48 volt Direct Drive PM Alternator Assembly

[Henry W]

It will be ok, These PM alternators blow lots of air out of the housing.

[SPSInc]

Henry,

Glad to see it made it and fits properly. Looks great. I don't think you will have any issues with heat transferring to the PM for the muffler.

[Frank S]

I would like to have some detailed information on these generators so far googling hasn't turned up much in the way of useful stuff

[SPSInc]

Frank S,

I don't think anything was ever published on these PMG ends. They were mainly used on products built by the generators manufacturer and never sold to end users as a piece part. I do have some good knowledge of the generators and have some on hand in various fashions. I'd be willing to share some info about them if you have some particular questions. I wouldn't have the time to develop a full analysis and spec sheet but could answer some general questions.

[Frank S]

Frank S,

I don't think anything was ever published on these PMG ends. They were mainly used on products built by the generators manufacturer and never sold to end users as a piece part. I do have some good knowledge of the generators and have some on hand in various fashions. I'd be willing to share some info about them if you have some particular questions. I wouldn't have the time to develop a full analysis and spec sheet but could answer some general questions.
[/quote
I was just curious as to whether or not there happened to be any white papers or prints available for these or if in what ever generators they were used in if there happened to be any drawings or wiring schematics or drawings on them
I think I can see 74 slots in the stator if so how are the coils wired, how many coils with X number of turns per coil.
My primary reason for asking is this unit looks to be a perfect platform for a scale model of a larger generator I am designing which I am hoping to wind up with a 48 pole 100 to 150 RPM 500v 25 to 30KW poly phase unit  but rather than spend $5000.00 to $15000.00 on prototyping a full sized unit only to find that I totally messed up one of these might be something to work with at scale.
Correct me if i am wrong but were these exciter ends for a brush-less generator

[mobile_bob]

iirc the units are reported to be 24pole, and as such are likely 24pole 3phase
which works out for the number of slots available in the stator.

just guessing here, but  i would expect something on the order or 9 to 12 turns per pole
of ~15 gauge wire?

although i am leaning toward the lower end of the turn count, the need for very low resistance
to get ~90% efficiency i very important.. i can't see the turn count being higher without a loss of
efficiency, which adds up pretty quickly in my experience with increased turns equating to increased
resistance.

also iirc the stator is Y connected, and as such its voltage will be 1.73 times what it would be delta connected,  and Y connected has a higher resistance, so maybe the turn count is less than 9 per pole.
Being Y connected they might be a bit larger gauge? 

then there is the thing about being double wound, so that they can be connected hi Y or low Y, so the turn count per pole might appear to be ~18 but the reality is really two sets of ~9 turns per each pole.

can't wait to get my grubby mitts on one, and see how it is laid out, lets see how close i am in guessing how they are designed.

bob g

[SPSInc]

Bob you are right on track. Only thing would be that the windings are wound using many parallel small gauge wires in order to get a high density slot fill. They were wound with as much copper as possible for low I²R losses.

[mobile_bob]

ok, so its wound "multiple in hand"  but what is the effective turn count per pole?

makes sense in order to get the maximum slot fill and as you state lower resistance, something
others do with some frequency when it come to getting as much power out of a unit possible.

very cool unit indeed

bob g

[Frank S]

Bob your explanation was fitting along with what little knowledge I have about turn to Gage to resistance And I had read about the duel voltage  connection What was puzzling me was in the photos the wire size looks more like 20 or 22 Gage or maybe even 24 . its a little hard to scale from the angles of the photos
The explanation of multiple small parallel wingdings makes more seance to me than anything I was thinking otherwise I would have thought the voltages judging by the amount of strands I can see would have seemed more in the 200 to 250 V range
I'm with you I would love to get my hands on one or more. But I haven't seen anything similar to them over here yet.
I visit lots of scrap places, all of which are located with in 2 miles of my factory and have now printed a couple of pictures to show what I am looking for maybe I will have better luck the next time I make my rounds, and I may have to extend my search to several of the motor wind shops that I know of about 30 miles from me. the problem with looking for some particular item is the scrapers want to quadruple the price if they think you need something.

[SPSInc]

Hi Bob, I don't have the exact turns count but I think it is closer to 5 turns than 9. I believe it is 24AWG wire. The low voltage generators probably have 15-20 wires in hand and just a few turns. The high voltage gen have just a few wires in hand and many turns per poles. The high voltage versions only came out with about 16ga leads.

[mobile_bob]

thanks for the count

that is good info to me

bob g

[SPSInc]

bentcrafter - Here is the information you requested. This is a low speed test of 2 different stators I have. I kept the output voltage at 28Vdc and adjusted the speed of the engine according to load. The blue graph is the smallest stator stack/rotor combination I have and the red graph is the largest stator stack/rotor I have. I could mix & match to move those lines some to match your engine HP. I did not max out the red curve. I was only looking for 150 Amps when I did this test last time so I didn't reach the alternators limits. On the blue curve you can see the slope is getting vertical meaning it is at its max.