Hi Sparks , i wonder if you could help me with what is probably an easy calculation for you . Can you tell me the maths for finding Zs if i have 10m of copper cable ( 1.5 / 1.00 mm )pvc twin/e if my Ze is 0.6 ohms. I have had a day of number crunching and my brain has melted .Please help as even the easy stuff now seems difficult .Cheers mate Jeff
Hi Jeff
sorry for late reply but been offline for a while;
Zs (system) = Ze(external loop L+E) plus R1+R2 (internal loop from con.unit L out to far end of circuit plus E conductor back to con. unit)
eg Ze + R1+R2= Zs.
you don't need to correct readings for temp. as in order to take resistance readings the circuit will be off load & at ambient room temp. which will be very close to tabulated readings in charts.
as a guide without looking tables up if 1.5 mm2 is say 0.12 Ohms then 1.0 should be 1/2 more ie 0.18 Ohms
giving Zs of 0.6+0.12+0.18= 0.9 Ohms
[quote="Jeffmo"]Hi Sparks , i wonder if you could help me with what is probably an easy calculation for you . Can you tell me the maths for finding Zs if i have 10m of copper cable ( 1.5 / 1.00 mm )pvc twin/e if my Ze is 0.6 ohms. I have had a day of number crunching and my brain has melted .Please help as even the easy stuff now seems difficult .Cheers mate Jeff[/quote]
JEFFMO
DISREGARDE PREVIOUS MESSAGE
TRY THIS
ZS = ZE+ R1 + R2
ZE = O.6 OMHS
R1 = 12.1MILLIOMH PER METRE
R2 = 18.1 MILLIOMH PER METRE
TOTAL R1 + R2 = LENGTH OF RUN X 30.2 X MULTIPLIER OF 1.2 / 1000
( MULTIPLIER OF 1.2 IS CORRECTION FACTOR FOR CONDUCTOR
OPERATING TEMPERATURE AT 20 DEGREES C )
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