Of the system is dependent on the type of load. Filament lighting, heating and cooking will be at unity power factor, but induction motors, fluorescent lighting and transformers will take less than unity. 1 Variation of excitation for constant voltage proportional to the output. f. as high as possible, it is important not to install over-size motors. 4, when starting direct-on-line, when the current is 4-6 times the full-load current. c. motors may take curent at virtually any power factor between zero lagging and almost unity, depending on the firing angle of the thyristors.

Discrimination will have been achieved if the second curve does not cross the generator circuit breaker characteristic. It would, of course, have been possible to make a similar comparison by constructing a second generator circuit breaker characteristic in which each point is displaced by subtracting 600 A. 7, where it will be seen that the apparent discrimination between the generator breaker and the 200 A fuse may in fact be lost for feeder currents up to 900 A when the generator standing load is taken into consideration.

This will limit the degree of damage caused by the fault current and will also serve to maintain system stability. Steady load circuits BS 88 defines these as 'circuits involving apparatus the load of which does not fluctuate much above its normal value'. A heating circuit would be a typical example. Such circuits are unlikely to have any protection additional to the main fuse or circuit breaker. ) protecting such a circuit should be selected to have a rating equal either to the load rating or to the first standard rating that exceeds this.