Alternator assembly ... or, when curiosity gets the better of me

[Scott T-Bird]

Thx for the reminder. What size alternator did you get/have? Is it a Hitachi? What size is your house bank? Just curious. Good luck, hope your alternator repair shop does you "good."

Previous owner replaced the stock Hitachi with this Powermax 125 amp alternator. He was original owner and I don't know exactly when he replaced it but it looks like it was quite a while ago. He told me that the original was horrible on belts and he didn't have any issues with belts once he replaced the alternator. He is an electrical engineer, for what that's worth. He installed the Balmar external regulator and I assume he programmed it based on his own thoughts and preferences. I hadn't planned on changing anything other than the pulley kit.

The boat came with 2 4D AGM Batts and a Grp 31 auxiliary batt, so bank is up to 400 ah depending how good they are. They were installed in 2015 so they have some age. Last season, no alarm bells anyway. He had the boat on a mooring with solar charging to keep them topped off at all times, which allowed him to run the fridge continuously. I disconnected the solar as the panels looked like they are in very rough shape and I'm on shore power so I didn't feel the need.

 

[Oksailor]

I use a piece of thread tie it around the holder to keep the brush in and then when you slip in the commutator, just snip the thread or string.
bingo!

 

[Maine Sail]

That’s a 10DN frame alternator. We build our AMP-IT HD125-ER on that frame witha lot of tweaks. I will post a photo in the morning of how easy it is to set the brush holder...

 

[Stu Jackson]

He installed the Balmar external regulator and I assume he programmed it based on his own thoughts and preferences. I hadn't planned on changing anything other than the pulley kit.

Which Balmar regulator? How come you're not going to change anything? Just figuring you'd want to at least know what it has been programmed to do. I'm sure you're aware Mainsail has a great How To Program on his site.

 

[Maine Sail]

This is one of our rear-ends ready for build. In order to reset the brushes you will need to pull the brush holder and find a long enough smooth metal "pin" that can hold them retracted while also protruding out the back of the alternator. When retracted for rotor install the brushes are deep into the brush holder, not flush with the white plastic.. The middle of the holder (blue arrow) retains the pin. Do not insert the pin beyond the inner edge of the brush holder. The stator tap arm nut needs to come off as well as have the two brush holder machine screws removed (red arrows) in order to pull the brush holder and re-set it. Once the brushes are held in place by the pin you can then re-install the brush holder. You can then put some high temp grease in the needle bearing and re-install the rotor. Take some denatured alcohol and clean the slip rings surfaces before you do this. Don't lose any washers..

 

[Scott T-Bird]

Which Balmar regulator? How come you're not going to change anything? Just figuring you'd want to at least know what it has been programmed to do. I'm sure you're aware Mainsail has a great How To Program on his site.

Yes, I was happy to see the article! Contrary to MS recommendation, this is mounted in the engine compartment about 8" from the mixing elbow. The elbow is entirely wrapped in insulation at least. I'm confused about the white wire being disconnected and something I'll need to find out about.

 

[Scott T-Bird]

This is one of our rear-ends ready for build. In order to reset the brushes you will need to pull the brush holder and find a long enough smooth metal "pin" that can hold them retracted while also protruding out the back of the alternator. When retracted for rotor install the brushes are deep into the brush holder, not flush with the white plastic.. The middle of the holder (blue arrow) retains the pin. Do not insert the pin beyond the inner edge of the brush holder. The stator tap arm nut needs to come off as well as have the two brush holder machine screws removed (red arrows) in order to pull the brush holder and re-set it. Once the brushes are held in place by the pin you can then re-install the brush holder. You can then put some high temp grease in the needle bearing and re-install the rotor. Take some denatured alcohol and clean the slip rings surfaces before you do this. Don't lose any washers..

Thanks! Perfect photo. Coincidentally, I was at job yesterday and worker found a pin on the ground right behind the bumper of my car. He picked it up & asked me if I was "missing this". No, but it looked like it might be the perfect tool for this job so I brought it home! I'll take a picture when I re-assemble it later tonight or tomorrow night. Thanks for the tip ... I'll clean the slip rings.

 

[Stu Jackson]

Contrary to MS recommendation, this is mounted in the engine compartment about 8" from the mixing elbow. The elbow is entirely wrapped in insulation at least. I'm confused about the white wire being disconnected and something I'll need to find out about.

1. Move it. Really. You have one of the best regulators out there. Regardless of the required insulation on the riser, it WILL get hot in the engine compartment, and will KILL your regulator. There is a REASON everyone recommends NOT putting it there.

2. My records show the white wire is for a tach. Who knows what the PO did with color coding. I know you'll track this down. These sketches might help you:

Alternator Regulator Wiring Diagrams - all three Alternator Regulator Wiring Diagrams (all three)

3. In addition to those sketches, the manual for your regulator shows what each of the plugs is for. The manual is available online at www.balmar.net if you don't have one.

4. Programming a Balmar External Voltage Regulator
Programming a Balmar External Voltage Regulator - Marine How To

Good luck.

 

[Ward H]

@Scott The white wire is part of the wiring harness that came with MC-614.
Here's the section from the manual talking about it.
"Install WHITE Stator-In And Tach-Out Wires
When an electric tachometer is used, the alternator’s stator output will provide the electrical pulse needed to drive the
tachometer. The MC-614 has been designed to provide regulated tach output when the WHITE stator wire is connected to theregulator’s Stator In (#12) terminal and the out feed wire to the electric tachometer is connected to the Tach Out t1e6rminal (#13)terminal. *Not required for magnetic pick-up Tachs.
Stator output can also be used to detect alternator failure. See Page 10 for details.
When the tachometer is connected via the MC-614, the regulator will ensure that the tachometer will not discontinue supplying field current when the batteries are fully charged. When connecting the tachometer to the alternator stator output, it will be necessary to determine the number of poles in the alternator in order to properly adjust
your tachometer. Most Balmar alternators feature 12-pole rotors and stators, though, in
some cases, the pole count may be 14. See alternator manual for specifics. See your
tachometer manual for adjustment instructions."

I can help checking the programing when you're ready.

Edit: Stu beat me to it.

 

[Stu Jackson]

@Ward H Could be Scott has a tach driven mechanically, not thru his alternator. Maybe that's why. Only he can tell us.

 

[Ward H]

@Stu Jackson That's my guess. Or the tach is connected to the stator post directly at the alternator.
That white wire has the unused spade connector on it that comes on all the wires in the harness so it was never used.

 

[Scott T-Bird]

Well, with a little help from my friends , I solved my problem! It's funny how things work out. I guess I could have used a paper clip or something else, but I found this pin behind my car at a work site. It was the perfect fit!

Fit the brushes, slipped in the pin and pulled it out the back side. I should be embarrassed that I didn't see the solution, but now I know!

 

[Scott T-Bird]

@Stu Jackson That's my guess. Or the tach is connected to the stator post directly at the alternator.
That white wire has the unused spade connector on it that comes on all the wires in the harness so it was never used.

Yes, the tach is mechanical, not driven by the alternator. Previous owner has plenty of notes and the manual for the regulator so I won't have to guess what he did.

 

[Ward H]

Joe, your PO, was the type of PO we all wished we bought our boats from.

 

[mermike]

View attachment 191099

That is some sweet engine access. (In the other attachment, not this one) Jealous. You would not believe what I have to do just to check the oil. Don't get me started on the lift pump.