I have a couple 28A stators, that I overhauled.

moddy

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I have soldered the field coil wire (white and black wire is connected to this wire) and stator wires to their perspective places. Re sealed with blue RTV, and leak checked. What I find interesting is I haven't been able to test for voltage. Ohms check out, between all of the connections, so does continuity. I hooked up a drill with a socket to spin the alternator, and am unable to detect any voltage output, the same way you would disconnected the p2 and p3 connector on a running ST. Ground clamp to the alternator housing, positive lead to the stator wires. Any combination actually. So what I'm wondering if any of you have bench tested a stator. To know the voltage output will be correct so all the time placing this thing won't waste someones time.
 
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Dumb question Moddy and probably highlighting my lack of knowledge, but don't you need to feed power to one set of coils to generate power from the others? I don't believe there are any permanent magnets in these, so you need to create a field before any current can flow.


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John OoSTerhuis

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It's not a permanent magnets type alternator. It needs the 12V the black lead at the 2P provides.

Dunno what rpm you need to spin it at... wish I knew (e.g. to bench test a salvage 40amper, using the STOC loaner V-belt pulley adapter).

John
 
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It's not a permanent magnets type alternator. It needs the 12V the black lead at the 2P provides.
Thanks John for that info. Have you tested the 28 amp alternator and if so do you have any advice. I have a good one or at least it was a working one a few years back and want to get rid of it but need to be sure of it's condition.
Bob here in Spokane
 

John OoSTerhuis

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Thanks John for that info. Have you tested the 28 amp alternator and if so do you have any advice. I have a good one or at least it was a working one a few years back and want to get rid of it but need to be sure of it's condition.
Bob here in Spokane
Hi Bob. I have not tested a 28amper off the bike. Note that I added to my post while you posted. I can understand if you're trying to sell your old alt that you'd like to tell the buyer it (the stator) works. But why bother, at this point hardly worth anything and anyone wanting it is probably poor and just trying to keep their ST1100 running. Just give it to anyone "needing" one, as many of us have done and let them test it in situ. Same advice for the VRR, assuming it also was working and you still have it. JMHO

John
 
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moddy

moddy

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don't you need to feed power to one set of coils to generate power from the others? I don't believe there are any permanent magnets in these.
No power should need to be fed to the stator because I'm simulating the p2 and p3 connector disconnected. There are no permanent magnets in the 28A stator.
Here's the thing. When everything is hooked up and running properly, engine is running, left side panel off.

This is a link to an explanation from John Oosterhuis post #3
https://www.st-owners.com/forums/showthread.php?132224-Diagnostic-of-28AMP-failure-VRR-check-confusion

To check the alternator windings disconnect all three of these wires. [unplug the red 3P connector] Set your multimeter to AC current and start your engine with these wires disconnected. Check power between any of these wires and any two wires should have voltage output typically from 50 to 80 volts ac depending on the rpm.


I am getting 200mv ( 1/5 of a volt) in all of my ac lead connections, but the ohms check out. The only thing I can think of, without it being connected to engine is making the difference. Additionally, for this test, if the field coil ( p2 connector) being plugged into the VRR is what I'm mission could be why a higher value of ac volts isn't being generated.
 
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Hi Bob. I have not tested a 28amper off the bike. Note that I added to my post while you posted. I can understand if you're trying to sell your old alt that you'd like to tell the buyer it (the stator) works. But why bother, at this point hardly worth anything and anyone wanting it is probably poor and just trying to keep their ST1100 running. Just give it to anyone "needing" one, as many of us have done and let them test it in situ. Same advice for the VRR, assuming it also was working and you still have it. JMHO

John
Thanks John
I will be doing just that. So anyone reading this can contact me. I will also post it on this forum
 
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moddy

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Moddy, there has to be 12V to create the electro magnetic field to generate the AC current. Have look at this:

https://www.st-owners.com/forums/attachment.php?attachmentid=176155&d=1470526152

Scroll down to "The maintenance free field controlled generator [ST1100 28 amp system]"

John

I'm on my way to read that now. I thought something was missing, not getting the same results, testing at the p3 connector. It was very different with the voltmeter, likely the p2 connector was was still attached, reading the voltage between any two leads at the p3.
 
