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dead alternator ohms reading????


buggerit
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hi guys very green on electrics here so can you help?


i have :


new battery


new reg/rec


the bike almost didnt start on way home so its now charging off the bike after showing only 11.5v on multimeter before taking it off i revved it to 5,000 revs and got very little extra maybe up to 13 as apposed to 14.5-15.5v when i first got the battery and was at full charge.im not even sure it hit 13 remembering back now! anyway ive stripped back the wires on alternator because i suspected a rotten connector and put the negative and positive leads in ohms setting across the 3 yellow cables. with no battery in im getting 0.00 ohms im guessing this means is dead am i right?? i also checked ground and got 1 all round. to double check after battery is charged i will re test and if its buggered im guessing it wont move or very little!:scratch:

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Check each of the yellow wires compared to ground. If you have 0 ohms you have a short to ground. Continuity between the yellow wires should be more than 0 ohms as well. The exact value will be in the service manual for your bike.


It does sounds like your stator is duff

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copied from the above link


this is only a bit of it there is loads more :lol:


happy reading

 

This is primarily about upgrading the standard equipment Regulator/Rectifier with a more efficient component. You can do this in event of failure rather than replace with the same stock component, or you can even do as a preventive measure if desired.


As a prologue, let me introduce a basic diagnostic troubleshooting process to determine whether you have a charging system failure.


A good Multi-Meter is a pre-requisite.



Record your battery voltage under the follow conditions

1) Ignition off, unloaded battery.

2) Ignition on, headlights on, not running

3) Bike started, running at idle


For condition 1, should be at least in the high 12.x range if fully charged.


In condition 2, your voltage should not drop much below 12.0 at worst. (It may continue to drop – hopefully slowly! – as your lights will be discharging it. However this should be a slow decline)

If it does drop immediately into the 11’s, your battery is insufficiently charged – if it was just charged from a battery charger however, then it indicates your battery no longer has sufficient capacity to retain charge/supply current to load and should be replaced.


Condition 3 is what we are most interested in with respect to charging capability.

Voltage should be at least in the 13’s at all engine rpm. You may detect it will fall off slightly as you raise engine rpm. This is not atypical performance. A simple mod that can enhance your charging voltage to the battery can be achieved by this modification outlined in this thread. That should give you performance in the 14V+ range.


What if you have less than 13V?

First thing to check is the fuse – this may have a different number depending on which model you have, so I will refrain from identifying a specific one. Ask on the forum for your particular model which one you should check if in doubt. It will be a 30A fuse however.


Next, examine the wires and connectors between the stator output and the R/R input (three wire harness and connectors) – are these charred/melted due to excessive heating? That is an early indication that you may have a shorted diode or SCR in the R/R. The regulator is a shunt device and if one of those components goes bad, then it will pull maximum current from the stator. This may not be immediately apparent as you will possibly still see in excess of 12V at idle (possible higher at other rpm) but it will be obvious from the heat and associated burning smell!

This is an unfortunate situation – there is strong possibility that the stator will also be killed by this type of primary failure, if not detected immediately and continued to run in this condition.

A ‘cold’ resistance check for shorted diode/SCR:

Unplug both input & output plugs from R/R;

With your meter set to read resistance (use a diode test if the your multi-meter has one), test from each pin of the three pin plug, to both the red & black wired pins of the 4-pin plug; NONE of these should read short circuit (zero resistance); depending which way you bias the test leads, you may get some reading (from the forward bias of the component) but it must absolutely not be a short. If you see a short on any of these readings the R/R is defective.


Next, do a resistance check on the stator (check at the cable connector going back towards the stator itself).

Measure between the three respective combinations of the three pins:

1-2

2-3

3-1

This time each of these should measure almost short circuit (very low resistance in order or about 1 ohm)

Also check from any one pin to the engine ground terminal – this should not read any indication – maximum resistance or open-circuit.

If you read ‘short’ in that last test, then your stator is bad.


Check the AC voltage output from the stator with engine running:

Leave stator disconnected from the R/R and start the engines.

