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-   -   Cruising Without Alternator (Temporarily) (https://www.cruisersforum.com/forums/f14/cruising-without-alternator-temporarily-219123.html)

theway 07-06-2019 19:10

Re: Cruising Without Alternator (Temporarily)
 
Quote:

Originally Posted by Stu Jackson (Post 2904399)
Pretty much, but what wotname and a64 said. It could be simple and usually the harder to fix parts are the parts that thankfully usually don't fail.


Again, another analogy: you're asking the doctor what's wrong before he even begins the examination.


Do you have Calder's Boatowners Manual? Good description of what goes on inside. You could probably find the same info by doing a Google on "How do alternators work?" wikipedia could help too, and I'll bet there are YouTube videos on alternator repair.


While you may learn how to do it, theoretically via la internet, in your case, and in my own personal experience, I'd have "the pros" do it. Not really something I'd think you'd want to learn right now. But some folks choose to do so and I applaud them for that.


Just my impression from this thread and discussions that you, personally, would be wise to have them do it. Heck, they even might let you look over their shoulder while they do it. My alternator repair shop back in California, Oakland your old stomping grounds!!!:), taught me a lot although I wasn't there when they cracked my case.


Good luck happy learning.:peace:



Cool, that all makes sense and yeah I carry the same sentiment - Let someone else do it and hopefully theyíll let me watch. And after watching enough times maybe attempt, but only with a pro nearby to help if need be.

I do have the Calder book and plan to study it more before I go.

And thanks again all, Iíll update as things progress. Removal tomorrow and up to Mataram on Monday.

Rumpi 07-06-2019 22:14

Re: Cruising Without Alternator (Temporarily)
 
Quote:

Originally Posted by wingssail (Post 2904157)
How do we know it is brushes? Could it not be a field winding failure?

Yes it could, but logic says to first supect the part that moves and wears out. Without smoke escaping one usually does not suspect the windings beforehand, but they get tested anyway when the case is open. I am curious to hear what it was after all.

Theway the one thing to watch out when rebuilding is the bearings. Now if they need replacing or you want to do it anyway be sure to buy some where you recognize the brand.
Basicly there are 3 steps: repair, refurbish, remanufacture. Repair means restoring function. Refurbish usually means renew all wear parts. Remanufacture means bringing everything back to factory spec, including the paint. An alternator is such a simple machine that repair and refurbish is hard to distinguish.

Wotname 07-06-2019 22:43

Re: Cruising Without Alternator (Temporarily)
 
Quote:

Originally Posted by Rumpi (Post 2904480)
Yes it could, but logic says to first supect the part that moves and wears out. Without smoke escaping one usually does not suspect the windings beforehand, but they get tested anyway when the case is open. I am curious to hear what it was after all.
..................

Exactly :thumb::thumb:

Alternator brushes last a very long time (usually many thousand hours) and field windings outlast brushes by several orders of magnitude. They usually only fail due to abuse (high loads and compromised cooling).

At least that has been my experience - YMMV!

masonc 08-06-2019 03:55

Re: Cruising Without Alternator (Temporarily)
 
Isn it externally regulated or internally?

Rumpi 08-06-2019 04:13

Re: Cruising Without Alternator (Temporarily)
 
Externally regulated but with internal rectification. Probable identification as Balmar series 9.

Theway, can you take some photos once it is out?

masonc 08-06-2019 07:07

Re: Cruising Without Alternator (Temporarily)
 
Has he tried exciting it

theway 10-06-2019 08:06

Re: Cruising Without Alternator (Temporarily)
 
I got the alternator off and had it looked at. He showed me the brushes and indicated that was the problem (they looked really short/worn).

I watched him go through a serious of tests with the meter connecting all different bits and seeing the needle jump. 20 minutes after he started it was done.

Now the question, Could the brushes be a reason I wasnít getting magnetism? Or is there something else I should have him test/look at?

(Iíll post some pics soon)

Rumpi 10-06-2019 09:40

Re: Cruising Without Alternator (Temporarily)
 
The brushes carry the current from the voltage regulator to the rotor winding via the sliprings. If the brushes are stuck or worn there is no contact between brush and slipring, and no current reaches the rotor coil. No current = no magnetic field = no output. Solution is to replace the brushes. So has he replaced the brushes and is the alternator working?

