Voltage Drop Calculation on 50HZ Systems
Voltage Drop Calculation on 50HZ Systems
(OP)
The values in Table 9 of the NEC are based on 60HZ. Where can I find tables that are based on 50HZ?
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Voltage Drop Calculation on 50HZ Systems
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Voltage Drop Calculation on 50HZ SystemsVoltage Drop Calculation on 50HZ Systems(OP)
The values in Table 9 of the NEC are based on 60HZ. Where can I find tables that are based on 50HZ?
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RE: Voltage Drop Calculation on 50HZ Systems
RE: Voltage Drop Calculation on 50HZ Systems
RE: Voltage Drop Calculation on 50HZ Systems
RE: Voltage Drop Calculation on 50HZ Systems
RE: Voltage Drop Calculation on 50HZ Systems
Is voltage drop a function of frequency?
///IEEE Std 141-1993 "IEEE Recommended Practice for Electric Power Distribution for Industrial Plants" Page 98 includes:
actual voltage drop=Es + IR cosfi + IX sinfi - [Es**2 - (IX cosfi - IR sinfi)**2]**0.5
which has some members dependent on frequency, e.g. X=2 x pi x f, therefore the voltage drop is generally dependent on the frequency.\\\
Suggestion to Chas (Electrical) Sep 10, 2001 marked ///\\\:
The values in Table 9 of the NEC are based on 60HZ. Where can I find tables that are based on 50HZ?
///Please, could you clarify that Table 9.\\\
RE: Voltage Drop Calculation on 50HZ Systems
www.olexcables.com.au has a handbook which is downloadable in PDF format from their website.
www.au.pirelli.com/uk/cables also lists volt drop figures.
Australian Standard AS/NZS 3008.1 is the Australian authority, providing tables of the volt drop figures for different cable configurations.
RE: Voltage Drop Calculation on 50HZ Systems
Delta(V)= (R)*PF + 0.80(X)sin [arcos(PF)].
The above relation used by NEC is satisfactorily for values of PF greater than 85 %, the resistance value at 50 Hz do not change significantly and the reactance at 50 Hz is 20% lower than the one at 60 Hz.
The justification of the above statement could be supported as bellow.
RESISTANCE:
The ratio of cable AC resistance at 60 Hz divided by the resistance at 50 Hz could be estimated as follow.
R60/50=1+5*10^-6*kcmil+1.7*10^-8*kcmil^2.
For practical application the resistance at 60 and 50 Hz is the same for cable size up to 250 kcmil. Above 250 kcmil the resistance at 50 Hz is reduced gradually up to 2.5% for 1000 kcmil cable. This small variation is produced by the skin effect.
REACTANCE:
X(f)=2Pi (f) [0.1404 log(s/r) + 0.0153]kx10^-3 Ohms/1000 ft
Therefore the ratio of cable reactance at 60 Hz divided by the reactance at 50 Hz could be estimated as follow.
X60/50=60/50=1.20.
RE: Voltage Drop Calculation on 50HZ Systems
http://www.iec.ch
http://www.iec.ch/cgi-bin/procgi.pl/www/iecwww.p?wwwlang=E&wwwprog=cat-det.p&wartnum=022544
(transformer voltage drop calcs)
http://www.lmphotonics.com/download.htm
(try software)
etc. for more info
RE: Voltage Drop Calculation on 50HZ Systems