With meter set to read AC Volts check

1-2

2-3

3-1

All three should be the same value – any significant difference of one reading will indicate a bad phase and the stator is probably defective.

At idle this should be ~ 25V and rise to ~ 70V at 5K rpm. I almost hesitate to use absolute numbers here as this can be different between models and test equipment.

What you are looking for is same between phases and like increase on each phase as rpm increases. If one of the phases illustrates a value that is lower than the other two, that is string indication of a burned stator coil.

If any of the above tests raises suspicion, pull the cover & inspect the stator. It is simple to do and can set your mind at ease by seeing what it looks like. Hopefully NOT with 1/3 of it a black charred mess!


If you have to replace the stator and R/R, especially because of a shorted R/R and excess current drain, be especially careful to ensure that your wiring has not been compromised. If the wiring has been fired, then you will continue to have issues and potential failure of those expensive components which have just been replaced! Replace any cable &/or connector plug that is not in optimum condition.

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this is really useful thanks, it does suggest it may be the alternator but im checking the rec/reg again. not sure if im doing it right but reg/rec disconnected and multimeter cable on each pin in ohms mode i should get something shouldnt i ???

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Checking the Reg/Rec with a meter is a different ball game........there is a diode array (bridge) on the input from the alternator........and diodes will read different depending on which way round the meter leads are......approx 1kohm in the forward direction and pretty much infinite in the reverse direction.......and then the regulator bit will depend on the type of regulator and the components used in it.....so you'd need a diagram of the Reg/Rec really to be able to check that out..... :wink:


But, as the thing Stu sent you says......basically between the stator wires you should get less than 1 ohm......but between each of the stator wires and ground (chassis) you should get infinity (near enough)..... :wink:

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thanks Tango the rec/rec testing seems over my head ha. its one of those things i would have to watch someone do it. the manual shows a diagram but it might as well be Chinese!

the alternator test with the pins on ohms came back as 0.00hms and with a ground and pin test it was 1 with all pins so im guessing the ground was ok as this was the same as a you tube video i watched ha the haynes manual says charging coil resistance is 0.18-0.20 ohms so im guessing by this shes died as mines 0.00ohms just hope i havent frazzled my new reg/rec!

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thanks it does look that way i just hope the reg/rec isnt buggered the manual says typical faulty reg/rec symptoms are blowing bulbs, battery over heating. im not getting this so hopefully this is so as i have no idea on how to test it other than taking it in a garage for a test

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got the farther in law to test my reg/rec and all is good with that few! got the alternator out and it has bare wire showing :shock: no increase in voltage when taken to 5,000 revs too so looks like the verdicts in! second hand one coming for £38 so not too bad. from lings a new one £450! maybe its made of gold :lol:

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well still no where fast. ive learnt how to test cables for continuity anyhow :D i checked alternator wires,battery leads,fuse boxs and all its leads,reg/rec leads,earth leads all good. recharged battery thats good. put second hand alternator in but still no increase to 14v at5,000 revs?? think im missing something only thing i cant work out is how to test the alternator properly ive looked at vids lol. heres what i do:

ohms check should be 0.18-0.20 i have heard some multimeters will show 0.00 instead. im not sure where to put leads on this test i put multimeter to 2k on ohms and put negative lead to battery neg then positive to one of the 3 yellow alternator wire ends but i get 0.00????


voltage check:


ive heard voltage whilst running or revving should be high 20-40v on some bikes before it goes through to the reg/rec. im getting around 6v per yellow cable is this wrong? am i doing it wrong? could it be something else other than alternator?

bike does start up and runs but slowly gets lower and lower as day goes by. last time it was idling at 14,000 morning then afternoon 12.8 by morning 12,5.


when i rev it volts on battery reading go down slightly then releasing it shows a slight increase first time round after starting

then if i do it again no increase when revving or after releasing throttle. well lost with this one, im going to a mates whos an electrician tomorrow but after this who knows lol. maybe i bought a dead second hand alternator???

