A step up transformer operates on a 200 V line and supplies to a load of 2 A. The ratio of primary to secondary windings is 1: 25. Determine the primary current.

Question

A step up transformer operates on a 200 V line and supplies to a load of 2 A. The ratio of primary to secondary windings is 1: 25. Determine the primary current. (A) 8.8 A (B) 0.08 A (C) 12.5 A (D) 50 A

Tardigrade Admin · Accepted Answer

In a step-up transformer Power in secondary

=

Power in primary

V_{s} i_{s} = V_{p} i_{p} \dots

(i)
Also, from transformation ratio

\frac{V _{s}}{V _{p}} = \frac{N _{s}}{N _{p}}

Given,

\frac{N _{p}}{N _{s}} = \frac{1}{25}

,

V_{p} = 200 V

∴ V_{s} = 200 \times 25 = 5000 V

From Eq. (i),

5000 \times 2 = 200 \times i_{p}

\Rightarrow i_{p} = 50 A

Q. A step up transformer operates on a 200V line and supplies to a load of 2A. The ratio of primary to secondary windings is 1:25. Determine the primary current.

8.8 A

0.08 A

12.5 A

50 A

In a step-up transformer Power in secondary = Power in primary Vs​is​=Vp​ip​…(i) Also, from transformation ratio Vp​Vs​​=Np​Ns​​ Given, Ns​Np​​=251​, Vp​=200V ∴Vs​=200×25=5000V From Eq. (i), 5000×2=200×ip​ ⇒ip​=50A

Q. A step up transformer operates on a $200 V$ line and supplies to a load of $2 A$ . The ratio of primary to secondary windings is $1 : 25$ . Determine the primary current.