I supose he did all the usual tests and found everything ok or he would have pointed at the defect and waved his hands and head in dismay. Beside worn brushes the other common defect is grooved sliprings.

theway 10-06-2019 10:19

Cruising Without Alternator (Temporarily)
 
Quote:

Originally Posted by Rumpi (Post 2905909)
The brushes carry the current from the voltage regulator to the rotor winding via the sliprings. If the brushes are stuck or worn there is no contact between brush and slipring, and no current reaches the rotor coil. No current = no magnetic field = no output. Solution is to replace the brushes. So has he replaced the brushes and is the alternator working?

I supose he did all the usual tests and found everything ok or he would have pointed at the defect and waved his hands and head in dismay. Beside worn brushes the other common defect is grooved sliprings.



Hey Rumpi... yup, he showed me the brushes and i could see how short they were, I gave the nod to fix and they were replaced. And yup he did a few test, one test he did a little out of my sight with a battery on the floor, guessing that might have tested magnetism... after that he gave the nod that it was good.

Thanks for the explanation, I was googling but nowhere explains that link between brushes and magnetism.

Iíll be a couple nights here in Mataram and then Iíll install Thursday or Friday.

theway 10-06-2019 10:39

Re: Cruising Without Alternator (Temporarily)
 
3 Attachment(s)
Hereís some photos.

Before and after I cleaned it. As I mentioned I had an exhaust leak last year. Iíve cleaned up most things....

Model plate...

And some pics from the shop... Looks pretty old, but he didnít call attention to anything but the brushes.

Attachment 193661
Attachment 193663

Attachment 193662

lateral 10-06-2019 13:29

Re: Cruising Without Alternator (Temporarily)
 
If you want a cheap drop in high amp spare alt that will fit a 3GM30f a bosch from a 944 porsche will fit if you grind a couple of mm of the rear foot and pack with acouple of washers on the front. Two min job.
Has the advantage of being able to swap out brushes in 5mins as there external and being able to externally regulate as the brush set and regulator are one piece. Non regulated brush sets are available.
ALSO comes with a cowl to supply external cool air.
MUST use gates green stripe belts if single.
$50-100 on ebay.
Pm me if anyone wants details.
https://www.ebay.com/itm/PORSCHE-944...MAAOSweX5cKBAn

I did fab up a custom tensioner as the hitachi one wont fit.

RaymondR 10-06-2019 13:32

Re: Cruising Without Alternator (Temporarily)
 
Easily detected fault with a simple test.

Like most of us I did not know a lot about alternators before I took up boating in remote places. I have the alternator subject pretty well covered now and am working on refrigeration.

theway 10-06-2019 21:42

Re: Cruising Without Alternator (Temporarily)
 
Quote:

Originally Posted by Rumpi (Post 2902595)
I have to point out the obvious: alternators don't die from sitting around. If it was fine 4 months ago it's fine now. Your problem is corrosion.

Can we back up to this for the sake of exploitation? Because this still seems like one of the most notable and valuable points. If I reinstall the alternator and everything is fine, and the problem was fixed by new brushes... How does that explain why it worked 4 months ago and not now?

Any guesses or logical conclusions based on experience?

(The engine wasnít running and the brushes wouldnít just wear themselves down)

Fore and Aft 10-06-2019 22:42

Re: Cruising Without Alternator (Temporarily)
 
Off subject a little bit but I had a 40 amp Victron battery charger mounted near my Smokey generator. One day it stopped working when I opened it up it was covered in carbon from the exhaust. I blew it down then cleaned it with WD40, moved its location and it has worked fine ever since.
Cheers

RaymondR 11-06-2019 00:23

Re: Cruising Without Alternator (Temporarily)
 
Quote:

Originally Posted by theway (Post 2906306)
Can we back up to this for the sake of exploitation? Because this still seems like one of the most notable and valuable points. If I reinstall the alternator and everything is fine, and the problem was fixed by new brushes... How does that explain why it worked 4 months ago and not now?

Any guesses or logical conclusions based on experience?

(The engine wasnít running and the brushes wouldnít just wear themselves down)

Worn brushes causing little spring force allowed brushes to become stuck in the brush holders.


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