R
CABLE
DC resistance of the cable at a given length
R
SOURCE
DC resistance of the source
R
TOTAL
Combined DC resistance of the cable and DC source:
R
TOTAL
= R
SOURCE
+ R
CABLE
V = IR
Ohm's Law
V
OC
=V
SOURCE
+ V
LOAD
Kirchoff's Voltage Law
Example 1
This example uses the following given values:
Given
V
DROP
= 2V
Maximum voltage drop through input source and cable
V
MIN
= 40V
Minimum input voltage
I
MAX
= 8.6A
Maximum input current at 40V
V
OC
= 48V
Measured
V
LOAD
= 47.5V
Measured
R
TEST
= 10Ω
(300W)
DS4243, DS2246, DS4486, and DS4246 Installation and Service Guide
65
Recommended power line sizes