Samlex Europe PST-300S-12E Manual Del Propietário página 33

SECTION 8 |
8.4.3 Connection from Batteries to the DC Input Side – Sizing of Cables
and Fuses
!
CAUTION!
The input section of the inverter has large value capacitors connected across the
input terminals. As soon as the DC input connection loop (Battery (+) terminal "
External Fuse " Positive input terminal of EVO " Negative input terminal of the
EVO " Battery (–) terminal) is completed, these capacitors will start charging and
the unit will momentarily draw very heavy current to charge these capacitors that
will produce sparking on the last contact in the input loop even when the unit is in
powered down condition. Ensure that the fuse is inserted only after all the connec-
tions in the loop have been completed so that sparking is limited to the fuse area.
Flow of electric current in a conductor is opposed by the resistance of the conductor.
The resistance of the conductor is directly proportional to the length of the conductor
and inversely proportional to its cross-section (thickness). The resistance in the conductor
produces undesirable effects of voltage drop and heating. The size (thickness / cross-
section) of the conductors is designated by mnµ. Table 8.1 below gives Resistance in Ohm
( ) per 30 cm at 25°C / 77°f for the wire sizing recommended for use with this inverter.
Table 8.1 Wiring Resistance per Foot
WIRE SIZE,
Mmq
35 Mmq
50 Mmq
70 Mmq
95 Mmq
105˚C/221˚f. As current
permissible value of current (called "Ampacity") for each size of conductor based on
temperature rating of its insulation. The insulating material of the cables will also be
affected by the elevated operating temperature of the terminals to which these are con-
nected.
The DC input circuit is required to handle very large DC currents and hence, the size of the
cables and connectors should be selected to ensure minimum voltage drop between the
battery and the inverter. Thinner cables and loose connections will result in poor inverter
performance and will produce abnormal heating leading to risk of insulation melt down
and Normally, the thickness of the cable should be such that the voltage drop due to
the current & the resistance of the length of the cable should be less than 2% to 5%. Use
Installation
produces heat that affects insulation, there is a maximum
RESISTANCE IN OHM ( )
PER FOOT AT 25°C / 77°F
0.000159 per 30 cm
0.000096 per 30 cm
0.000077 per 30 cm
0.000050 per 30 cm
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