Power cable
5-2
Chapter 5: Power and startup
98-146706-A
Example:
1 A and 50 mV. Source impedance: 50 mV/1 Amp = 50 mOhm.
Power cable recommendations
The ACU is delivered with a power connector (PCB plug-in connector, female plug,
Weidmuller, Part number 1930050000), which accepts wires up to AWG10/6 mm
2
.
• When installing the power cable, install positive and negative supply wires closely
together side by side to keep cable inductance low.
• Ensure that cable inductance for the selected cable at the desired length is less than
50 uH. Approximately 50 m maximum length.
Calculating the maximum power cable length
For 24 VDC operation, the total impedance must be max. 60 mOhm (R
max
), including the
source impedance in the ship installation (R
source
). The total impedance is the sum of the
following:
• Source impedance in the ship installation
• Impedance of the selected power cable
To calculate the maximum cable extension, do as follows:
1. Measure the source impedance in the ship installation as shown in Figure 5-1.
2. Find the resistance per meter (Rwire) for the cable type you are going to use.
4 mm
2
/AWG 11: 4.8 mOhm/m at 55°C
6 mm
2
/AWG 10: 3.8 mOhm/m at 55°C
Other cable types: see the data sheet for the cable.
The length is multiplied by 0.5 because there are two conductors in the cable.
If the SAILOR 6080 AC/DC Power Supply is used, use R
source
= 0 mOhm.
Figure 5-1: Measuring the ship source impedance
Note
If the total impedance is higher than the limits stated in
section , the terminal may become unstable and start to on/off
oscillate.
The total impedance is the sum of the source impedance of
the ship power supply plus the impedance of connected cables
including connectors and joints where cables are extended.
Maximum
length
0 5
Rmax Rsource
–
Rwire
=
SAILOR900Ka-IM-98-146706.book Page 2 Thursday, July 16, 2015 11:07 AM
