We have 800KW motor operating at 6600Volt,50 Hz
supply.During 1st startup it tripped on overcurrent
trip.It's FLA is 88 Amps.The K factor of Thermal overloaaad
was set on .94 initially.then we set at 0.97 and then it
started fine.i dont understand why it tripped first?What
are the protections which comes in picture during starting ?

Answer Posted / parveen garg

I DO NOT KNOW ABOUT 6.6KV MOTORS & ALSO ABOUT K FACTOR.BUT
ACCORDING TO UR QUESTION IT LOOKS THAT MOTOR DRAW MORE
INSTANTANOUS CURRENT THAN ASSUMED BY THE CALCULATION & AT
THIS STARTING CURRENT OLR TRIPPED,WHEN U INCREASE THE
SETTING OF OLR.IT DO NOT TRIP.
FOR THE PROTECTION POINT OF VIEW ONE EXTRA CONTACTOR MAY BE
PROVIDE IN PARALLEL TO THE OPERATING CONACTOR WITH TIMER
WHICH WILL MADE OFF THE CONATCTOR(PROVIDED NEWLY)&ALSO THIS
CONTANCTOR WILL DRAW POWER FROM MAIN BUSBAR WITH EXTRA OLR .

Is This Answer Correct ?    0 Yes 5 No



Post New Answer       View All Answers


Please Help Members By Posting Answers For Below Questions

What are the advantages of vscf wind electrical system?

636


where lt & ht capacitor used

1759


What do you mean by ratio correction factor of instrument transformer?

698


1)What is a Triode? What are its uses? 2) What is a Triac? 3) What is a Thyristor?

2065


How select ELCB for 32amp. socket having quantity 12Nos. We have to do this wiring in PLANT. Please Also explain the incoming cable specification.

1485






wat is the first thing dat is needed, 2 lay a cable in some area??

1413


What is Traction? 1KVA Alternator, How much urrent taken?

1600


HOW TO CALCULATE THE REGULATION OF 100 AND 25 KVA TRANSFORMER

1449


what is a pilot wiring and whys that called a pilot wiers

1352


electrical ques

1698


Describe the control mechanism of missile launcher???

1516


Can 4pole (3 phase+neautral )RCCB proper functioning in only 3 phase load (no neautral, no Earth) ?

1703


Determine the BTU size of an aircon for 20 sq metre room

1448


What will happen if we introduce negative feedback to a control system that uses a positive feedback?

676


What the difference between three phase contactor (coil 110vac) & three phase SSR (control voltage 110Vac)? May I use contactor in place of SSR?

1648