How does current transformer works?

Answer 1

A transformer is a device that transfers electrical energy from one circuit to another by magnetic coupling without requiring relative motion between its parts. It usually comprises two or more coupled windings, and, in most cases, a core to concentrate magnetic flux.

An alternating voltage applied to one winding creates a time-varying magnetic flux in the core, which induces a voltage in the other windings. Varying the relative number of turns between primary and secondary windings determines the ratio of the input and output voltages, thus transforming the voltage by stepping it up or down between circuits.

Answer 2

How A Current Transformer Works

Answer 3

A single wire carrying current generates a magnetic field. You can visualize this by making a loose fist with your right hand, and sticking your thumb out. The thumb indicates the direction the current is flowing in the single wire, and your fingers represent the magnetic lines of flux circling aroung the wire (current). This is called the right-hand-rule.

For AC current, simply rotate your wrist so your thumb points one way down the wire, then the opposite direction.

OK, so we have a magnetic field. The current transformer wraps around the wire (you pass the wire through the hole in the transformer) and the magnetic core (a toroid / donut shaped metal core) matches up with those magnetic lines of flux, and concentrates them. Many turns of small-gauge wire are wrapped around the core, and using the same right-hand-rule current will be generated in the small-gauge wire.

By knowing the number of turns around the core, and getting a core material that has the ability to concentrate magnetic lines of flux very well, you can accurately know how much current is flowing in the single wire. You measure the current in the transformer wire and use a constant multiplier for that specific current transformer.

One advantage of current transformers is that you can measure current without ever making direct contact with the single wire, because it might be at a very high voltage and dangerous.

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Answer 4

To tell The working in Simple terms Let me start it here:
Actually a current carrying coil Wound around a Core (Designed specially To avoid Losses) Creats a magnetic flux in simpler terms acts as a magnet Then another Coil (Wound around, Within the nearest range of the previously wound current carrying Coil ,on the same core) this induces a current in the latter coil which is connected to the load (Like a bulb)
Now to control the voltage of the secondary coil (The transformers Main Job) The ratio Of the primary and secondary coils are adjusted For (Eg. To step Down (To bring the voltage down , {in electrical terms.} )A 220 v ac to 12 v ac :
A primary coil of 220 (or 220*a to meet the wattage requirements) Windings are made on a core then a heat shrink is applied on the winding so as to separate the two windings to reduce losses then the second winding of 12 wounds (or 12*a to meet the wattage requirements) {a must be the same in the two windings} That's it!!! and now to put it into work the current is applied in the first transformer then the load connected to the secondary coil then the current in the first or primary coil induces a current in the second or secondary coil thus A12 v ac Current is produced) Based on usages the ratio is changed to meet the needs and also multiplied to meet the wattage requirments.
The nature of the current produced is dependent on the Primary current supply (i.e if primary current is ac as those on mains then the secondary Current is also the same (A.C) if the pri. curr. is D.C as those on Batteries then sec. curr. also D.C) And Remember the voltage is dependent on ratio while wattage on (a) multiplication of the same.
To create a simple transformer try this out ya........... :
Take an radio antenna wind 12* Say... 10 = 120 windings with a laminated copper wire (get it from a motor winding shop. ) then aplly heat shrink to separate the windings then wind another 6* Same... 10 = 60 windings (with the same type laminated copper wire ) Now tis ready yar............!!!
Take a multimeter and check it out !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
Bye...
Regards
Raghav
(Expecting comments!!!!!!!!!!!!!! :) )

Answer 5

electrical current generation requires 2 things. magnetic field and relative motion. normal generators get the relative motion from some sort of outside source (generally steam driven turbines) but a transformer is static. it gets its relative motion from the AC current moving through a coil.

you basically have 2 coils parallel to each other normally with a coupled core. as current goes through one coil it creates a kind of rotating magnetic field which meets both criteria of electrical generation. this is what generates the current in the secondary winding. the ratio of the number of turns from the primary winding to the number of turns in the secondary (called turns ratio) determines of the voltage is stepped up or stepped down. note that all that actually changes from one end to the other is the voltage. current and frequency should stay the same (well, since voltage changes so does the power technically)

DC currents cannot use transformers to change the voltage. DC does not have the sin-wave current that AC has which creates the relative motion required for electrical generation

Answer 6

Actually, the voltage tfr(transformer) and current tfr work on the same principle ....hope u know it.....all that is mentioned above....but the only difference is that, every tfr has its 'turns ratio'....
turns ratio=v1/v2=T1/T2=I2 / I1
where, v1 &v2 ,I1& i2, T1 & T2 are the primary & secondary voltages,currents and no. of turns respectively....
so if the secondary voltage,V2 varies w.r.t. the primary voltage as per the tuns ratio then current varies inveresly.....i hope its clear......now the same tfr can be used to stepdown or stepup current as the voltage tfr except that an ammeter is used in series with the secondary coil to measure the current instead of the voltmeter being connected in parallel with the secondary coil to measure voltage.....current is measured instead of voltage.....i hope its clear to you.......take care byeeeeee

Answer 7

I agree completely with tlbs101. His answer is perfectly accurate and covers the topic in more detail than most askers would expect. The other answers I looked at seem to not have any idea what a CT is or why people need them.

Answer 8

it works on principle of mutual inductance
used to increase or decrease alternating current