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Zorluk: Çok zorInductors and Transformers

In an electronic power system, two ideal transformers are cascaded (connected in sequence).

Transformer 1 receives an input voltage of 1200 V AC1{}200\text{ V AC} on its primary coil, which has 3000 turns3{}000\text{ turns}. The secondary coil of Transformer 1 has 600 turns600\text{ turns}, and its output voltage is fed directly into the primary coil of Transformer 2.

Transformer 2 further steps down this voltage to supply exactly 48 V AC48\text{ V AC} to an electronic load.

If the secondary coil of Transformer 2 contains 50 turns50\text{ turns}, how many turns must the primary coil of Transformer 2 have?

Cevap: 250 turns

Cevap

250 turns
The correct answer is derived by sequentially applying the transformer turns ratio formula (Vp/Vs=Np/NsV_p/V_s = N_p/N_s) across the cascaded system. Transformer 1 operates with a 5:1 step-down ratio, reducing the 1200 V1{}200\text{ V} input to 240 V240\text{ V}. Transformer 2 receives this 240 V240\text{ V} and must further step it down to 48 V48\text{ V}, which also requires a 5:1 ratio. Multiplying the 5050 secondary turns by this ratio yields 250250 primary turns.

Adım Adım Çözüm

1
Calculate the secondary voltage of Transformer 1.
Vs1=240 V ACV_{s1} = 240\text{ V AC}
Using the turns ratio formula Vs1/Vp1=Ns1/Np1V_{s1} / V_{p1} = N_{s1} / N_{p1}, we find Vs1=1200×(600/3000)=1200×0.2=240 V ACV_{s1} = 1{}200 \times (600 / 3{}000) = 1{}200 \times 0.2 = 240\text{ V AC}.
2
Identify the primary voltage of Transformer 2.
Vp2=240 V ACV_{p2} = 240\text{ V AC}
Because the transformers are cascaded in series, the output voltage of Transformer 1 serves directly as the input voltage for Transformer 2.
3
Set up the turns ratio equation for Transformer 2.
Np2/50=240/48N_{p2} / 50 = 240 / 48
Applying the turns ratio formula Np2/Ns2=Vp2/Vs2N_{p2} / N_{s2} = V_{p2} / V_{s2} to the second transformer using its specific input and output voltages.
4
Solve for the primary turns of Transformer 2.
Np2=250 turnsN_{p2} = 250\text{ turns}
Np2=50×(240/48)=50×5=250 turnsN_{p2} = 50 \times (240 / 48) = 50 \times 5 = 250\text{ turns}.

Anahtar Kavram

Cascaded Transformer Turns Ratios
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