1. Why is there phase difference between voltage and current in an a.c. circuit ? Explain the concept of power factor.
2. Discuss the disadvantages of a low power factor.
3. Explain the causes of low power factor of the supply system.
4. Discuss the various methods for power factor improvement.
5. Derive an expression for the most economical value of power factor which may be attained by a consumer.
6. Show that the economical limit to which the power factor of a load can be raised is independent of the original value of power factor when the tariff consists of a fixed charge per kVA of maximum demand plus a flat rate per kWh.
7. Write short notes on the following :
(i) Power factor improvement by synchronous condenser
(ii) Importance of p.f. improvement
(iii) Economics of p.f. improvement
8. What is the importance of power factor in the supply system ?
9. Why is the power factor not more than unity ?
10. What is the effect of low power factor on the generating stations ?
11. Why is unity power factor not the most economical p.f. ?
12. Why a consumer having low power factor is charged at higher rates ?