Answer Posted / yousef madhi

Suppose That the line voltage on DELTA connection
V(line)= V
and the line current I(line)= I

as we know in DELTA connection the phase voltage equal the line voltage and the phase current equal to the line current times 1/root(3)

then V(phase)=V(line) = V
and I(phase)=I(line)/root(3) = I/root(3)





In STAR connection if again the line voltage equal to V(line)= V , the phase voltage will equal to line voltage time 1/root(3)

V(phase)=V(line)/root(3) = V/root(3)

and as per Ohm's Law (V=I*Z) and in both connection (star & Delta) we have the same winding impedance, any change in Voltage will change the current in the same amount.

so the phase current for star connection will be equal to

I(phase-star)= I(phase-delta)/root(3)
=(I/root(3))/root(3)
= I/3

and as we know in star connection the line current equal to the phase current

I(line)=I(phase)= I/3





Conclusion:

the line current in star connection is reduced by 1/3 time the line current in delta connection

what is formula for zero phase sequence of nuetal earthing transformer of 6.6 kv

2344

---

what is saturation kit?which use above 15 kw motors panel side.

4249

---

IF % IMPEDANCE OF A TRANSFORMER IS INCREASED FROM 5.8% TO 8% HOW MUCH THE EFFICIENCY OF THE TRANSFORMER WILL COME DOWN?

2412

---

what does mean of RCT and STR in diffrential CT?

4287

---

ROC converges if pole and zero lies inside a) origin b) z=1 c) pole d) zero ? Explanation please? if ROC does not converges then?

2995

---

which protection function should measure RMS value of current&DFT value of current?

2135

---

What is the normal phase difference between the voltage and the no-load current in a transformer?

1314

---

What is phenomenon of electromagnetic induction and how it works?

1123

---

How would you calculate power loss in a resistor?

1127

---

differnce between single acting and double acting solenoid valves

1882

---

IN dc capacitive reactance is??

1451

---

what is allowable ac mixing in dc

2160

---

What is Primary And Secondary Injection Test of Relay and Other Electrical Devices. How IT is carried out.

3567

---

what is the transformer rush current?

2141

---

please send privious years question papers of jindal steel and power ltd.My e mail id is rajanikant.sngh@gmail.com

2144

---