A step down transformer is connected to 2400 volts line and 80 amperes of current is found to flow in output load. The ratio of the turns in primary and secondary coil is 20: 1. If transformer efficiency is 100%, then the current flowing in the primary coil will be

Question

A step down transformer is connected to 2400 volts line and 80 amperes of current is found to flow in output load. The ratio of the turns in primary and secondary coil is 20: 1. If transformer efficiency is 100%, then the current flowing in the primary coil will be (A) 1600 amp (B) 20 amp (C) 4 amp (D) 1.5 amp

Tardigrade Admin · Accepted Answer

(Ns/Np)=(Vs/Vp ⇒ (1)20=(Vs)2400 ⇒ Vs=120 V For 100 % efficiency V/s) is=Vp ip ⇒ 120 × 80=2400 ip ⇒ i p=4 A

Q. A step down transformer is connected to 2400 volts line and 80 amperes of current is found to flow in output load. The ratio of the turns in primary and secondary coil is 20 : 1. If transformer efficiency is 100%, then the current flowing in the primary coil will be

1600 amp

20 amp

4 amp

1.5 amp

$\frac{N _{s}}{N _{p}} = \frac{V _{s}}{V _{p} \Rightarrow \frac{1}{20} = \frac{V _{s}}{2400} \Rightarrow V _{s} = 120 V}$
For $100%$ efficiency $V_{s} i_{s} = V_{p} i_{p}$
$\Rightarrow 120 \times 80 = 2400 i_{p} \Rightarrow i p = 4 A$

Q. A step down transformer is connected to 2400 volts line and 80 amperes of current is found to flow in output load. The ratio of the turns in primary and secondary coil is 20 : 1. If transformer efficiency is 100%, then the current flowing in the primary coil will be

1600 amp

20 amp

4 amp

1.5 amp

Np​Ns​​=Vp​⇒201​=2400Vs​​⇒Vs​=120VVs​​ For 100% efficiency Vs​is​=Vp​ip​ ⇒120×80=2400ip​⇒ip=4A

$\frac{N _{s}}{N _{p}} = \frac{V _{s}}{V _{p} \Rightarrow \frac{1}{20} = \frac{V _{s}}{2400} \Rightarrow V _{s} = 120 V}$
For $100%$ efficiency $V_{s} i_{s} = V_{p} i_{p}$
$\Rightarrow 120 \times 80 = 2400 i_{p} \Rightarrow i p = 4 A$