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
2141 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

what is 3 phase motors

1 Answers AXA,

why need of ac exietation in alternater.

2 Answers

Is there any design in the world a 220 KV transformer without breather …??????

2 Answers

What is the formula to find out the kvar required to improve the powerfactor from .85 to .99 at 1500kw, 415v.

4 Answers Trident,

losses in transmission lines ?

0 Answers

What is the difference bet ween EDO Type & MDO type ACBs, and what is the advantage EDO Type over than MDO type ACBs.

2 Answers Siemens,

ow can i get certificate of competency as electrical supervisor and my diploma in electrical engineering from jalgaon.

0 Answers ONGC,

is there any concept of armature reaction in Induction motor?

4 Answers

how many power plants in andhra pradesh,how many types and there capacity

2 Answers

I have 12MW gas engine based power plant its running parallel with grid. my problem is When cpp run in island mode(without geb) that time geb transformer power factor is 0.2 lagging. When cpp run with parallel that time power factor is 0.94 lagging So how can i maintain power factor ofgeb transformer in island mode 0.9 lagging?

1 Answers SPCL,

In what situations relays are used in Circuit breaker? In Above what rating of Circuit breaker the relays are used? Why relays are not used for CB like MCB?

0 Answers Elektrotek,

what is the relative size of single and three phase?

0 Answers Student,

For more Electrical Engineering Interview Questions Click Here