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To say bench test complete would be an understatement. The only thing missing from a successful output test was a video of me reacting to connecting 12 volts across the black and white wire with the alternator spinning by hand drill, priceless. What I couldn't anticipate was the voltmeter was set test for AC potential, not amps. The drag once I connected the 12 volts was startling. Once the rpm came back up I was seeing 8, 9 and 10 volts between each set of two wires from the p3.
Never (ever) would I have thought to connect 12 volts across the field coil wire because it was such a thin gauge, and all the same wire, but it's a long wire. With my voltmeter set for amps, 12 bolts applied to the field coil was a 3A draw. Now to find someone who wants a working stator for shipping. Cheers
 
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I have soldered the field coil wire (white and black wire is connected to this wire) and stator wires to their perspective places. Re sealed with blue RTV, and leak checked. What I find interesting is I haven't been able to test for voltage. Ohms check out, between all of the connections, so does continuity. I hooked up a drill with a socket to spin the alternator, and am unable to detect any voltage output, the same way you would disconnected the p2 and p3 connector on a running ST. Ground clamp to the alternator housing, positive lead to the stator wires. Any combination actually. So what I'm wondering if any of you have bench tested a stator. To know the voltage output will be correct so all the time placing this thing won't waste someones time.
Hi, just got a replacement 28 amp stator with two broken wires just at the rubber cover, do you have any photos of what is under the cover ( don't want to tear it off if I'm doing more damage) . Was it easy to access all five soldering points ? Am going to try and replace all five leads, any help appreciated, kind regards Dave
 
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Photo from an older post that I saved. Search on ST1100 alternators and find the entire article, a 'rewinding' thread if I recall. The field windings are stripped of insulation and potted at the exit which is under the rubber cap. Stripped wires seal better than insulated wires with this method. The potting/sealing goop is hard and can be removed with a lot of careful picking/chiseling. All this will have to be removed from the wire in order for a good solder repair to be accomplished....then repotted. Some of the posts above have bits of the detail involved.


239478
 

John OoSTerhuis

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Search on ST1100 alternators and find the entire article, a 'rewinding' thread
I clicked on moddy’s avatar and looked at threads he’d started. Here’s that article/thread with the detailed step-by and all the pictures:
 
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Photo from an older post that I saved. Search on ST1100 alternators and find the entire article, a 'rewinding' thread if I recall. The field windings are stripped of insulation and potted at the exit which is under the rubber cap. Stripped wires seal better than insulated wires with this method. The potting/sealing goop is hard and can be removed with a lot of careful picking/chiseling. All this will have to be removed from the wire in order for a good solder repair to be accomplished....then repotted. Some of the posts above have bits of the detail involved.


239478
Thanks for the advice and helpful photo , looks like breaks in insulation ( same as mine ) will go carefully when removing the goop, new wires will be peace of mind as they live in a harsh environment with road salt etc..here in not so sunny Scotland, kind regards Dave
 
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moddy

moddy

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Thanks for the advice and helpful photo , looks like breaks in insulation ( same as mine ) will go carefully when removing the goop, new wires will be peace of mind as they live in a harsh environment with road salt etc..here in not so sunny Scotland, kind regards Dave
I'd forgotten about that thread until now. Probably the most useful thing to know is I used an engraver to battle the resin out. Having replaced the alternator with a 40A I haven't gotten back to this project though I finished the 28A stator, tested it and believe I fixed one of 3 legs that was shorting, just haven't placed it on a motorcycle. I once read that the 28A stator was appealing across the pond due to salt in the air.
 
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