S. L. Arora Solutions for Chapter: Alternating Current and Electrical Machines, Exercise 8: Problems For Practice

A transformer has $300$ primary turns and $2400$ secondary turns. If the primary supply voltage is $230\mathrm{}\mathrm{V}$. What is the secondary voltage?

A transformer has $200$ primary turns and $150$ secondary turns. If the operating voltage for the load connected to the secondary is measured to be $300\mathrm{}\mathrm{V},$ what is the voltage supplied to the primary?

The ratio of the number of turns in the primary and the secondary coils of a step up transformer is $1:200.$ It is connected to a.c. mains of $200\mathrm{}\mathrm{V}.$ Calculate the voltage developed in the secondary. Determine the value of maximum current in the secondary, when a current of $2.0\mathrm{}\mathrm{A}$ flows through the primary.

How much current is drawn by the primary of a transformer connected to $220\mathrm{}\mathrm{V}$ supply when it delivers power to a $110\mathrm{}\mathrm{V}-550\mathrm{}\mathrm{W}$ refrigerator?

Given the input current $15\mathrm{}\mathrm{A}$ and the input voltage of $100\mathrm{}\mathrm{V}$ for a step-up transformer having $90\%$, efficiency, output power and the voltage in the secondary if the output current is $3\mathrm{A}.$

The primary of a transformer has $200$ turns and the secondary has $1000$ turns. If the power output from the secondary at $1000\mathrm{}\mathrm{V}$ is $9\mathrm{}\mathrm{k}\mathrm{W}$, calculate (i) the primary voltage and (ii) the heat loss in the primary coil if the resistance of primary is $0.2\mathrm{}\mathrm{\Omega }$ and the efficiency of the transformer is 90%.

A town situated $20\mathrm{}\mathrm{k}\mathrm{m}$ away from a power plant generating power at $440\mathrm{}\mathrm{V}$, requires $600\mathrm{}\mathrm{k}\mathrm{W}$ of electric power at $200\mathrm{}\mathrm{V}$. The resistance of the two wire line carrying power is $0.4\mathrm{}\mathrm{\Omega }\mathrm{}\mathrm{p}\mathrm{e}\mathrm{r}\mathrm{}\mathrm{k}\mathrm{m}$. The town gets power from the line through a $3000\mathrm{}-\mathrm{}220\mathrm{}\mathrm{V}$ step down transformer at a substation in the town. (i) Find the line power losses in the form of heat. (ii) How much power must the plant supply, assuming there is negligible power loss due to leakage?