COBHAM SAILOR 6120, Installation Manual

Page: 48 / 116

Chapter 3: Connect the system
36 Connect power
3.4.4.2 Calculate the maximum power cable length
Max. total impedance:
•
29 VDC
operation:
max. 2.7 ohm
including the source impedance of
the ship installation.
To calculate the maximum cable length, do as follows:
1. If you are using the SAILOR 6081 PSU go to step 2. If you are using
another DC power source or want to extend the included cable then
measure the source impedance as shown in
Measure the ship source
impedance on page 38.
2. Find the resistance per m for the cable type you are going to use.
Table 5 shows typical cable resistance - note that your cable type may
differ from this. Refer to the data sheet for the cable you are using.
3. Calculate the maximum cable length as follows:
0.5 x (max. total impedance
1
- measured source impedance)
Max. cable length =
cable impedance per meter
1.
Max. total impedance
:
29 VDC operation: max. 2.7 ohm including the source impedance of the
ship installation.
Important
The max. cable length is
200 m
if the cable is also carrying
the communication interface and not just power.