Q1 A factory load consists of the following :
(i) an induction motor of 50 H.P. (37.3 kW) with 0.8 pf and efficiency 0.85.
(ii) a synchronous motor of 25 H.P. (18.65 kW) with 0.9 pf leading and efficiency 0.9.
(iii) lighting load of 10 kW at unity pf.
Find the annual electrical charges if the tariff is Rs 60 per kVA of maximum demand per annum plus 5 paise per kWh ; assuming the load to be steady for 2000 hours in a year.
Q2 A supply system feeds the following loads
(i) a lighting load of 500 kW
(ii) a load of 400 kW at a pf of 0.707 lagging
(iii) a load of 800 kW at a pf of 0.8 leading
(iv) a load of 500 kW at a pf. 0.6 lagging
(v) a synchronous motor driving a 540 kW d.c. generator and having an overall efficiency of 90%. Calculate the power factor of synchronous motor so that the station power factor may become unity.