Question

The step-down transformer in a local neighborhood reduces the voltage from a 7,200 V line to 120 V. (a) If there are 125 loops on the secondary, how many are on the primary coil? (b) What current does the transformer draw from the line if the current in the secondary is 36 A? (c) What are the power input and output?

Answer 1

Answer:

a)7500Loops

b)0.6A

c)4320W

Step-by-step explanation:

Hello, first we will define the concept of transformer, it is an electric device that works with alternating current capable of changing the voltage and current levels while maintaining energy. for the transformer we have the following equations

$\frac{Np}{Ns}=\frac{Vp}{Vs} =\frac{Is}{Ip}$

where

Vp=

primary voltage=7200

Vs=secondary voltage=120

Np=

primary loops

Ns=secondary loops=125

Ip=  primary current

Is=secondary current=36A

a)

$Np=\frac{NsVp}{Vs}\\Np=\frac{(125)(7200)}{(120)}= 7500$

b)

$\frac{Vp}{Vs} =\frac{Is}{Ip}\\\frac{IsVs}{Vp}=Ip\\\frac{(36)(120)}{(7200)}=Ip\\\\Ip=0.6A$

c)

A transformer is characterized in that the power is the same in the primary and secondary

P=VI=(Is)(Vs)=(Ip)(Vp)

P=(120)(36)=(0.6)(7200)=4320W