| nighthawk 550 electrical problem [message #470738] |
Sun, 09 October 2005 03:22 |
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krusty kritter Wrote:
> jlpridge wrote:
> -
> Your caution is why I asked before making the decision on this
> one.-
>
> My concern is to help you avoid spending money needlessly on parts
> that
> may
> not need replacement. The charging system, consisting of alternator,
> rectifier regulator, and battery is the system most often
> misunderstood
> and all the parts very often get replaced one at a time until the
> problem is found and the owner gets stuck with perfectly good extra
> parts.
> -
> Yes my alternator has a fan and yes the bike does have a cdi box
> under the seat. The clymer manual says there is not test for that
> box.
> It is either good or bad. Mine is good because the bike fires
> properly
> when the pickup is working correctly. The rotor does turn as I
> suspected.-
>
> Good. Now that we are clear on those points, the only other possible
> reasons why the stator wouldn't put out the required open circuit
> voltage are that the magnets on the rotor have lost their permanent
> magnetism and the distinctly odd ball possibility that the stator or
> rotor is the wrong one for the motorcycle. (1)
>
> It's certain easy enough to find out if the permanent magnet rotor is
> still magnetized, just hold a piece of iron next to it and it will
> grab
> the iron and hold it.
>
> Permanent magnets can lose their magnetism from being heated, being
> struck hard blows with a hammer, or from being exposed to an
> electromagnetic field.
> -
> The test of that black wire and white wire is straight out
> of the clymer manual and it fails the resistance test clearly on a
> cheap multimeter and an expensive one. What I am not sure of is what
> the significance of the resistance between these two leads that makes
> the stator bad.-
> --
> However the test of the resistance between the white
> and the black lead failed. The result in specs would be 4-6 ohms
> whereas mine measures 1 ohm.--
>
> The indication of low resistance is that some of the windings of the
> stator's CDI charging coils are shorted out.
>
> When you run the open circuit voltage test on the yellow wires, are
> the
> black and white wires also disconnected? If the black and white wires
> are disconnected and the engine runs, that indicates to me that the
> CDI
> system will start the engine on battery voltage too.
>
> The indication from the 1 volt you got from the open circuit test (if
> you checked from yellow to yellow to yellow with the engine running at
> around 5000 RPM) is that the stator battery charging coils are also
> shorted out.
>
> The decision to spend $100 on having your stator rewound, is, of
> course
> entirely up to you, and I hope that my explanations have helped you
> make the correct decision.
>
> (1)We read about the strange case a few years ago where the owner of a
> Suzuki GS750 had mismatched the rotor from one motorbike to the stator
> from another motorbike and the number of magnetic poles was incorrect
> so the required north and south magnetic poles were not aligned with
> the stator poles at the correct time and there was no voltage output.
> As I recall, that fellow had one 12-pole part and one 18-pole part,
> and
> that's why the north poles and south poles were never aligned to
> produce voltage in the stator. That one was a real headscratcher.
Krusty,
Well I found out why the stator failed the open circuit test.
My bike does not have magnets on the rotor. The black wire and the white
wire are a positive and negative lead that provides 12 volts to I
believe excite the field or stator providing the magnetism which
normally comes from the magnets and without power to those two wires
there will be no ac output. Nonetheless the stator is bad because the
the resistance on the those two leads is 1 ohm when the specs say that
it should be 4-6 ohms. I found I shop that had one for $65 and it
should be here wednesday.
Jeff
--
jlpridge
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| Re: nighthawk 550 electrical problem [message #470739 ] |
Sun, 09 October 2005 06:16 |
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jlpridge wrote:
> Well I found out why the stator failed the open circuit test.
> My bike does not have magnets on the rotor. The black wire and the white
> wire are a positive and negative lead that provides 12 volts to I
> believe excite the field or stator providing the magnetism which
> normally comes from the magnets and without power to those two wires
> there will be no ac output. Nonetheless the stator is bad because the
> the resistance on the those two leads is 1 ohm when the specs say that
> it should be 4-6 ohms. I found I shop that had one for $65 and it
> should be here wednesday.
Aren't there any brushes that go to slip rings on the rotor?
Do the black wire and white wire go to pins in the same connector that
has the three yellow wires in it? If the alternator is actually an
excited field alternator, the power to excite the the rotor would have
to come from the voltage regulator. So if all those wires are in the
same connector, and you have the connector disconnected to do the open
circuit
test and it would have to fail the test.
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| Re: nighthawk 550 electrical problem [message #470742 ] |
Sun, 09 October 2005 15:17 |
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krusty kritter wrote:
> jlpridge wrote:
>
>> Well I found out why the stator failed the open circuit test.
>> My bike does not have magnets on the rotor. The black wire and the white
>> wire are a positive and negative lead that provides 12 volts to I
>> believe excite the field or stator providing the magnetism which
>> normally comes from the magnets and without power to those two wires
>> there will be no ac output. Nonetheless the stator is bad because the
>> the resistance on the those two leads is 1 ohm when the specs say that
>> it should be 4-6 ohms. I found I shop that had one for $65 and it
>> should be here wednesday.
>
> Aren't there any brushes that go to slip rings on the rotor?
