We have drive feeding an output contactor for a 5000 hp motor @ 5kV applicatio

We have drive feeding an output contactor for a 5000 hp
motor @ 5kV application.

The motor FLA is 629amps x 1.25% service factor = 786.25
amps

The cable that we current have in place between the drive
and the output contactor is 350kcmil- MV-105 (parallel
cables). Per the NEC table 310.60 (C) (69). This show the
cable ampacity is at 615 amps per cable for a rating of
1230 amps.

We have derated the cable for the cable tray and the
multiple cables application and our calculations show that
after the correction factor factor we are at 922amps.
1230 amps x .75% correction factor factor = 922.5 amps.

The customer is driving us to then use another safety
factor of .25% off of the already derated cable. Can you
please provide a longhand calculation for your solution on
this application?

Question Posted / dbm

0 Answers
2114 Views
Siemens, I also Faced
E-Mail Answers

No Answer is Posted For this Question
Be the First to Post Answer

Post New Answer

More Electrical Engineering Interview Questions

line tester lamp working in which voltage?

3 Answers

Swg formulae

0 Answers Bokaro Steel,

How star and delta connections inherently eliminate triplend harmonics?

1 Answers Blue Star,

why in large rating C.T.s equipotential wires are used?

2 Answers Essar,

When generator connected, the circuit ELCB exploded. What is the reson?

3 Answers

Why tripping not occur when the transmission breaks? Doesn't we provide earthfault protection for it?

1 Answers

what should be the minimum rating for using HT Motors?

1 Answers BSL,

what is the use of neutral displacement relay

1 Answers OCL,

why some time Railway Fan not Rotate,But after a small rotation by human then it rotate normally? Why?

4 Answers

Dear, How much ph is maintained of water electrolite used in lrs for slipring induction motor ?

1 Answers

physical identification of HT & LT panel

0 Answers Schneider,

hello! can anyone explain to me how a 3 speeds table fan work? what are the factors that are controlling the speed of a normal table fan? Is it by varying the voltage or changing the magnetic field? would appreciate your reply :) thx in advance.

2 Answers

For more Electrical Engineering Interview Questions Click Here