Answer / 7anoter4

You intend to run 3 cables of 3*50 mm^2 and 2 cables of
3*35 mm^2 type AYFY, I guess.
It depends on type and width of the cable trays. Let’s say
you want to use an open top and ventilated tray [ladder or
well perforated plate] and you want to carry the maximum
possible currents. Then, according to IEC 60364-5-52 Table
A.52-17 Note 2-you have to keep two cable diameters
clearance between cables and at least 0.3 time cable
overall diameter from the wall-both ends.
A 3*50+25 0.6/1 kV [according to IEC 60502-1] aluminum
conductor [compact], pvc insulated, steel tape armored and
pvc serving overall diameter 34 mm and for 3*35+16 overall
dia= 30 mm.
Here is the width calculation:
|0.3*34|O|2*34|O|2*34|O|2*34|o|2*30|o|0.3*30| where O =one
3*50+ cable diameter and o=one 3*35+ cable dia.
That means:
0.3*34+34+2*34+34+2*34+34+2*34+30+2*30+30+0.3*30=445.2
Then the tray width will be more than: 445.2 mm.
In 30 dgr.C air permissible current-carrying capacity will
be:
[See Table A.52-11 – Current-carrying capacity in amperes
system E aluminum]
[Or Tableau B.52-1 for aluminum col.7]
3*50 117 A
3*35 96 A
You may reduce the cable tray width but you have to reduce
the current in order to limit the conductor temperature to
70 dgr.C.

Answer / 7anoter4

For open top solid bottom cable tray and without any
clearance between cables the cable carrying capacity
has to be reduced to 73%. However the tray width will be
only:
0.3*34+34+34+34+30+30+0.3*30=181.2 mm
3*50+ 117*.73= 85.4 A ; 3*35+ 96*.73=70 A

Answer / 7anoter4

The cable tray is an assemble of tens or hundreds parts.
There are a big number of types and materials involved. You
may get a look in IEC 61537 or NEMA VE-1 or VE-2.

The simple way is to take the construction drawings and to
make a sketch of the cable tray run including the all
derivation on this drawing and then to send this to some
tray manufacturer as B-Line [for instance, you can find
many of them in web or Google].

How voltage regulation is calculated for over head transmission line? What do we mean by Conductor constant while calculating voltage regulation? how it is differ for for diffrent type of conductor say AAAC DOG & AAAC RACOON conductor?

3 Answers   ABB, AES,

---

What is the full form of PSD & CSD ?

6 Answers   NIFT, PNG Power, PSD,

---

What do you mean by deregulated power system structure? Which structure (regulated/deregulated) is used by modern power system?

1 Answers  

---

is it possible to minimize the copper loss?

2 Answers   Coal India, TATA,

---

Why P.F(power factor)relay should not be connected to the D.G(diesel generator) incomer side

1 Answers   ABB, Corsa,

---

---

what is the working of vfd drives.

2 Answers  

---

what is the design factor that affects the size of a motor ?

3 Answers   Reliance, SGI,

---

what is the relation between Sq mm of wire and its current carrying capacity?

5 Answers   Finolex,

---

Sir, I have applied for the of Assistant.engineer of NPDCL. please send me all AP TRANSCO AND JENCO solved papers of previous exams . I requested send me the papers to my id as soon as possible (rajanikanth_peddi@yahoo.co.in) (This is very urgent) Thank You,

0 Answers   APTransco,

---

Conventionally, capacitors are considered to generate reactive power and inductors to consume it,how??????

1 Answers  

---

What is Icu and Ics and what is difference b/w them. please tell me how to calculate a size of a copper bar for a system or a breaker... reply on... king.arish@gmail.com would be waiting for a logical answer.

0 Answers  

---

when we start the tube light, then it takes initially 1100 volt, after glow it takes 120 volt?(when we give 220 volt a.c.)

3 Answers  

---