Rewound Alternator Rotor gouges, trouble shooting charging system.

[75XSFLORIDA]

Yes, you can mount it anywhere. It has a black ground wire running to it's inside, you just can't see where it goes because it's a totally enclosed unit. You see it on your original because it's an open air unit.

Measuring the resistance in the rectifier now…see pics. Am i at the right setting on my meter?? 200 ohms? To do this test

 

[Jan_P]

Taking the brushes out and the brown bracket that holds them in place…plenty of surface area to measure with all that out as im sure youre aware

So if I get this right the battery is OK
And the brushes is out
Rotor resistance OK . ??

Please measure the Voltage from the disconnected wires from each one and to Ground paying attention they are not in contact with any metal shorting.

And please report here --- .If .this is already done i Apologize.

 

[Jan_P]

Measuring the resistance in the rectifier now…see pics. Am i at the right setting on my meter?? 200 ohms? To do this test

Looks right if you switch the probes what is it reading

 

[75XSFLORIDA]

No, it just means it's weak. Low power from the regulator can cause it, weak battery... wore out brushes can cause it, a bad ground can cause it... as well as the rotor. Best thing to do is ohm the rotor and see if it's about 5 ohms between rings and open ring to case. If it is, the rotor's good and you'll need to look elsewhere.
Process of elimination.

Whats the best thing to clean the rotor rings with so they are bright and beautiful again?? With rotor still on bike though…not taking off

 

[gggGary]

Your VOM has a diode setting that's what a rectifier is 6 diodes.
Use that setting.


A how to test using the diode function;
Testing just a rectifier is done the same way as testing a regulator rectifier.

 

[75XSFLORIDA]

Your VOM has a diode setting that's what a rectifier is 6 diodes.
Use that setting.

View attachment 237669
A how to test using the diode function;
Testing just a rectifier is done the same way as testing a regulator recifier.

So doing it on any other setting than that I will not get accurate readings??

 

[gggGary]

You can do ANYTHING you want.
Since your tester has a diode setting, using that to test diodes would seem, well logical.

 

[75XSFLORIDA]

You can do ANYTHING you want.
Since your tester has a diode setting, using that to test diodes would seem, well logical.

So heres my findings….
The black wire when touching the black probe to it and the red proble to each white wire shows OL on each white wire, (assuming open circuit). …..when reversing, shows same thing, OL….however black probe to red wire shows about 500 on each white wire. When reversed shows OL.
THOUGHTS?

 

[gggGary]

I think you have located the, or at least a, problem area.
Since it's unlikely all three diodes failed at the same time, they're pretty tough little guys. (you didn't weld on the frame recently?) my guess is there is a bad ground connection somewhere in there.
But that doesn't matter much the fast and again IMHO BEST solution is a new rectifier.
Pretty much any 3 phase rectifier capable of say 30 amps of load should be fine.
The local electronics store might even have one.
There's piles of them on flea-Bay and Amazon.
This one would work fine.

https://www.amazon.com/Diode-Bridge...pY2tSZWRpcmVjdCZkb05vdExvZ0NsaWNrPXRydWU&th=1

 

[5twins]

I use a little chrome polish, then wipe the polish residue off with some electrical cleaner. The first pic shows just one ring cleaned, second shows both .....

 

[5twins]

My personal preference is an automotive regulator and a new modern rectifier of some sort. I like the $10 Windy Nation rectifier Jim and I have shown at the beginning of this thread. I don't care for those combined reg/rec units. Most are expensive and many are of poor quality and junk right out of the box (they don't work, lol).

 

[Jan_P]

So heres my findings….
The black wire when touching the black probe to it and the red proble to each white wire shows OL on each white wire, (assuming open circuit). …..when reversing, shows same thing, OL….however black probe to red wire shows about 500 on each white wire. When reversed shows OL.
THOUGHTS?

