaded areas show
cable lengths and loads that result in 2.5% or less of voltage drop.
(NOTE: AWG stands for American Wire Gauge.)
Chart 2 provides the basic guidelines of The National Electric Code for four
common gauges of copper wire related to permissible load in amperes.
Chart 2 applies to three-conductor portable cordage of the types S, SO, SP,
SPT, SJ, and SJO, which are typically rated at a maximum operating tempera-
ture of
1 40°F (60° C). (NOTE: Operating temperature is the heat generat-
ed within the cable from the voltage drop added to the ambient tempera-
ture.) Chart 2 covers ambient temperatures of 86°F (30°C),
1
04°F (40°C),
&
1
22°F (50°C).
For safety reasons, the maximum ratings in the table below should never
be exceeded.