Answer / s bagchi

Step1: convert the kva or kw load into amps by dividing
with the respective voltage & pf in case of kw.
Step2: refer a cable catalogue & derate the current
considering temperature rating factor & group rating factor.
Step3: select a cable size considering the derated current.

at first you need to calculate the min cable size in case
of ht cables considering short time current & the fault
clearing time of the upstream breaker.

Answer / harshad

First calculate the current.
Eqn for 3phase: Current= Connected load in watt/sqr root of 3*415*pf

Eqn for 1phase: Current=Connected load in watt/230
Select the cable size from the chart with respect to the current.
pf(power factor) is 0.8 or 0.9

Why the ceiling fan rotate in anticlock wise direction whereas tables fan rotates at clock wise direction?

3 Answers  

---

how to find the resistance and gap volatage of the diode??

0 Answers  

---

i have a roll dia aprox.43 inches and gear box ratio is 14.3.so my question is how was decide the kw rating of motor.

1 Answers  

---

PLEASE SEND ME NTPC RELATED INFORMATION LIKE WHICH TOPICS HAV MORE SCOPE,BOOKS TO READ,CUT OFF...PLEASE.mail at thiru.1203@gmail.com

0 Answers  

---

Instrument connected to a single phase supply

0 Answers   Alstom,

---

Is MV canble armour can be earthed at both ends?

2 Answers  

---

What is the purpose of stand by earth fault protection for transformer ?

0 Answers  

---

Whats parameters which we keep in mind when grounded any electrical machine.

1 Answers   Essar,

---

how much current carry a 3-1/2 core of 100mm size cable.explain it with solution

2 Answers   ACS,

---

differentiate between c curve and d curve MCBS?

1 Answers  

---

why the arc welding machines require parallel earthing systems? ie why each machines are connected to earth pit by separate wires during earthing? wats it adavantages?

0 Answers  

---

all interview questions with answers of ntpc (2000-2009

0 Answers   Hetero, NTPC,

---