why the CT ratio secondary is always divided by 5 for eg(
75/5,80/5,50/5)

Answer Posted / iamdon

CT is used mainly for Instrumentation(Measurement and
protection system) purposes thats why it is also termed as
instrument transformer.The measuring and protecting devices
are not rated to sustain high currents.What a CT does is,
it lowers the current in secondary side so that measurement
as well protection can be done at a reduced level of
current.

The digit in CT ratio of secondary side is IS standard for
rated secondary current so that uniformity among manufactures
be established.
The various values of secondary currents are
1)in the range of 0-5 amp e.g, 1A,5A
2)in the order of mA(particularly 40mA)in case of digital
devices for measurements and protection.


Perhaps Shayam had ingnored this fact.It cann't be any
number.

Author:arbelectbit@yahoo.com

Is This Answer Correct ?    15 Yes 2 No



Post New Answer       View All Answers


Please Help Members By Posting Answers For Below Questions

Define resonant frequency?

719


Earth is a conductor or load?then ammeter connect to 3- phase supply,it shows the measurents or not?

1638


1.what is mean by 8/20 micro sec waveshape

1791


what happened when we supply a dc current in dc motor?? can it worked properly?

1460


There is any especial requirement for motor to drive through with VFD?

2176






when we gave dc supply to 220v dc motor its rpm is 1200. then we gave 180v. how many rpm of its motor. gave answer with calculation at my ID.... ravizak@ymail.com

1844


what is cathodic protaction?

1492


what is transient enclosure vltage , very fast transients, very fast transient over voltages

1642


what will happen if there is a voltage leakage or current leakage in an electrical train

1503


What Normal(Tangent) towers and Tension(Cut-point) Towers?

5217


what is the advantages og idmt relay over magnetic relay??

3720


I have a drawing of a wound rotor induction motor for a crane. This crane motor has 5 forward speeds & 5 reverse speed implemented of course with different amount of resistance for each speed setting selected. What has got me scratching around is the fact that 8 of the 10 speed selections switch in uneven (unbalanced) amounts of resistances on each of the 3 connections to the motor's rotor.Can this be possible? I would have assumed this would produce unbalanced rotor currents and therefore vibration in the motor. I would greatly appreciate anyone's comments on this. Many thanks, Confused.

1403


Why does the Solid state Rectifiers for 3-ph brake motors sometimes have 2 & sometimes 3 output terminals?

1605


How halogen & merquery lamp works.

1679


what is the terminal voltage of dc series generator running at rated speed at no load?

6401