Alternator regulator operation - SailNet Community

   Search Sailnet:

 forums  store  


Quick Menu
Forums           
Articles          
Galleries        
Boat Reviews  
Classifieds     
Search SailNet 
Boat Search (new)

Shop the
SailNet Store
Anchor Locker
Boatbuilding & Repair
Charts
Clothing
Electrical
Electronics
Engine
Hatches and Portlights
Interior And Galley
Maintenance
Marine Electronics
Navigation
Other Items
Plumbing and Pumps
Rigging
Safety
Sailing Hardware
Trailer & Watersports
Clearance Items

Advertise Here






Go Back   SailNet Community > On Board > Gear & Maintenance
 Not a Member? 
  #1  
Old 08-03-2008
Sea Slacker
 
Join Date: Jan 2007
Posts: 1,789
Thanks: 0
Thanked 0 Times in 0 Posts
Rep Power: 8
brak is on a distinguished road
Alternator regulator operation

Today during sail (motoring, really) I realized that my alternator is not charging - it was barely putting out 12.8V.

I have an external regulator from Xantrex, so I was able to adjust the ACCEPT voltage (this probably regulates "field" whatever it is). A few turns and it was charging again at 14.1V as the manual says it should.

Here is the thing though - it used to charge just fine with old settings (I didn't follow voltage closely but ACR always turned on when alternator was on, so it was definitely above ACR closing voltage which is 13.1V).

So, now I am wondering - what would cause this? Could there be something wrong with an alternator (which I just masked by adjusting the regulator?)?
Reply With Quote Quick reply to this message Share with Facebook
  #2  
Old 08-04-2008
erps's Avatar
the pointy end is the bow
 
Join Date: Aug 2006
Location: La Conner, Washington
Posts: 6,215
Thanks: 2
Thanked 26 Times in 26 Posts
Rep Power: 10
erps will become famous soon enough erps will become famous soon enough
I don't think your alternator is the problem. Typically, they either work, or don't work.

I would put a volt meter on your battery terminals and then the hot terminal on your alternator to independently confirm/verify that your other volt meter is giving you accurate information. It could be that everything is fine but for some reason your volt meter has a bad connection. If your voltmeter is accurate, I'd suspect a voltage regulator problem but continue to monitor the situation since your fix.
__________________
Ray
S.V. Nikko
1983 Fraser 41
La Conner, WA


To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.


Boating for over 25 years, some of them successfully.
Reply With Quote Quick reply to this message Share with Facebook
  #3  
Old 08-04-2008
Sea Slacker
 
Join Date: Jan 2007
Posts: 1,789
Thanks: 0
Thanked 0 Times in 0 Posts
Rep Power: 8
brak is on a distinguished road
Quote:
Originally Posted by erps View Post
I don't think your alternator is the problem. Typically, they either work, or don't work.

I would put a volt meter on your battery terminals and then the hot terminal on your alternator to independently confirm/verify that your other volt meter is giving you accurate information. It could be that everything is fine but for some reason your volt meter has a bad connection. If your voltmeter is accurate, I'd suspect a voltage regulator problem but continue to monitor the situation since your fix.

I used a main panel voltmeter and also a separate digital meter - so I am fairly certain the readings are correct. I guess regulators go bad too sometimes, this one is from PO (last electric device on the boat that I did not replace ) so it could be pretty old. Guess I'll keep watching this thing.
Reply With Quote Quick reply to this message Share with Facebook
  #4  
Old 08-04-2008
erps's Avatar
the pointy end is the bow
 
Join Date: Aug 2006
Location: La Conner, Washington
Posts: 6,215
Thanks: 2
Thanked 26 Times in 26 Posts
Rep Power: 10
erps will become famous soon enough erps will become famous soon enough
It is pretty strange that something changed since the last time the engine ran. Could the adjusting screw you used to change the acceptance voltage have gradually moved over time?
__________________
Ray
S.V. Nikko
1983 Fraser 41
La Conner, WA


To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.


Boating for over 25 years, some of them successfully.
Reply With Quote Quick reply to this message Share with Facebook
  #5  
Old 08-04-2008
Sea Slacker
 
Join Date: Jan 2007
Posts: 1,789
Thanks: 0
Thanked 0 Times in 0 Posts
Rep Power: 8
brak is on a distinguished road
Quote:
Originally Posted by erps View Post
It is pretty strange that something changed since the last time the engine ran. Could the adjusting screw you used to change the acceptance voltage have gradually moved over time?

I thought about it but it looks extremely unlikely. It is one of those little adjustable parts (most likely a potentiometer of some sort) and I really don't see it moving on its own. Not impossible, but not my first explanation.
Reply With Quote Quick reply to this message Share with Facebook
  #6  
Old 08-04-2008
Senior Member
 
Join Date: May 2007
Posts: 551
Thanks: 3
Thanked 3 Times in 3 Posts
Rep Power: 8
SteveInMD is on a distinguished road
Could a dirty connection somewhere be adding resistance to the circuit?
Reply With Quote Quick reply to this message Share with Facebook
  #7  
Old 08-04-2008
Senior Member
 
Join Date: May 2007
Posts: 551
Thanks: 3
Thanked 3 Times in 3 Posts
Rep Power: 8
SteveInMD is on a distinguished road
You can jumper full voltage (like from he output post) straight to the field connection on the alternator. This basically bypasses the controller. The alternator should then crank out max output. That will tell you if the problem is the controller or the alternator. Obviously you don't want to leave it like this for a long time!

