Sparx alternator problems

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Methinks I have a problem with my newly installed Sparx three-phase alternator... here are the symptoms:

- DC voltage measured across the battery is about 12.45V - and doesn't vary with RPMs. Nor does the headlight get brighter as the engine is revved.

- I have continuity between all three yellow wires from the stator.

- I have no continuity to ground between any of the yellow wires to the stator and ground.

- I have continuity to ground between ONE of the three yellow wires from the regulator - not the other two.

- I get about 8-9 volts AC from each of the three yellow wires from the stator at idle - this increases with RPM. I only took it up to about 2000-2500 RPM, at which point I got about 14 volts AC out of each of them.

Any help will be appreciated! Thanks - Brian
 
Brian:

I just installed the Sparx 3-phase alternator plus regulator on my '75 mark 3 a couple of days ago. Took it for a quick 50 mile ride and just got back a few minutes ago.

Mine works perfectly.

Did you remember to tape off the wires to the Zenor(s)?

And to change the spark plug caps to the 5K ohm type?

My headlight doesn't get brighter as the engine is revved either - but that's not necessarily a bad thing. The Sparx is supposed to be putting out more power at low revs than the stock Lucas single-phase. The stock Lucas puts out more juice as revs go up, thus its noticeable via the headlight getting brighter. Now my headlight is bright at low revs too, so no diff with revs.

Just like my Harley, my Beemer, and car - the way its supposed to be.

All good at my end
 
Hi Keith. Zener's completely gone, and new wiring harness. You may be right about the headlight - but I'm not getting charging voltage across the battery. :-(
 
PS, that 8-9 volts AC from the wires from the stator was measured between those wires and a wire to the regulator - i.e., across the connector. It's more like 14-15 volts AC BETWEEN the yellow wires from the alternator. Which still seems low. But again, NO charging voltage across the battery - not just low, NONE.
 
Brian - my only test so far was to start the bike and take it out for a ride. I didn't do any tests with my multi-meter.

Heading out of town shortly, but will do the same tests as you on Sat. Is yours a 75 Mark 3 also?
 
Thanks Keith, that'd be tremendously useful to me. No mine is a 73 850. - Brian
 
By the way, while overcharging certainly isn't a problem yet, hopefully I'll soon have to at least consider it. I'm using resistor plugs - do I really need 5000 ohm resister caps also? I believe resistor plugs themselves provide 5000 ohms of resistance - do I need 10K??
 
BTW, I dropped Sparx an email about the resistor caps, and they responded that it's okay to use EITHER 5000 ohm caps ("which is best") OR resistor plugs.
 
BrianK said:
BTW, I dropped Sparx an email about the resistor caps, and they responded that it's okay to use EITHER 5000 ohm caps ("which is best") OR resistor plugs.

When I bought my Sparx alternator (not installed yet) I was told to also buy resistor plugs and resistor plug wires as well.
 
Spoke with Matt Rambow at CNW about the charging problem. He suspects the regulator and is being kind enough to send me another. I'll fit that up and report back - hopefully that will cure the problem and allow me to move on to ... the next one....!
 
BrianK said:
Methinks I have a problem with my newly installed Sparx three-phase alternator... here are the symptoms:

- DC voltage measured across the battery is about 12.45V - and doesn't vary with RPMs. Nor does the headlight get brighter as the engine is revved.

- I have continuity between all three yellow wires from the stator.

- I have no continuity to ground between any of the yellow wires to the stator and ground.

- I have continuity to ground between ONE of the three yellow wires from the regulator - not the other two.

- I get about 8-9 volts AC from each of the three yellow wires from the stator at idle - this increases with RPM. I only took it up to about 2000-2500 RPM, at which point I got about 14 volts AC out of each of them.

Any help will be appreciated! Thanks - Brian

What sort of plugs, caps and plug wires are you using? I had a very similar problem recently on a 1961 Matchless G12 that I rebuilt. Put on a Boyer ignition, new high-output SPARX alternator and electronic regulator but wasn't getting any charge. Same symptoms as you describe. Turns out that some ignition suppression is good (5 ohms I think) but more than this can interfere with regulator output. Seems to depend where regulator is mounted relative to plug wires. I was using both suppressor wires AND suppressor caps which was somehow fooling the regulator into putting out lower voltage. Once I traded out the suppressor wires for copper core, the battery was charging fine! With the SPARX 220W alternator, you supposedly need exactly 5 ohms of resistance to prevent overcharging. So you should use ONE of either resistor plugs, resistor caps or resistor wires. More is definitely not better!!
 
I have also heard that one must be very careful with the routing of all the wires. This relates to box location as well. Just because they all come out of the same box doesn't mean they can than run parallel to one another.
 
Thanks guys. I have resistor plugs in, but non-resistor wires and caps - 8mm pure copper wires. Glad to hear that's enough (Sparx thought so too, although they prefer non-resistor plugs with resistor caps for some reason) as in general, resistance doesn't strike me as a good thing.

Anyway, given the continuity between one of the regulator wires and ground, Matt Rambow thinks its probably a faulty regulator. He's sending me another, which I'll try in the same configuration and report back (to him and all of you). Hopefully, that's all it is.

I'm just glad I checked the charging voltage after installing, instead of assuming all was well until I ran down my battery on some long ride....

Appreciate everyone's input, and again, will report results of a regulator swap.
 
The promised report: Received a replacement regulator from CNW today (thanks Matt!), swapped it in, and voila! - problem solved.

Thanks again to all who offered advice and/or sympathy. - BrianK
 
Hey Keith, did you ever put a multimeter to yours? I'd be curious how much voltage it was pumping out. Once sorted, mine as in the low to mid 14s AT IDLE. Revving it pushed it up to 14.92V. Seemed a bit high. I did not have resistor caps on the plugs at that point (just resistor plugs). I'm getting a set but they haven't gotten here yet. Thanks - B
 
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