Skeptical
OK assuming this is correct it may happen -another day another lesson learned ? 6 Diodes fried ?? ..BUT I cannot see how this lead to a weak slap test on the alternator

 

[75XSFLORIDA]

I think you have located the, or at least a, problem area.
Since it's unlikely all three diodes failed at the same time, they're pretty tough little guys. (you didn't weld on the frame recently?) my guess is there is a bad ground connection somewhere in there.
But that doesn't matter much the fast and again IMHO BEST solution is a new rectifier.
Pretty much any 3 phase rectifier capable of say 30 amps of load should be fine.
The local electronics store might even have one.
There's piles of them on flea-Bay and Amazon.
This one would work fine.
View attachment 237670
https://www.amazon.com/Diode-Bridge-Rectifier-SQL100A-1600V/dp/B07GZQPZ74/ref=sr_1_2_sspa?crid=3H81I7UY35DYQ&keywords=3+phase+rectifier+12v&qid=1678761054&sprefix=3+phase+rectifier,aps,127&sr=8-2-spons&smid=A28ZWXW3ZSVNZU&spLa=ZW5jcnlwdGVkUXVhbGlmaWVyPUExVFgyN0FTODQwSVdFJmVuY3J5cHRlZElkPUEwMjgzNTYzM0tZUzhUOU9aVjIxMiZlbmNyeXB0ZWRBZElkPUEwNTE5MjYyMVJKN0xKRTYwUkJVNyZ3aWRnZXROYW1lPXNwX2F0ZiZhY3Rpb249Y2xpY2tSZWRpcmVjdCZkb05vdExvZ0NsaWNrPXRydWU&th=1

No I have not welded on the frame anything. He said there’s a bad ground somewhere perhaps. Am I supposed to be testing this when it is bolted on underneath the battery tray of the bike?? Because I am testing this OFF the bike and when it’s off the bike there really is no ground attached anywhere.

 

[75XSFLORIDA]

No I have not welded on the frame anything. He said there’s a bad ground somewhere perhaps. Am I supposed to be testing this when it is bolted on underneath the battery tray of the bike?? Because I am testing this OFF the bike and when it’s off the bike there really is no ground attached anywhere.

This amazon one that you provided the link for, how will i know what color wire out of the main bike harness attaches to each on the recitifier?? Unless the wires can attach anywhere

 

[jpdevol]

The rectifier is supposed to be tested unplugged from the harness. It is a bit unusual to find all 6 diodes failed - barring catastrophic event - but bad tests include solder joints and wires breaking too.

So the function of the rectifier is to limit current flow in only one direction. Most Ohmmeters flow current from red probe to black probe. So we're looking for current to flow from rectifier white to rectifier red (small ohm reading), but not r. white to r. black (OL). There's more to it, but that's a start....

 

[75XSFLORIDA]

The rectifier is supposed to be tested unplugged from the harness. It is a bit unusual to find all 6 diodes failed - barring catastrophic event - but bad tests include solder joints and wires breaking too.

So the function of the rectifier is to limit current flow in only one direction. Most Ohmmeters flow current from red probe to black probe. So we're looking for current to flow from rectifier white to rectifier red (small ohm reading), but not r. white to r. black (OL). There's more to it, but that's a start....

I know. Very strange but I definitely did the test correct

 

[75XSFLORIDA]

Different thread; you're conversing in two threads. But, once in hand, folks here can walk ya through it

Haha. Still rectifier related though

 

[gggGary]

@75XSFLORIDA
I think I know why your tests show THREE bad diodes. You DID say you're not an electrician.
If you are using the black wire in the connector as your test point; it's going NOWHERE. The other end is that crimp on connector sitting in air in the pic. Either bolt it to the rectifier chassis with the mounting bolt or put your probe on the chassis (chunk of metal the bolt goes into) to check the diodes.

 

[75XSFLORIDA]

Exactly! I was thinking the same thing. Its going into the air. Lol

 

[gggGary]

Yes wandering around posting about ONE system issue in multiple threads is not conductive to cogent answers.
He was getting THREE failed diodes not six but the problem was obvious once you looked at HIS pic in the other thread.

The black spade inside the connector was going nowhere, he had it unbolted from the rectifier chassis.
Patting myself on the back about doubting THREE diodes went bad at the same time.....