Odd test results for Buick alternator to motor conversion.

cboy

100 W
Joined
Sep 18, 2017
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181
Location
CA Central Valley
I have a brand new 2017 Buick Regal alternator which I intend to convert to a brushless motor. I opened it up and found 6 wires from the stator coils to the diode plate. I assumed (as with other alternator conversions I've seen and done) the six wires would be the "entry" and "exit" wires for each coil and a multimeter would find three sets of two wires which would have continuity. What I discovered was something I'd never seen or heard of before. For the sake of describing the issue I've labeled the 6 wires A1, A2, B1, B2, C1, C2. Test results with a multimeter show the following sets of wires have continuity:
A1 and A2
A1 and B1
A2 and B1
C1 and C2
C1 and B2
C2 and B2
Looking at it a little differently it would appear A1, A2 and B1 are connected and C1, C2 and B2 are connected. One further bit of information wires A1 and A2 emerge from the stator very close to one another. Wires B1 and B2 emerge close to each other as well and about 120 mechanical degrees from the "A" set. Wires C1 and C2 emerge close together and about 120 mechanical degrees from either the "A" set or the "B" set of wires. BTW this is Denso alternator #1042101960. Does anyone have experience with alternator wiring which produces similar test results and what it means for how this alternator stator is wired? It almost appears to me that it is NOT three phase but rather some other configuration.
 

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  • buick stator 2.jpg
    buick stator 2.jpg
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I'm going to answer my own question...after a good deal of on-line research and the help of a Denso technical manual. Turns out this is a dual wound stator wired in the Wye configuration. According to Denso the dual windings were an innovation begun around the year 2000 and are meant to cancel out magnetic fluctuations in the stator. In any event, all six wires pictured in my photo are "entry" wires, three each for each of the dual windings. Wires marked A1, A2 and B1 are the entry wires for the first set of windings and wires marked B2, C1 and C2 are the entry wires for the second (dual) set of windings. All "exit" wires for each of the two windings are terminated together in the stator. This now makes perfect sense of my original multimeter testing which had me baffled. I should also point out from my searching around that Denso configures some of its dual wired alternators in the delta format and the wire identification will be different. If anyone runs into this issue while converting a 2000 or later alternator there is a terrific explanation of dual windings along with very clear diagrams and wire identifications at https://assets.denso-am.eu/production/attachments/Starter-Alternator-Manual-English.pdf
 
Nice, thanks for the reference.

Looks like good copper fill for a hairpin wound motor.

Do you know the stator lamination thickness?

Any pics of the rotor? are you keeping the field windings for field weakening? or convert to perm magnet.
 
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