This is also a good trick to know if you regulator goes out while at sea. However, you do have manually control your charging so you don't ruin your batteries. You just full field the alternator until your voltage comes up to 14.4 or so then remove the field jumper for a while and repeat.
Reply With Quote Quick reply to this message Share with Facebook
  #8  
Old 08-04-2008
erps's Avatar
the pointy end is the bow
 
Join Date: Aug 2006
Location: La Conner, Washington
Posts: 6,215
Thanks: 2
Thanked 26 Times in 26 Posts
Rep Power: 10
erps will become famous soon enough erps will become famous soon enough
This problem kept me up last night. I first thought it was probably a connector between the regulator and the field terminal that had resistance in it. I thought the regulator would be sending out the right voltage to the field terminal but that it just wasn't getting there. But when Brak was able to overcome this with a manual adjustment, I start doubting that theory. So anyway, last night I considered that if continues to be "flaky" and give intermitent outputs, I would start to suspect that it's the slip ring brushes inside the alternator that are dirty or worn out. At any rate, I'll be interested to see what the real problem turns out to be.
__________________
Ray
S.V. Nikko
1983 Fraser 41
La Conner, WA


To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.


Boating for over 25 years, some of them successfully.
Reply With Quote Quick reply to this message Share with Facebook
  #9  
Old 08-04-2008
Sea Slacker
 
Join Date: Jan 2007
Posts: 1,789
Thanks: 0
Thanked 0 Times in 0 Posts
Rep Power: 8
brak is on a distinguished road
So dirty brushes would increase resistance? How can I check that - do I need to take the alternator off and open it up?

I am fairly sure it is not an external connector (as hard as it is to understand my engine's wiring harness - it was done by PO's mechanics when repowering and its one part of electric system I just don't get - lots of wires back and forth, all in one duck-tape-bound tube). Still, I am fairly sure I found the field connector and it looks just fine.

Quote:
Originally Posted by erps View Post
This problem kept me up last night. I first thought it was probably a connector between the regulator and the field terminal that had resistance in it. I thought the regulator would be sending out the right voltage to the field terminal but that it just wasn't getting there. But when Brak was able to overcome this with a manual adjustment, I start doubting that theory. So anyway, last night I considered that if continues to be "flaky" and give intermitent outputs, I would start to suspect that it's the slip ring brushes inside the alternator that are dirty or worn out. At any rate, I'll be interested to see what the real problem turns out to be.
Reply With Quote Quick reply to this message Share with Facebook
  #10  
Old 08-04-2008
erps's Avatar
the pointy end is the bow
 
Join Date: Aug 2006
Location: La Conner, Washington
Posts: 6,215
Thanks: 2
Thanked 26 Times in 26 Posts
Rep Power: 10
erps will become famous soon enough erps will become famous soon enough
IIRC, the voltage regulator controls the amount of current going to the spinning electro-magnet in the middle of the alternator. A stronger magnetic field induces more current to come out of the wire windings around the spinning protion. The electricity from the windings alternates back and forth from positive to negative as the north/south poles of the spinning electro-magnet spin pass them. The three wire windings pass through diodes. They act as an on/off switch and only allow the current to pass through only one way, either positive to negative, giving us D.C. current for our D.C. system.

If the brushes that make contact with the slip ring terminals to the electro-magnet are worn/dirty/weak springs, the regulator may be telling the electro magnet to produce a strong current, but it can't because it's not getting the voltage it needs. I recollect that you can check with this an ohm meter, but I don't remember how to do it off the top of my head. I had some alternator problems two years ago and found some detailed testing procedures online for checking the diodes. Without that, it would require splitting the case open and taking a look at the brushes. New brushes are typically .75 to .50 inches long. If they're getting down to .25 inches, I would suspect they're worn out.
__________________
Ray
S.V. Nikko
1983 Fraser 41
La Conner, WA


To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.


Boating for over 25 years, some of them successfully.
Reply With Quote Quick reply to this message Share with Facebook
Reply

Quick Reply
Message:
Options

By choosing to post the reply above you agree to the rules you agreed to when joining Sailnet.
Click Here to view those rules.

Register Now

In order to be able to post messages on the SailNet Community forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.
Please note: After entering 3 characters a list of Usernames already in use will appear and the list will disappear once a valid Username is entered.
User Name:
Password
Please enter a password for your user account. Note that passwords are case-sensitive.
Password:
Confirm Password:
Email Address
Please enter a valid email address for yourself.
Email Address:

Log-in

Human Verification

In order to verify that you are a human and not a spam bot, please enter the answer into the following box below based on the instructions contained in the graphic.




Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools

 
Posting Rules
You may post new threads
You may post replies
You may post attachments
You may edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is On



All times are GMT -4. The time now is 01:46 PM.

Add to My Yahoo!         
Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2014, vBulletin Solutions, Inc.
SEO by vBSEO 3.6.1
(c) Marine.com LLC 2000-2012

The SailNet.com store is owned and operated by a company independent of the SailNet.com forum. You are now leaving the SailNet forum. Click OK to continue or Cancel to return to the SailNet forum.