Appendix
AP1-6
1.2 How to calculate voltage drop in power cable
The unit is designed to work from specified power supply voltage +/-10 %. The
resistance at power supply connector and terminal can not be neglected in the
equipment. The power cable must be selected properly so that voltage drop is 3 to 5 %.
The maximum current in the power cable must be used for the calculation. In the
following examples, how to select the cable gauge is explained.
* Voltage drop in cable e=(K x I x r x L) / 1000
* Cable length L=(1000 x e ) / (K x I x r)
K=coefficient (single phase and DC: 2 three phases : / 3 )
I=current (A)
r=resistance : ohm/km
L=cable length (m)
Example)
* FM-8500
I=Tx current : 7 A e=0.72 V Cable drop : 3 %
r=DPYC-5.5sq : 3.36 ohm/km K=2
L=(1000 x 0.72) / (2 x 7 x 3.36)
=15.3 m
* Battery cable
I=Current : 50 A e=1.2 V Cable drop : 5 %
r=DPYC-38sq : 0.483 ohm/km K=2
L=(1000 x 1.2) / (2 x 50 x 0.483)
=24.8 m
* PR-850A AC cable (AC 220 V single phase line)
I=Current : 7 A e=11 V Cable drop : 5 %
r=DPYC-8 sq : 2.33 ohm/km K=2
L=(1000 x 11) / (2 x 7 x 2.33)
=337 m
To Next Page
Loading...
