Alternator stroke charging problem

MJ24

MJ24

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West Wales
www.markjohnsonafloat.org.uk
I posted a thread about my alternator a while ago.

The alternator needs full revs to start charging. But after a few (10 to 20) seconds it stops charging again.

I had this alternator fitted about 4 years ago. I am pretty certain it is not marinised thus it's failure.

You kindly replied mentioning slip rings. Assuming this is the problem, how difficult is it to clean or oil these rings in order to allow charging to take place??

Or do I just replace the alternator every four years?.

Also I believe there are two genders of alternators, I need to get the voice to one as I gave an Adverc charge booster. How do I tell if it's a he or she or otherwise?

I am super the corrosion problem is because of under use, only 40 nm on the clock in 2013. Been a difficult year family wise!!!

TIA

MJ
 
I don't know about "genders", and I think the days of positive earth are long gone. The two types you refer to could be isolated and non-isolated. If the case is connected to the negative terminal, it isn't isolated. This can be a bad thing on a boat, depending on how or if your underwater gear is bonded.
 
Full revs to start charging is often due to too small a 'charging light' bulb.
The current through that initiates the regulator current.
Or could be dodgy brushes.
 
MJ24 said:
I posted a thread about my alternator a while ago.

The alternator needs full revs to start charging. But after a few (10 to 20) seconds it stops charging again.

I had this alternator fitted about 4 years ago. I am pretty certain it is not marinised thus it's failure.

You kindly replied mentioning slip rings. Assuming this is the problem, how difficult is it to clean or oil these rings in order to allow charging to take place??

Or do I just replace the alternator every four years?.

Also I believe there are two genders of alternators, I need to get the voice to one as I gave an Adverc charge booster. How do I tell if it's a he or she or otherwise?

I am super the corrosion problem is because of under use, only 40 nm on the clock in 2013. Been a difficult year family wise!!!

TIA

MJ
Click to expand...


No idea if the brushes and slip rings are your problem. Id have thought probably not but there is a big variation in the detail of alternator design but generally one would expect to be able to remove the end plate to access them. You dont say what make and model the alternator is, you dont even say what engine you have.
If you are the sort of person who can take things apart figure out how they should work, fix them and put them back together have ago. The slip rings should be clean and bright but not oiled.

OTHERWISE take it to an automotive electrician to sort out. probably cost £80 or there abouts.

BUT first check all the connections.

What does the warning light do at every stage of the game.

Dont know what you mean by gender but they can be either positive or negative regulated. IIRC this has to be specified if ordering an Adverc.

Isolated or non isolated is another variation as Nigel points out ........ dont think it matters as far as the adverc is concerned
 
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When talking external add on regulators alternators come wioth the regulation at battery side or ground side of field coils. An alternator takes current from the battery (and once running from a generated source in the alternator. This current can go first to the field coil via slip rings then through a regulator to ground (-ve) to control (limit) the current in the field coil. Or it can go to the regulator then the filed coil then to ground. The field coil current and hence magnetic field (the rotating part on an alternator) in being varied varies the output voltage of the alternator. So in normal operation there is no difference in whether the current is regulated before or after the field coil. But if you want to disconnect the internal regulator and substitute an Adverc you need anAdverc to suit the alternator type. (this may be what you mean by gender)
Regarding the slip rings. Often the internal regulator is a small box on the back of the alternator with typically 2 screws holding it on. If you remove the screws the box will come off with brushes attached. Depending on access it may be easier to do this with alternator removed. Through the hole thus exposed you will see the slip rings. They can be cleaned witha fine wet and dry sandpaper or similar. They are enot lubricated. The brushes can be examined for length. They do wear. When you refit the brushes you need to assess if there is enough spring pressure of the brushes on the slip ring. It is hard to describe how much pressure perhaps 5 or 10 grams. ie positive but not exceessive.
A spray with a WD spray or similar might keep corrosion at bay. Silicon grease on terminals will also help. Bearings should be sealed so no greasing needed but it should tuen easily with no noise.
good luck olewill
 
Thanks for all of your input. I will take the alternator to a local electrical shop that does the biz.

Might try a squirt of WD40 first. Just hope nothing catches fire.

Yes the gender reference was about the earthing. I know the original alternator was the opposite to what I have now.

Thanks again.....

Mj
 
I had a similar problem with charging a few years ago, on my Volvo V6 205 petrol, which is in fact a Ford pick up truck engine...USA
I took the Alternator to my local Lucas Service department who basically told me it was beyond repair... Volvo alternators at the time were £160.
On the shelf at Lucas a car replacement,Identical externally, apart from the end pulley, was £70...
Guess what.. I bought the cheaper, changed the pulley for the one off mine, and invested £2 50 on a small warning light that I wired in to show if it was charging, cable tied to the mounting bracket, and it was still charging the batteries 4 years on....
I gave it a good coat of Duck Oil now and again, Looked good as a 4 year Alternator was going to look when I sold the boat..
I believe it is still going 3 years on...
 
Today I removed the alternator and took it to an electrical shop.

Whilst they tried to sell me a new one, I think the problem is mainly the brushes. One of the two brushes is stuck and it's spring won't push it out onto the spindle (?)

So the shop is going to clean up the body and replace the regulator and brushes. I can see where the Adverc wire was soldered to, so will be able to redo that.

Whilst the problem was the brushes, I am concerned about corrosion. The body go the alternator is either steel or Ali, which can corrode a bit, but assume most of the workings are copper. My plan is to try and keep the engine compartment drier (wales and rain) or maybe vent the compartment to try and keep corrosion down to a minimum. The duck oil sound a good idea, assume WD40 is much the same.

Anyway, I have learnt a lot, and thanks to all for your wisdom.

MJ
 
As a very final comment on this thread, I have just collected my alternator from Shorts Electrical in Swansea.
For the princely sum of £44, they have renewed the regulator and cleaned and painted the alternator housing. (Battleship grey!)

It looks like new, and looks much better than it was when new.

Thanks to Shorts........
 
I suggest you keep WD40 and the like well away from your alternator. As others have said the slip rings must be dry and clean, as must the brushes that bear on them. The bearings will be oiled for life and sealed.
 
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