Alternator and external regulator issue

[Jack Chapman]

Hi,

I am hoping someone can help me with an alternator conundrum. Apologies in advance, I have only a very rudimentary of electronics.

I am re-installing the alternator on my boat. I have just copied the wiring set up that existed previously. It seems to be working at least at a basic level since the battery voltage increases to over 14v when it is running. I have made a very childish wiring diagram in Paint to explain it.

The issue I have is that the field wire from the external regulator appears to live all the time. Including when the switched input (red wire, far right) to the regulator is turned off and when the engine isn't running. It is simply drawing power off the wire (the red one with the fuse) connecting to the battery post on the alternator. The issue is then that the current is just continually running out the ground at about 2.5A and draining the battery.

So I think this is not a problem with my alternator? (If I understand correctly, current ought to be able to flow relatively freely from the field connection to the ground in the alternator?)

But should the regulator not somehow switch the field wire off when not in operation?

It seems an easy fix would be to throw a switch into the circuit somewhere and just flick it on when I turn the engine on, but is this indicative of some other problem with the regulator or the wiring?

Thanks in advance for any assistance

Cheers

Jack

[nuku34]

More details would be helpful before suggesting a fix. What brand and model is your external regulator? Is the field of the alternator negative or positively controlled?

Just off the cuff though, something looks fishy if the external regulator has TWO positive inputs as per your sketch. There should be only ONE positive input and that should come from the ignition switch so the regulator only has power when the engine is on. The connection you show from alternator B+ post through the in-line fuse (which goes straight to the battery ad is "hot" all the time) is IMHO wrong.

Again, IMHO, this is not an alternator problem, but a problem with the wiring of the external regulator.

[Jack Chapman]

The external regulator is an Incharge Heart Interface. I have only found a half cut off wiring diagram from the manual online. I've also attached a picture pulled of the web. The input are not in the same order/positions as my original diagram: the +12v IN is the fused wire from the positive alternator terminal and the REG ON is the wire with the switch.

I've no idea what brand the alternator is. There isn't a bit of writing on it that I can find. I assume the field of the alternator is positively controlled based on the way it was wired...

[Jack Chapman]

For whatever reason the person that installed the regulator put the REG ON wire through a separate switch on the main electronics control panel rather than the ignition switch as you say. It is a bit odd, but I don't think it is a problem, I just have to remember to turn it on when I use the engine.

It would make sense to me if this was the control for the field output as you say, but it isn't currently the case. So is there maybe something wrong internally in the regulator?

[nuku34]

Whoever wired the regulator didn't do it correctly according to the manual. The regulator has a permanently wired "12vt In" which is connected to the battery through the fued line to the alternator "B+ post. That's correct. But the "Reg On" should have gone to the oil pressure sender on the engine, not a separate switch on the electrical panel. This is because it automates the process of the regulator being on when the engine is running, and off when its not. (The way its wired now you have to remember to turn the reg on every time you use the engine; what if you forget, then no charge to the battery, if you leave it on which the engine is not running, then you are putting current to the alternator field coil and draining the battery).


The person who wired the reg was probably lazy and didn't take time to find the oil pressure sender on the engine.

Alternatively, according to the manual, you could wire the reg on to the ignition switch so the reg is on only when the ignition switch is on.
As a test of the regulator, you need to turn off the regulator switch on your panel, temporarily disconnect the field wire from the regulator, put a voltmeter between that regulator terminal and any 12v ground. If there is voltage, then the regulator is faulty. The reg should not be passing field current when the "Reg ON" switch on your panel is off.

[smac999]

disconnect the field wire from the alt. measure if the 12v is on the alt field post or the reg wire. that will determine which side the issue is. the reg or the alt.

you should not have 12v on the field wire when the reg is off.

[jordanbigel]

Originally Posted by nuku34

Whoever wired the regulator didn't do it correctly according to the manual. The regulator has a permanently wired "12vt In" which is connected to the battery through the fued line to the alternator "B+ post. That's correct. But the "Reg On" should have gone to the oil pressure sender on the engine, not a separate switch on the electrical panel. This is because it automates the process of the regulator being on when the engine is running, and off when its not. (The way its wired now you have to remember to turn the reg on every time you use the engine; what if you forget, then no charge to the battery, if you leave it on which the engine is not running, then you are putting current to the alternator field coil and draining the battery).


The person who wired the reg was probably lazy and didn't take time to find the oil pressure sender on the engine.

