What is np and ns in transformer

The amount of voltage induced will be determined by: N*dΦ/dt (Faraday’s Law), where N is the number of coil turns. Also this induced voltage has the same frequency as the primary winding voltage.

Transformer Turn Numbers

Es = Secondary Voltage, Ep = Primary Voltage, … Np = Number of Primary turns.

There are three primary types of voltage transformers (VT): electromagnetic, capacitor, and optical.

ES/Ep = Ns/Np =K ——–(7)

If the secondary turns are more than the primary turns, the secondary voltage will be higher than the primary voltage and the turns ratio (K) is greater than 1. The transformer having voltage transformation ratio more than 1 is called step up transformer.

(1) Vp Vs = Np Ns and this is easy to remember as the voltage is proportional to the number of turns. … A transformers is called a “voltage step-up transformers” if the secondary voltage Vs is greater than the primary voltage Vp.

A Step Down Transformer is the device designed to reduce the voltage from primary to secondary. The transformation ratio of a transformer is equal to the square root of its primary to secondary inductance (L) ratio.

Induced emf per turn = rate of change of flux per turn. Therefore, average emf per turn = 4f Φ_m ………. (Volts). Now, we know, Form factor = RMS value / average value. Therefore, RMS value of emf per turn = Form factor X average emf per turn.

Volts per turn (V/turn) is the voltage dropped across each turn of a coil or the voltage induced into each turn of the secondary coil. Each transformer has a design value for the volts per turn. For example, if a transformer primary has 120 turns with a source of 120 V, it has 1 V/turn.

The turns ratio of a transformer is defined as the number of turns on its secondary divided by the number of turns on its primary. The voltage ratio of an ideal transformer is directly related to the turns ratio: … The turns ratio of a transformer therefore defines the transformer as step up or step-down.

V = 4.44 K_f K_C K_D f ΦT Volts.

V = Actual generated Voltage per phase. K_C = Coil Span Factor or Pitch Factor. K_D = Distribution Factor. K_f = Form Factor.

Vp=−NpΔΦΔt V p = − N p Δ Φ Δ t . This is known as the transformer equation, and it simply states that the ratio of the secondary to primary voltages in a transformer equals the ratio of the number of loops in their coils.

When the load on a system exceeds the amount of power that a single or existing number of generators can deliver, an additional generator is connected to the system to deliver required power. This method of adding an alternator in the existing system is called ‘parallel operation of alternators’.

In power engineering & electrical engineering, V curve is the graph showing the relation of armature current as a function of field current in synchronous machines keeping the load constant.

Putting the value of a in (2) gives the K_p which will go in (1) to get the winding distribution factor. Most of 3-phase motors have winding factor values between 0.85 and 0.95. The winding factor (along with some other factors like winding skew) can help to improve the Harmonic Contents in the generated EMF of machine.

Definition of damper winding

: a short-circuited squirrel-cage winding placed in the pole faces and around the pole shoes of synchronous machines, the currents induced in the winding by the periodic variations in synchronous speed having the effect of a damper. — called also amortisseur.

In this method, the lamps are connected across the phases such as A₁ is connected to B₂, B₁ is connected to C_2, and C₁ is connected to A₂. If all the three lamps get bright and dark together, this means that the phase sequence is correct.

But the alternator conductors are calculated for a definite current and the insulation at magnetic system are designed for a definite voltage independent of p.f. (Cos θ) of the load. For this reason apparent power measured in kVA is regarded as the rated power of the alternator.