Car alternator to PMAC?

[j bjork]

Another thing that seems strange is it seems to always want to spin in reverse. Every time I have set it up on the nuc it spins in reverse, but there I can just change direction. And I just connect the phases and halls in any order and run self learn.

On the cheap controller I have found a few combinations where it spins fine in reverse, but only bad running forward.
I might have missed some combination possibly, but it sure seems a lot harder to find a good forward combination.

 

[ShadowNightmares]

Another thing that seems strange is it seems to always want to spin in reverse. Every time I have set it up on the nuc it spins in reverse, but there I can just change direction. And I just connect the phases and halls in any order and run self learn.

On the cheap controller I have found a few combinations where it spins fine in reverse, but only bad running forward.
I might have missed some combination possibly, but it sure seems a lot harder to find a good forward combination.

Well, i tried to search for hall sensor problems, maybe you could search on RC filters for the signal
https://electronics.stackexchange.com/questions/419166/3-phase-bldc-hall-sensor-problem

 

[ShadowNightmares]

Another thing that seems strange is it seems to always want to spin in reverse. Every time I have set it up on the nuc it spins in reverse, but there I can just change direction. And I just connect the phases and halls in any order and run self learn.

On the cheap controller I have found a few combinations where it spins fine in reverse, but only bad running forward.
I might have missed some combination possibly, but it sure seems a lot harder to find a good forward combination.

Also, Austiwawa's video talks about the 36 possible combinations of hall sensors and phases, did you tried all of those 36 and put it in an Excel spreadsheet?

 

[monette999]

Hello DIY kollegues,
may I ask a question in this interesting discussion.
How do I find the correct sequence for synchronize rotor to stator.
I was able to set my falling edge and rising edge on the zero crossing of my sensor signal. How do I find stator U to Rotor Sensor U by test.

Here my test setup to set zero crossing.
How do I find UVW Stator to UVW Rotor by measure not by jepardy.

Sensor System works. When I attached it to the controller I had fail starts and that should not be!

Greetings Robert

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[monette999]

Pictures and gif update

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[j bjork]

My alternators have all been 6 pole pairs, your sensor wheel seems to be for 8 pole pairs?

 

[monette999]

Yes that is correct! Can you help?

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[j bjork]

Well, the signals from your sensors wont match the position of the magnets on the rotor if it is not the same number.

 

[monette999]

I have a 8 polepair rotor not 6 as others may have

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[fechter]

I was able to set my falling edge and rising edge on the zero crossing of my sensor signal. How do I find stator U to Rotor Sensor U by test.

Unfortunately, this varies depending on what controller you are using. They are not consistent about the labeling. The only way I know is to trial-and-error using limited current so you don't blow anything up.

The optical encoder looks great!

 

[monette999]

Hi is the spike on the lower measurement the EMF feedback pulse?

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[monette999]

I did something like that many years ago to build a hydroelectric generator. I used some old ceramic speaker magnets that took up the space of the original field coil. One thing I found is the original shaft is magnetic, which shunted away most of the magnetic field. I had to make a non-magnetic shaft from stainless steel. After that it worked reasonably well until the bearings rusted out. But the ceramic magnets are really too weak to make a decent motor. And they get easily demagnetized by high currents.

That was before neodymium magnets were affordable. Now what I see people do is use multiple smaller magnets in a ring around the shaft. Get the right length so the rotor halves are the right spacing. On yours, there is a cylindrical core around the shaft that would have to be removed to make room for the magnets. On mine it was a separate piece that came out with the field coil. You'd still have the issue with the shaft being magnetic.

The skewed "claws" aren't optimal for a motor but should make it a bit quieter.

Do you have a recommendation about the arc spacing on a rotor magnet?

I would like to prefer the 25mm magnet and using metal clips to clamp the magnet.

The 28mm can be only glued that difficult.

Here my ideas of my rotor conversion to PM.

Greeting.
Robert

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Maybe we can make a group buy of these magnets.

 

[Vbruun]

Maybe IPM Will be easier to manufacture?

If the tolerances are good, laser cut metal sheet and flat magnets can be used.

 

[monette999]

What is IPM?

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[Vbruun]

https://youtu.be/nOwB3tqWlk0

 

[monette999]

That's a nice motor but it must be very expensive. The sales video wasn't cheap.
Good Marketing.

I am happy with my alternator,

15 Euro a piece, from Shebay.
and with a sensor system it works well, so 50km/h is not a problem on a 20S 8p configuration.


Greeting

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[Vbruun]

What I am talking about is the way the magnets are imbedded in the rotor in stead og glued om top og it. With this design, IPM, there is No need for rounded permanent magnets.

 

[monette999]

Yes I saw that but how an a private engineer with limited equipment build such a rotor case. It look like precision stamping of the Eddie Current Rotor Housing with slides square magnets.
For this build you need a sequential stamping line with integrated welding.

I don't have this at home.

Thanks.


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[Vbruun]

Afaik there is No need for laminations because the rotor is stationary compared to the rotating magnetic field.

I was thinking that laser cut plates could be bought with slightly oversize holes for magnets which could be glued in so they dont slide.

Then the blocks central Hole for the shaft can be taken to size on a lathe.

But yes quite the project!