Answer Posted / praveen kandwal
A transformer consists of an metal core of laminated sheets about 0,35mm thick insulated from each other to reduce eddy current losses. The vertical parts are called the limbs and the horizontal parts are called the yokes. The two coils are wound on the limbs. One coil is called the primary coil and the other is called the secondary coil.
The metal core is made from a ferromagnetic metal selected because of its magnetic properties
An alternating voltage applied to the primary coil results in an alternating current which produces an alternating magnetic flux in the metal core. The current /flux level is just sufficient to induce an e.m.f that is practically equal and opposite to the applied voltage. The mean path of the alternating flux . Assuming all of the flux passes through the primary and the secondary winding,it induces the same e.m.f. in each turn of both coils. Hence if N1 and N2 are the number of turns in the primary and secondary coils respectively .
When the secondary winding is in open circuit its terminal voltage is the same as the induced e.m.f . The primary current is such that the induced e.m.f is equal and opposite to the applied alternating voltage.
When a load is connected to the secondary winding a current flows. This secondary current induces a magnetic flux which tends to reduce the current flow (Lenz's Law). The induced flux tends to reduce the magnetic flux and the resulting back back e.m.f.in the primary windigs This changes the difference between the applied voltage and the back e.m.f.in the primary windings from (say 0,05% to 1%). As a result the primary current increases, by say 20 times the no-load current. The demagnetising ampere turns of the secondary winding are thus neutralised by the increase in the primary ampere turns.. As the initial no-load primary ampere-turns are very small it can be stated that
Full load Ampere-Turns on (Primary) = Full load Ampere-Turns on (Secondary)
I1.N1 = I2.N2 ..therefore I1/I2= N2 /N1 = V2 /V1
In practice the above are all approximate
| Is This Answer Correct ? | 2 Yes | 7 No |
Post New Answer View All Answers
hi, i have 3x200KVA and 2 x 80KVA UPS with battery bank of 150AH 68Nos. and 100AH 204Nos., i need to install AC either ductable or PAC type, so can you help me to calculate heat load and capacity of the AC to install.
In single phase ac ups supply when current is measured with tong tester neutral current is found more than phase current.What is the reason?
How is magnetic leakage reduced?
slipring induction motor starting time Lrs operating why lrs starting time lrs outer body didn't get shock
What are protections for dty type transformers
An 8 pole, 50 Hz, 3-phase IM is loaded to a poing where pull out torque will occur. The rotor resistance per phase is 0.3 ohm and motor stalls at 650 rpm. The rotor reactance at stand still is A 2 ohm B 1.25 ohm C 3.15 ohm D 2.25 ohm
why don't we use the generator as a motor? and what will happen?
Why the standard of ambient teperature mentioned as 40 degree celcius in machines.
what is doid
What willbe change in programming when we use 5/3 solenoid inplace of 5/2 in operating of a cylinder?
Why Water motor is not taking a load or pressure while everything is correct. (Note: Motor running properly)
what is the difference between an alternator and a synchronous motor
What is the polarization index value ? (Pi value)and simple definition of polarization index ?
what is the meaning of 5% droop or 7% droop in AVR?
im working in one private compeny in gujarat. i was complet diploma electric in 2010 from gujarat technical board. now i want electric supervisor licence in gujarat but i dont't know when i apply? plz give me address of the licence dippartment office in gujarat. gandhinagar
