a strange question

[SirKit Breaker]

Wow I am impressed........... A bit ( a big bit) out of my league though

Cheers..........Howard

 

[IQ Electrical]

one more ?

a circuit with a capacitor of capacitive reactance 5 ohms an induction of 8 ohms inductive reactance and a resistor of 4 ohms conected in series to a 230v 50hz supply what would the total impedance be
a 5 ohms
b 10 ohms
c 3 ohms
d 6 hms

is it 2 x pie x f x l

Z = square root of R^2 + X^2

X = Xl - Xc

X = 3

Z = square root of 16 + 9

Z = 5 Ohms

 

[IQ Electrical]

Where there is capacitive reactance and inductive reactance, the value of X is always the larger value minus the smaller which in this case is 8-5 = 3

 

[reedsinthewater]

1/2x3.142x50x25x10 to the power of minus six. The 'funny u' represents micro farads, hence to the power of minus six.

 

[reedsinthewater]

1/2x3.142x50x25x10 to the power of minus 6, the 'funny u' represents micro farads, hence to the power of minus six.

 

[lofty84]

an a.c load has an output power of 12 kw and an input of 15 kva. determine the reactive power

can anyone work this out it looks simple but i cant remember what to do again

 

[IQ Electrical]

KVAr^2 = KVA^2 - KW^2

Or use KVAr = sqare root of KVA^2 - KW^2

KVAr = sqare root of 225 - 144

= 9 KVAr

 

[lofty84]

you know your stuff mate, nice one

 

[IQ Electrical]

No problem, it keeps my AC theory fresh too!

 

[lofty84]

Heres a weird one

what are the copper losses in the primary winding of a step up tansformer, where the resistance of the winding is 0.3 ohm and the transformer is drawing 8 amps from the supply ?

any Ideas IQ ?