Alternatively, according to the manual, you could wire the reg on to the ignition switch so the reg is on only when the ignition switch is on.
As a test of the regulator, you need to turn off the regulator switch on your panel, temporarily disconnect the field wire from the regulator, put a voltmeter between that regulator terminal and any 12v ground. If there is voltage, then the regulator is faulty. The reg should not be passing field current when the "Reg ON" switch on your panel is off.

I am not sure the installer did this by accident, or due to laziness. I think it is a way to manually control when the Alternator is working, for example, when you want to devote every KW of power to the drive shaft and not the alternator, I have heard (I don't do this) you can cut power to the regulator which shuts down the alternator. At least I have heard some people do this, and it seems deliberate to me.

[Jack Chapman]

Yes, the field wire (not from the alternator) has 12v even when the regulator is switched off. So the +12v IN wire seems to be connecting to the field wire somewhere inside the box. And if that is the case then I sort of doubt the regulator is doing any actual regulation of the field output at all.

I'll take a look under the cover when I go down to the boat today, but unless it is something easy, then it sounds like a need a new regulator.

[Jack Chapman]

Regarding the dedicated switch for the regulator. I also suspect it was a deliberate introduction. The control panel for the engine is right next to the regulator so it would have been easy enough to wire it the conventional way. Whoever wired the boat seems to have known what they were doing best I can tell, even when they made idiosyncratic choices. In any case it doesn't bother me now and it is easy enough fix that if I choose to.

[wsmurdoch]

Given that you have a Heart regulator, I'd suspect you have a modified 10DN General Motors alternator like this




or with the more usual fan

[Boatyarddog]

Originally Posted by Jack Chapman

The external regulator is an Incharge Heart Interface. I have only found a half cut off wiring diagram from the manual online. I've also attached a picture pulled of the web. The input are not in the same order/positions as my original diagram: the +12v IN is the fused wire from the positive alternator terminal and the REG ON is the wire with the switch.

I've no idea what brand the alternator is. There isn't a bit of writing on it that I can find. I assume the field of the alternator is positively controlled based on the way it was wired...

Having read the information on this charge unit.
You should not have an internally regulated alternator, but you didn't answer to that question.
I'm not sure your alt. Is compatable, with this unit.

https://www.cruisingequipment.com/pr...leshooting.pdf

Please read where N type alternators have to be modified, internally regulated models.
Alpha or Incharge units use a P type alternator.
This link has troubleshoot info, and is generally informative.
Also, there is a number listed to call for some real support.
Boatyarddog

[Jack Chapman]

I am quite sure that it is externally regulated. If I disconnect the field wire from the regulator with the alternator spinning I read 12+ volts at the battery, if I connect the field wire to the alternator I get 14+ volts at the battery. Seems pretty clear cut to me...?

I'm fairly sure the fault is with the regulator itself though and the fault seems to exists regardless of the alternator type. Reading through this pdf it seems very like it is the field effect transistor that has blown/shorted/failed. I'm not sure I'll be able to fix that myself though.

[Jack Chapman]

Originally Posted by wsmurdoch

Given that you have a Heart regulator, I'd suspect you have a modified 10DN General Motors alternator like this




or with the more usual fan

Thanks. Well it is fairly similar looking to that 10DN but the mounting bracket is different

[Boatyarddog]

Originally Posted by Jack Chapman

I am quite sure that it is externally regulated. If I disconnect the field wire from the regulator with the alternator spinning I read 12+ volts at the battery, if I connect the field wire to the alternator I get 14+ volts at the battery. Seems pretty clear cut to me...?

I'm fairly sure the fault is with the regulator itself though and the fault seems to exists regardless of the alternator type. Reading through this pdf it seems very like it is the field effect transistor that has blown/shorted/failed. I'm not sure I'll be able to fix that myself though.

Try that support number.
I did not see in reading back on these posts a reference to an N or a P type.

I believe you must be correct as to the problem is the Regulator.
Note that it seems to have a lengthy troubleshooting guide and that being said, there maybe problems with these units in general.

The internal configuration of an integrally regulated alternator is quite different, than the non regulated version.
It's why it's not compatable.
This is explained in that PDF.
Wish I could have been more help.


Boatyarddog

[wsmurdoch]

The components of the circuit for the field of an alternator can be in either of two orders.

1. Batt+ --- Regulator === Field Winding --- Batt- . This is called a P type alternator.

2. Batt+ --- Field Winding === Regulator --- Batt- . This is called a N type alternator.

The field wire (===) is the wire between the Field Winding and the Regulator. On a N type alternator the field wire is always hot with respect to the Batt- which in the usual case is the alternator frame.

This snip is from "The 12V Doctor's Alternator Book". The book is long out of print, but you should be able to find a pdf on the internet. It also contains sketches of alternators up to about 1985.