Re: Questions about rotor inside common genset like in Indonesian video

Body

Hi Kone,

As the rotor has to make a rotating magnetic field the diode is probably for DC magnetizing the core. The small permanent magnet is for making the generator self-magnetizing. The small magnetic field is enough for getting the current started. After that the field is amplified by the current going through the rotor coil. This way it starts generating without needing a battery like car alternators.

In a car alternator https://wiki2.org/en/Alternator an electronic regulator is used to DC magnetize the rotor by controlling the current for regulating the output voltage.

The image is taken from here: http://www.tb-training.co.uk/marinee08.html http://www.tb-training.co.uk/marinee08.html

The Indonesian device must have something for controlling the speed to prevent it from keep on speeding up until destruction. When he says it isn't simple this can be because of rewinding or some kind of regulator etc.

The next image is showing the regulator in the top left corner.

This image is pasted from here: http://nolanwebdev.com/2718/oQ6e-2733/ http://nolanwebdev.com/2718/oQ6e-2733/

Perhaps the Indonesian guy is taking the voltage directly from the stator coils (AC output) and has the regulator substituted by one that monitors the frequency as well as the voltage. Or the motor has a speed controller to keep the frequency constant. But why it is over-unity is still a question. Is it the motor or the generator or the combination that makes it OU?

Regards
Ole
 

---In [email protected], <konehead@...> wrote :

 Hi all
 
 In attachments are two photos of the insides of one of those 750W usually gas-engine powered gensets just like the guy from Indonesia has on the right side of his motor generator.
 I see the slip rings, I see the 2-pole rotor (so this will take 3600rpm to make 60hz) and inside the plastic housing on one end of the rotor is a diode (actually there are two) and these connect to the ins and outs of the coils somehow....I would think these diodes are sort of "blocking" (big zener?)diodes so that the generator will not produce power until it gets to speed of 3600rpm and makes the 120VAC  or the 220VAC and only then will it let power pass through, so this is a feature to make sure the generator only produces 120VAC and nothing less, especially during start up or warm up and a load is attached to the generator....
 

 Is this correct about those diodes??? Or are they something else?
 

 The other question is about that little ceramic magnet imbedded into the rotor you can see in the photo in attachments....so what exactly is this for??
 To help magnetize the core a little bit and give it some polarity perhaps?
 Why is there only one?
 Is there a hall effect somewhere on stator or small coil that this reacts too and serves as some sort of over-speed governor? (guessing)
 

 Maybe it helps smooth out the sinewave somehow? (but why only one?)
 

 Anyways this is exactly what is inside the Indonesian genset seen in video to the right of the looping motor generator....
 

 perhaps he put in his own rotor of permanent magnets and that is part of it all???
 If anyone can answer my questions it would be appreciated...I hope you can all see the photo attachments...
 ciaoKone