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OK mate......disconnect the battery. Then put the meter on it's lowest Ohms setting across 2 of the yellow wires from the alternator.....you should get approx 0.5 ohms....then check across another pair of the wires from the stator.....you should get the same reading......and do this until you've checked each combination of Stator wire pairs.

Then check the resistance on the Highest Ohms setting between each of the stator wires and the frame or engine......all 3 wires should show open circuit with respect to the frame. If all this checks out OK then the Stator should be OK.

Unplug the Stator from the Reg/Rec and start the engine......measure AC volts across the pairs of (yellow) wires coming from the Stator....you should see approx 30-50v AC across each pair of stator wires when the engine is revved.

If all this checks out OK....then it's likely that your Reg/Rec is stuffed..... :wink:

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Thanks for all your help once again! ! On the second part where I put negative to the frame then positive on each yellow stator wire for open circuit would that read 1 if ok? Sorry to sound daft just learnt how to test for continuity on a wire ha im trying to catch up with electrics!

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The displayed reading on the meter will vary according to the make of meter....... :?

Would it be possible to take a pic of the meter when connected? The other thing is when the meter is switched to M ohms setting look at the screen reading with the leads not attached to anything and not shorted together.....that is pretty much what you should see when the meter is connected between each of the stator wires and the engine casings. Make sure the reg/rec is disconnected when you do this so it doesn't have an influence. ........ :wink:

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firstly heres my old alternator and you can see the bare wire which i thought concluded it must have been this!

http://i1328.photobucket.com/albums/w526/glenbob2/2f83f3c6-7e44-46a0-accd-cbd16657efd6_zps83b9b896.jpg


here is a pic of me testing the ohms reading which according to my manual should be 0.18-0.20. I have heard some multimeter wont read such a small resistance so not sure how conclusive this is.Please ignore the connector blocks for the wires i was getting a flaky continuity on one of the pins so i decided for now to take it off and when sorted ill get a new block.

http://i1328.photobucket.com/albums/w526/glenbob2/20130906_081958_zps83e88c94.jpg


here is the reading before i test the ground on the 3 yellow wires (1) so the test should show 1 on each wire.

http://i1328.photobucket.com/albums/w526/glenbob2/20130906_082159_zpse7c26d29.jpg



indeed it does

http://i1328.photobucket.com/albums/w526/glenbob2/20130906_082309_zps6a72965b.jpg


im waiting for the rain to stop lol then im doing the other test and also ill try to upload a video link of the bike idling then at 5,000 so you can see what i mean. thanks again!!!

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Looking at that picture logically I don't think the wire wore away and damaged, that looks like it had a full on melt down on that part.


Go to here:


http://www.electrexworld.co.uk/cgi-bin/ ... 3aG54#aG54


I fitted one on a blown up Hornet once, when me and the chap rebuilt it ground up. High quality stuff.


Fit it with a new reg/rec, unless you have one already and check all wiring, fire it up and I bet it works :thumb:

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videos taking a long time to upload but while im waiting i got no voltage on the alternator so im guessing its that. its weird because as you will see on the video the battery is 12.5v bike off, ignition on 12.5v and going down, bike running it goes to around 13.5v so must be some voltage there. however no increase on throttle.

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i bought a second hand one that was supposed to be working (alternator) but doesnt look so. i took the end of though because of a flakey continuity test so i cant return the bloody thing. ive seen a new one on wemoto for £75. ive already got 2 reg/rec now lol.

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videos taking a long time to upload but while im waiting i got no voltage on the alternator so im guessing its that. its weird because as you will see on the video the battery is 12.5v bike off, ignition on 12.5v and going down, bike running it goes to around 13.5v so must be some voltage there. however no increase on throttle.

TBH that sounds OK..... 8-)

12.5 volts with engine off.......13.5v with it running......the Reg/Rec will stop the voltage going too high and cooking the battery..... :wink:

I'd run with that for a bit and see how it goes mate..... 8-)

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I think I will before spending any more. As long as no harm can be done ill just have to do a check on the system evrry fortnight or so. Thanks for all the help again if I ever see you about I owe you a drink or two:grin:

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