What is the flux of transformer?
The main flux is the flux found in the core at a point not under either the primary or secondary winding, and has been commonly considered as being the flux which causes the secondary induced voltage. …
Why is emf max when flux is zero?
As the coil turns and the plane of the coil becomes parallel to the field lines, the flux becomes zero. By Faraday’s law, the magnitude of the induced emf is equal to the rate of change of magnetic flux, so its maximum values occurs when the flux curve has its greatest slope.
How is back EMF created?
A motor has coils turning inside magnetic fields, and a coil turning inside a magnetic field induces an emf. This emf, known as the back emf, acts against the applied voltage that’s causing the motor to spin in the first place, and reduces the current flowing through the coils of the motor.
What is the maximum value of emf?
emf=2Bℓw2ωsinωt=(ℓw)Bωsinωt emf = 2 B ℓ w 2 ω sin ω t = ( ℓ w ) B ω sin . is the maximum (peak) emf. Note that the frequency of the oscillation is f = ω/2π, and the period is T = 1/f = 2π/ω. Figure 3 shows a graph of emf as a function of time, and it now seems reasonable that AC voltage is sinusoidal.
What is the flux when the current is maximum?
The electric flux of a surface is maximum when the area vector is parallel to the direction of the electric field. The electric flux is the total number of lines of force passing through a surface. Electric flux is proportional to the number of electric field lines going through a virtual surface.
How are the emfs of a transformer related?
Referring to Eq. 1, it is clear that the volts per turn is exactly the same for both the primary and secondary windings i.e. in any transformer. The secondary and primary induced emfs are related to each other by the ratio of the number of secondary and primary turns.
How is the magnetic flux of a transformer set up?
When an alternating (sinusoidal) voltage is applied to the primary winding of a transformer, an alternating (sinusoidal) flux is set up in the iron core which links both the windings (primary and secondary windings). As illustrated in Fig. 1, the magnetic flux increases from zero to its maximum value in one-fourth of a cycle
How to calculate the emf of a 10 kVA transformer?
Example 2: The emf per turn of a single phase 10 kVA, 2200/220V, 50 Hz transformer is 10V. Calculate (i) the number of primary and secondary turns, (ii) the net cross-sectional area of core for a maximum flux density of 1.5T.
What makes up the exciting current in a transformer?
The no-load primary current I 0, called the exciting current, is very small in comparison to the full-load primary current (2-5% of full load primary current). This current is made up of a relatively larger quadrature or magnetizing component I m and a comparatively small in-phase or energy component I e.