Problem with green and red light

[stefano]

I've a problem with the Alternator/Regulator that don't charge batteries.
I've a 120A Amplepower Alternator + Next Step Regulator.

With the engine on at 1.500 rpm, I've checked the voltage on the alternator: I have 12,65 volts and on the Field I have oscillating 5,5-8,5 volts.
On the Alternator I have the green light 2 secs on + 1 sec off (maximum charge); the red light 1 sec on + 1 sec off (field always positive).

I also have the charge light on the engine panel flashing !!!!

I don't realize if the problem is on the Alternator or on the Regulator.

Thanks.

[Coulomb]

This could be an open circuit from the regulator to the alternator.

Have you done a full field test on the alternator?

[stefano]

Do you mean that there could be a cable between alternator and regulator that is broken ?

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How can I do a full field test on the alternator?

The test I've done is the following: I've connected, for a moment, the field connector on the alternator to the positive connector on the alternator, but nothing has changed.

Many thanks.

[Coulomb]

That indicates the alternator field is open. Maybe brushes worn out or open winding.

[stefano]

Bad news !!!
Do you think it is possible to repair it ?
Is it an expensive service ?
Thanks

[Coulomb]

Brushes are the most likely cause, which are quite inexpensive. Any one handy with tools can change them.

If it's the rotor, that gets to be expensive. It easy to change, but the part is costly. You need to measure the resistance of the rotor winding, between the slip rings.

[stefano]

Somebody told me about Diodes worn. Do you confirm ?

I'll send the Alternator to a local Service Center tomorrow.
Hope it will be repaired without big money !!!
Will let you know.

Thanks.

[Coulomb]

Diodes can fail, but usually there is just reduced output.

If the local alternator repair shop changes the rotor be careful to test for high output later. A standard rotor will not be able to produce full output.

[stefano]

Bad news !!!
Looks like the alternator is full of rust and cannot be refurbished.
I put a couple of pictures.
How can it be possible ?

[stefano]

Dear Coulomb, at this point I have a doubt.
With the alternator in this conditions, I'm not sure if the regulator could have been damaged.

Is there a test that I can do to verify if the regulator is still properly working ?

This will help me to make a decision about what to do.
Many thanks.

Stefano