To test the stator with the rectifier, wire in the rectifier to all ac phases (usually three phase) and set your volt meter to DC volts. Measure across the output of the rectifier. you should see a slightly higher DC voltage than the AC on the input (1.4 times more, to put it simply). This however does not take into account rectifier losses.
If you say you only have 5 volts between legs, at what RPM are you testing? When you short out the phases, is the alternator very hard to turn? Is this a dual rotor axial flux machine?
Please provide more information.Have Fun!! RoyR KB2UHF
What magnets did you use, and whats the air gap?Have Fun!! RoyR KB2UHF[ Parent ]
Even the speed is vague. I have no idea of as "fast as I can ", I think over the years I have developed the knack of cranking things up to just over 300 rpm. That is likely to be fairly high so with the voltage figures given this still could be suitable for a small alternator. You give no idea of size of intended blades so again no help possible without much more information.
Flux[ Parent ]
I am not sure how you are connected. If that 5v is from the coils of one phase then when you star connect it it will give 5 x 1.7v. Then when you rectify it will give that x 1.4v
This will give you 11.9v so with the rectifier drop your cut in is a bit over 200rpm. A bit on the high side but it will work.
If you only have 5v ac with the star connection then you are really low.
The magnet pull is meaningless, just forget it or tell us the neo grade. The air gap is not .07" it will be the distance between magnets ( 2 x .07 plus stator thickness). If your stator has got much too thick due to bad winding or potting this will reduce volts.
The meter will be near enough at 200 rpm. The discussion about waveform and inverters is valid for what they are discussing but your waveform will not be far removed from a sine wave unless you have done something wrong.
Have you brought out 6 leads or have you done the star connection inside, I just don't know what you are measuring for sure.
