Dear all,
Can anybody tell me that how to choose CT for a specific
load? I have a 200kw induction motor, which ratio CT should
be installed? Is there a formula or calculation that
determines the CT ratio for a load?
Regards.
Answers were Sorted based on User's Feedback
Answer / guest
I dont know of any formula to answer your question, but I
follow a trial method which worked out well for ME.First
know your full load current and the expected running
amperes which would be below your full load amperes.Now
choose your ampere meter which will show your running /full
load amperes at about 75% of the chosen amp meter scale.Now
you can select your CT .
In this case a 200 KW motor full load current is about 370
amps and for 75% scale reading would be 500 amps.So your CT
rating would be 500/5 and the amp meter also of the same
rating.
Is This Answer Correct ? | 6 Yes | 1 No |
Answer / k.prakashchandra
Another method.Divide KW by 0.75 (lowest pf expected) to get
KVA. Calculate current which is about 380 A at 400 V line
voltage.You can choose a CT 0f either 400 or 500 A as
primary current.The secondary current of CT is decided by
meter and relays.This is generally either 1 or 5 A .
Is This Answer Correct ? | 1 Yes | 1 No |
A 500 V shunt motor runs at its normal speed of 250rpm when the armature current is 200A. The resistance of the armature is 0.12 Ω. Calculate the speed when a resistance is inserted in the field reducing the shunt field to 80% of normal value and the armature current is 100A.
Upto what extent, the lagging power factor can be improved with the help of capacitors?
hw the cable size can be calculated when we have watss, volts, pf, i need the forula
How will you define capacitance?
what effect will 10 milliampere current cause to human body
the need of star to delta anddelta to star
iam preparing for rrb section engineer post in electrical branch.suggest the right textbook for my reference.fromwhere i will get the previous q.papers?
when we change tha taps from 1-16 in 100mva tr whether a constant voltage avaliable till it reaches tap 16 or voltage change as per taps change
in house wiring when two wires are same colour coding and there is no any connection one end how to find which wire is earthing wire
What are the usege & different between UPS & batteries with charging system in in Substation?( UPS 120V AC & battery charger is 120v DC)
please let me know , we have installed two separate motor for fire fighting system 1) 60 hp and 2) 15 hp the load is 74 AMPS and 20 AMPS then tell me the main power cable in Aluminum will be what thickness , the length is 225 mt from the main utility to fire pump house
What is the value of 3 phase voltage?