THE SPEED OF ROTATION OF A SYNCHRONOUS GENERATOR
The electrical frequency of synchronous generators is synchronized (locked in) with the mechanical rate of rotation. The rate of rotation of the magnetic fields (mechanical speed) is related to the stator electrical frequency by:
![clip_image001[1]](http://machineryequipmentonline.com/electric-equipment/wp-content/uploads/2015/11/clip_image0011_thumb.gif "clip_image001[1]")
THE INTERNAL GENERATED VOLTAGE OF A SYNCHRONOUS GENERATOR
![clip_image001[1]](http://machineryequipmentonline.com/electric-equipment/wp-content/uploads/2015/11/clip_image00111.gif "clip_image001[1]"){kind=small}
The magnitude of the voltage induced in a given stator phase is given by
where K is a constant that depends on the generator construction, cp is the flux in the machine, and w is the frequency or speed of rotation. Figure 12.7a illustrates the relation- ship between the flux in the machine and the field current IF . Since the internal generated voltage EA is directly proportional to the flux, the relationship between EA and IF is similar to the one between cp and IF (Fig. 12.7b). The graph is known as the magnetization curve or open-circuit characteristic of the machine.
