Sorensen SFA Series, Руководство по эксплуатации

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Installation Sorensen SFA Series
2.6
WIRE GAUGE SELECTION
The following guidelines assist in determining the optimum cable specification
for your power applications. The same engineering rules apply whether going
into or out of an electrical device. Thus, this guide applies equally to the input
cable and output cable for this Sorensen instrument and application loads.
Power cables must be able to safely carry maximum load current without
overheating or causing insulation destruction. It is important to everyday
performance to minimize IR (voltage drop) loss within the cable. These losses
have a direct effect on the quality of power delivered to and from instruments
and corresponding loads.
When specifying wire gauge, consider the operating temperature. Wire gauge
current capability and insulation performance drops with the increased
temperature developed within a cable bundle and with increased environmental
temperature. Thus, short cables with generously derated gauge and insulation
properties are recommended for power source applications.
Avoid using published commercial utility wiring codes. These codes are
designed for the internal wiring of homes and buildings and accommodate the
safety factors of wiring loss, heat, breakdown insulation, aging, etc. However,
these codes consider that up to 5% voltage drop is acceptable.
Such a loss directly detracts from the quality performance specifications of this
Sorensen instrument. Frequently, these codes do not consider bundles of wire
within a cable arrangement.
In high performance applications, as in motor start-up and associated inrush/
transient currents, additional consideration is required. The cable wire gauge
must consider peak voltages and currents, which may be up to ten times the
average values. An underrated wire gauge adds losses, which alter the inrush
characteristics of the application and thus the expected performance.
Table 2–5 identifies popular ratings for DC power source cable wire gauges.
2-6 M550292-01 Rev C