Elgar CW 801P-V Instrucciones de operaciones descargar pdf (Pagina 20)

Elgar CW-M Series

3.2 Wire Gauge Selection

The following guidelines assist in determining the optimum cable specification for

your power applications. These guidelines are equally applicable to both DC and low

frequency AC (up to 450 Hz) power cabling. 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 Elgar 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, the operating temperature needs to be considered. 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, which are designed for the

internal wiring of homes and buildings. Although these codes accommodate the safety

factors of wiring loss, heat, breakdown insulation, aging, etc., they consider that up to

5% voltage drop is acceptable. Such a loss directly detracts from the quality

performance specifications of this Elgar 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 that may be up to ten times the average values. An underrated

wire gauge adds losses that alter the inrush characteristics of the application and thus

the expected performance.

Table 3–1 identifies popular ratings for DC and AC power source cable wire gauges.

Column 1

Size (AWG)

Column 2

Amperes (Max)

Column 3

Ohms/100 ft (1 way)

Column 4

IR Drop/100 ft (Col 2 x Col 3)

14 15 0.257 3.85

12 20 0.162 3.24

10 30 0.102 3.06

8 40 0.064 2.56

6 55 0.043 2.36

4 70 0.025 1.75

2 95 0.015 1.42

1/0 125 0.010 1.25

3/0 165 0.006 1.04

Table 3–1 Recommended Wire Gauge Selection Guide

1 2 ... 15 16 17 18 19 20 21 22 23 24 25 ... 47 48

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Elgar CW 801P-V Instrucciones de operaciones Pagina 20

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