Discussion in 'Homework Help' started by peeka, Aug 7, 2009.

Apr 25, 2009
21
0
the following is a delta connected load,connect to a 3phase 240 volt 60 supply

a-b coil Z = 12 ohm pf = .7
b-c coil z = 20 ohm pf = .8
c-a coil z = 24 ohm pf = .7

now ive found the current per phase by Z X pf = A

i just have no idea ....well i forget how to add them all together to give me the total....

2. JoeJester AAC Fanatic!

Apr 26, 2005
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what did you figure for the power in each phase?

I don't think you found the current per phase with that formula.

Apr 25, 2009
21
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i got a few answers for the power of each phase,
ab - 2040
bc - 3840
ca - 4032

4. JoeJester AAC Fanatic!

Apr 26, 2005
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1,227
• write the formula you used
• write the numbers you used
That way we can diagnose the source of your error.

Only do the ab portion, as bc and ca are just replicates of ab.

Apr 25, 2009
21
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well all i did was workout the line voltage which is given,

delta 240 VL
line current for a-b is 34
phase current for a-b is 20

etc...same thing for the rest

then i just did P = root 3 X VL X IL
then i get no where coz they dont add up lol im thinking i have to add the phase angles via pythagorus...could u jsut work it out coz i need it asap my big exam is in 1 day

6. JoeJester AAC Fanatic!

Apr 26, 2005
3,403
1,227
P = (E^2 / Z) * pf

Try substituting the numbers into that formula then add the resultant powers.