What are the difference between C-Curve and D-Curve for
MCB's.
Answer Posted / h.shastri
almost all answer is somewhat correct
the main thing is to selection of proper MCB which matches
with your equipments and instruments
for that i'd like to give you an case study...
let's Assume one Heating Control Action
suppose i am using a 1ph. heater of 1200 Watt (5.2 Amps)
now i am controlling heating action using an SSR or
relay/contactor
now if i will select SSR (relay/contactor)'s rating =6 amps
and i also impliment MCB of 6 Amps.b-curve
then in case of heater failer or implimenting different
rating's heater,
assume that circuit is taking some higher current say, 10
Amps in such my SSR(relay/contactor)will damage due to high
load current which is higher then their rating of 6 Amps
but MCB will not trip instently ( it trips after 5-10 min.
because load current is not more then 12 Amps)
in this case MCB will not protect your instruments.
now if i'll decrease MCB's rating it will starts tripping
on and on.....
if i'll select MCB more then 6 Amps again in this case MCB
will not trip
so that, if i m using b curve 6 Amps MCB then i must select
SSR(relay/contactor)'s rating more then 12 Amps say 15Amps.
then and then problem will be solve.
also if i will use MCB of C or D curve then Again i have to
choose instruments which has atleast 3-5 times higher
rating of MCB.
| Is This Answer Correct ? | 66 Yes | 12 No |
Post New Answer View All Answers
How many types of colling system it trformers?
Why MCCB is Getting tripped sometimes when there is no load in the Midnight ?
Why is negative feedback invariably preferred in closed loop system?
What is the effect of positive feedback on the stability of the systems?
what is difference between earthingpits,earthing grid & earthing mess?
Is there any rule to select the voltage of motor based on KW rating? What is the rating above which lt motor becomes the HT motor?.
How to check the Bushings of the transformer?
kindly send me 11KV MV motor differential protection procedure by primary injection method.
What is the basic principal, by which DC voltage level is increased more than the supplied AC voltage during conversion. As upto AC level it is contorrled by firing anlge but after maximum level how is it possible.Please clear picture. OR we have to supply the higher level AC?
Dear all: Recently we got a question about Interface between PMS and SAP-PM.once we got a update message from PMS.we should set the deletional flag for functional location in SAP system.Is there any FM or BAPI to use?There are only functional location create and change provided by SAP. Best regards!
I HAVE A 50A MCCB AS PER DESIGN LINE WIRE CONNECT UPWORD SIDE AND LOAD IS CONNECTED TO DOWNWARD SIDE TO THE MCCB.IF NOW ANY ONE CHANGE SUPPLY & LOAD(WISEVERSA) WHAT HAPPENS ? DOES MCCB OPERATION OR WORKING FUNCTION NORMAL IF YES THAN WHY THERE ARE MARKED LINE & LOAD ON MCCB.
In a large office how do we calculate required number of light fittings, assuming fittings are 4x18W or 2x36W fluorescent fitting ?
What is rotary phase converter?
what is the differencce inn series and cascade connection??
Explain in brief description about the operation of DG sets.