Do you have me killfiled? I already told the OP that there weren't
any brushes and it was a brushless excited field alternator.
http://groups.google.com/group/rec.motorcycles.tech/msg/2ff0 a6db3a6d07fe
> Do the black wire and white wire go to pins in the same connector that
> has the three yellow wires in it? If the alternator is actually an
> excited field alternator, the power to excite the the rotor would have
> to come from the voltage regulator. So if all those wires are in the
> same connector, and you have the connector disconnected to do the open
> circuit
> test and it would have to fail the test.
Yes it would... all five wires to the alternator come through the
same connector, you can see it on the part fiche. There's no substitute
for understanding the basics of electronics and magnetism, I'm afraid.
jlpridge should repeat the open circuit voltage test with the three
stator output wires disconnected, but the black and white wire connected.
He can do this by pulling the connector apart and using two jumper wires
to connect the field coil supply (the black and white wires) across the
two connectors. However, if his measurements of the field coil resistance
is correct at 1 Ohm, and the spec is in fact 6 ohms, the field coil is
bad and he will probably have to replace the entire field coil/stator
assembly. He might be able to rewind just the field coil portion of it,
but $65 for a good field coil/stator assembly is not a bad price at all.
--
Mark '01 SV650S '99 EX250-F13 '86 GL1200A '81 CM400T
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| Re: nighthawk 550 electrical problem [message #470744 ] |
Sun, 09 October 2005 17:06 |
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Mark Olson wrote:
> krusty kritter wrote:
> > Aren't there any brushes that go to slip rings on the rotor?
>
> Do you have me killfiled? I already told the OP that there weren't
> any brushes and it was a brushless excited field alternator.
No, I can't killfile anybody using google groups. I just didn't happen
to read your message, but the idea about a stationary field coil and
transmitting magnetism through the rotating poles makes sense,
explaining how a brushless excited field alternator works.
> > Do the black wire and white wire go to pins in the same connector that
> > has the three yellow wires in it? If the alternator is actually an
> > excited field alternator, the power to excite the the rotor would have
> > to come from the voltage regulator. So if all those wires are in the
> > same connector, and you have the connector disconnected to do the open
> > circuit
> > test and it would have to fail the test.
>
> Yes it would... all five wires to the alternator come through the
> same connector, you can see it on the part fiche. There's no substitute
> for understanding the basics of electronics and magnetism, I'm afraid.
>
> jlpridge should repeat the open circuit voltage test with the three
> stator output wires disconnected, but the black and white wire connected.
> He can do this by pulling the connector apart and using two jumper wires
> to connect the field coil supply (the black and white wires) across the
> two connectors. However, if his measurements of the field coil resistance
> is correct at 1 Ohm, and the spec is in fact 6 ohms, the field coil is
> bad and he will probably have to replace the entire field coil/stator
> assembly. He might be able to rewind just the field coil portion of it,
> but $65 for a good field coil/stator assembly is not a bad price at all.
Yes, I agree with your proposed test procedure.
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| Re: nighthawk 550 electrical problem [message #470745 ] |
Sun, 09 October 2005 17:38 |
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R. Pierce Butler wrote:
> jlpridge <jlpridge.1wm8kp [at] news.motorbikebanter.com> wrote in
> news:jlpridge.1wm8kp [at] news.motorbikebanter.com:
>> Well I found out why the stator failed the open circuit test.
>> My bike does not have magnets on the rotor. The black wire and the white
>> wire are a positive and negative lead that provides 12 volts to I
>> believe excite the field or stator providing the magnetism which
>> normally comes from the magnets and without power to those two wires
>> there will be no ac output. Nonetheless the stator is bad because the
>> the resistance on the those two leads is 1 ohm when the specs say that
>> it should be 4-6 ohms. I found I shop that had one for $65 and it
>> should be here wednesday.
> To be honest I am a little surprised you didn't see any brushes when you
> took it apart. Is it possible the brushes are so badly worn you can't see
> them unless you know what you are looking for?
THERE AREN'T ANY BRUSHES, YET IT _IS_ AN EXCITED FIELD ALTERNATOR.
--
Mark '01 SV650S '99 EX250-F13 '86 GL1200A '81 CM400T
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| Re: nighthawk 550 electrical problem [message #470751 ] |
Mon, 10 October 2005 02:00 |
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Mark Olson <olsonm [at] tiny.invalid> wrote in
news:11kieavbtbqovaf [at] corp.supernews.com:
> R. Pierce Butler wrote:
>> jlpridge <jlpridge.1wm8kp [at] news.motorbikebanter.com> wrote in
>> news:jlpridge.1wm8kp [at] news.motorbikebanter.com:
>
>>> Well I found out why the stator failed the open circuit test.
>>> My bike does not have magnets on the rotor. The black wire and the
>>> white wire are a positive and negative lead that provides 12 volts to
>>> I believe excite the field or stator providing the magnetism which
>>> normally comes from the magnets and without power to those two wires
>>> there will be no ac output. Nonetheless the stator is bad because the
>>> the resistance on the those two leads is 1 ohm when the specs say that
>>> it should be 4-6 ohms. I found I shop that had one for $65 and it
>>> should be here wednesday.
>
>> To be honest I am a little surprised you didn't see any brushes when
>> you took it apart. Is it possible the brushes are so badly worn you
>> can't see them unless you know what you are looking for?
>
> THERE AREN'T ANY BRUSHES, YET IT _IS_ AN EXCITED FIELD ALTERNATOR.
>
You are right. There aren't and I realized that after I posted. Trying to
carry on two conversation and post to usenet just doesn't work well.
pierce
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