284 
Transactions of the Royal Society of South Africa. 
figure it will be clear that the actual value of the voltage will depend upon 
time of short-circuit of 
This ratio depends upon the original 
the ratio . „ . ^. _ 
tnne oi insertion oi 7\ 
position of 0^. For it was x-^, hence for the mean voltage will be Vq, 
round which the voltage will now pulsate. The above ratio is considerably 
increased, as the figure clearly shows. The exciting current of the exciter 
and thus the exciter voltage pulsating about mean values, the generator 
excitation will do likewise. The generator voltage is, however, affected very 
little, as the pulsations are damped out before they reach the bus bars. 
Consider next the position of lever Ag. The arrangement must be such 
that for the same voltage Yg of the generator the pull on core C3 is inde- 
FiQ. 8. — Regulation with a fast regulator. 
pendent of the position of This means that we cannot use springs for 
balancing purposes, but must employ weights. ' In the figure the weight of 
the core itself balances the magnetic pull. 
When the generator pressure drops the lever will immediately rotate 
clockwise, bringing contacts K^K^ closer together. The reverse action takes 
place for pressure rises. It is thus only for the normal network pressure 
that lever is in equilibrium, but then in any position. The process of 
regulation is thus as follows : 
For normal generator voltage the lever hn is in equilibrium and hi 
vibrates. When the generator voltage drops lever h^ rotates clockwise and 
brings there])y contacts K^K., closer together, forcing its movement also 
upon h^, so that is short-circuited for a longer period than before, until 
