Non charging issues

[mark.read3]

if you've got a gt500 have you tried swapping a few bits over, like rectifier ?

[canaletto5]

Status update!
I have just done Bills test and I'm getting no reading from the multimeter whatsoever

Switch it on ?

Now I know I'm thick but the meter is definitely turned on
Thanks Kev, I'll nip out and try that now

I've measured the resistance between the slip rings (The excitation resistor) and it is about 5 ohms. I did this by placing one probe on each slip ring. See if yours is the same or close to. If it is open circuit (infinity) then there could be a problem with the stator.

[PaulD738]

Hi Kev, I've just come back in from the garage unfortunately in my haste I missed your latest check so that one will have to wait until tomorow. However the continuity check revealed that I was getting a circuit from the green wire terminal to the slip ring that brush runs on and the same from the terminal off the other brush to its slip ring is also buzzing out, however I noticed the green wire terminal/brush also buzzes out to earth (the engine case)? is this right?

[PaulD738]

if you've got a gt500 have you tried swapping a few bits over, like rectifier ?

That is something I never thought of and will try, unfortunately the 500 is garaged at a friends house 40miles away

[canaletto5]

Hi Kev, I've just come back in from the garage unfortunately in my haste I missed your latest check so that one will have to wait until tomorow. However the continuity check revealed that I was getting a circuit from the green wire terminal to the slip ring that brush runs on and the same from the terminal off the other brush to its slip ring is also buzzing out, however I noticed the green wire terminal/brush also buzzes out to earth (the engine case)? is this right?

It is picking up the earth through the excitation resistor so the reading should be about 5 ohms as well. This will be low enough for your buzzer to sound. It looks as though the brushes are contacting properly. If the green terminal is at zero ohms then it is shorting to earth somewhere which will cause a problem, Kev

[Oldbeancanopener]

Kev....erm yes I'm sure this is right. Please read my post fully. That's why I asked Paul to disconnect the voltage regulator and thus isolatie the green wire. By placing the meter between the battery live and the disconnected green terminal you have placed the meter in series.... The perfect place to read current or amps. . Have you forgotten to take your tablets

Regards

Bill

[Oldbeancanopener]

Hi Kev, I've just come back in from the garage unfortunately in my haste I missed your latest check so that one will have to wait until tomorow. However the continuity check revealed that I was getting a circuit from the green wire terminal to the slip ring that brush runs on and the same from the terminal off the other brush to its slip ring is also buzzing out, however I noticed the green wire terminal/brush also buzzes out to earth (the engine case)? is this right?

It is picking up the earth through the excitation resistor so the reading should be about 5 ohms as well. This will be low enough for your buzzer to sound. It looks as though the brushes are contacting properly. If the green terminal is at zero ohms then it is shorting to earth somewhere which will cause a problem, Kev

Kevin. This is just plain wrong. There is only one component resistor associated with excitation. This is located in the regulator. For current to travel to earth through this, DC would need to travel backwards. As Scottie would say "you cannot defy the laws of physics".

You also need to consider that Paul has already confirmed a voltage of 11.7V at the green terminal.

You would not get this reading if it was shorting to earth and a fuse would probably have blown.

Hope this helps

Bill

[Oldbeancanopener]

Paul

Sorry about all the confusion. This always happens when you get differing opinions. However, going back to a logical approach.....

The result of the test I suggested indicates that there is no current passing through the rotor

We already know that electricity is available at the green terminal because you measured 11.7 volts there

It also seems likely that your brushes are connecting to the slip rings correctly as your meter tests have indicated.

The next test is this. Remove the brushes from the slip rings and then with your meter set to ohms put one probe on each slip ring. You should read about 4 ohms. If there is no reading or very high resistance then your rotor is suspect

Regards. Bill

[canaletto5]

Always happy to learn Bill What is the purpose of the coil shown on the wiring diagram which appears to be physically located in the alternator and connects between the green terminal and earth. ? Kev

[Oldbeancanopener]

That's the rotor coil. It is the windings between the slip rings. It is not a resistor although it has some resistance. 4 ohms is quoted in the manual. Technically it is an inductor.

Hope this helps

Paul, here's a tip. Instead of removing the brushes, slip a piece of card between the brushes and the slip rings. This will isolate the slip rings so that you can do your test. Actually the published resistance is 10 ohms in the very early manual but let us know what you find.

With the brushes isolated there should be no continuity between either slip ring and earth

Regards

Bill