I think you should be aware that generators (dynamos) are quite different to alternators. In a DC generator the field winding is the Stator which is normally fed via a switch. The Rotor contains a number of coils all connected to a commutator (mechanical rectifier) which provides a pulsed DC output. As only a part of the rotor is ever in use the device is relatively inefficient.
In the case of an alternator, which is normally 3 phase, it is mechanically difficult to pick off the 3 phases from the rotor so the design is normally reversed. The Rotor is the field winding fed via slip rings from the Battery using the Alternator switch. The 3 windings of the Stator provide 3 phase ac which is fed to the semiconductor rectifier pack providing the DC output.
The Bat switch connects the Battery to the Busbar. The Alternator switch connects the field of the generator/alternator, with no field, no magnetism, no output.
Trickle charge is usually the term used to describe the charging of a battery not a field coil. By interrupting the field coil current, the output voltage of the generator can be controlled.
A switch is designed to switch a current, the points in it open and close quickly and are wide to prevent the arc from causing excessive pitting. A CB is designed to isolate a circuit not to switch it, if it is used as a switch it will have limited life.
The magnitude and frequency of the emf is proportional to the relative velocity. Alternators will be frequency wild unless operated at a constant speed, that is why the output is rectified to DC where it is more usable. AC power systems in aircraft did not really appear until the constant speed drive was developed.