Uninstalling a Weems and Plath AutoMAC alternator control

[Maine Sail]

Currently I have a positive wire going from type N Alternator to the isolator diode. I plan on replacing with blue seas SI ACR.

An ACR is NEVER installed in the alternator circuit, only between battery banks.

Making Sense of Automatic Charging Relays - Marine How To

What about the red wire that is coming out of the alternator vent that used to be hooked to the automac's 4 amp fuse? Should I remove the alternator cover and remove the wire? Should it be hooked up to anything else? I also had another wire that was hooked to automat black with red stripe that went to control panel as well. I am inclined to hook up red wire that is coming out of vent to black and red striped wire that goes to the control guages. However dont want to fry anything.

That wire is not part of the original alternator design and we have no idea what was done inside the case. Looking at how sloppily it was done yields little faith in who did this. We have no idea if it was converted to N-Type or P-Type external regulation nor if the internal regulator is even still active. The Balmar regulators and Wakespeed WS100 are only P-Type external regulation.

The only way to know this is to remove the alt and bring it to a shop so they can figure it out. The SRE Frame (rear case) is pressed into the SRE bearing and really requires a shop that knows what they are doing to get that case apart, especially after years of being in the marine environemnt. At this point you may be better off to just invest in a new quality alternator, one that's already set up for external regulation, such as a CMI-80-ER..

 

[Rich Stidger]

The red wire that disappears into the case through a vent is most likely a direct connection to the field. Alternators that have internal regulation don't usually have the field connection available as an external connection. I had to make a similar connection on my OEM alternator on an Atomic 4 many years ago when I added a field boost circuit for higher rate charging.

 

[CMF Hunter 27]

Currently I have a positive wire going from type N Alternator to the isolator diode. I plan on replacing with blue seas SI ACR.

An ACR is NEVER installed in the alternator circuit, only between battery banks.

Making Sense of Automatic Charging Relays - Marine How To

What about the red wire that is coming out of the alternator vent that used to be hooked to the automac's 4 amp fuse? Should I remove the alternator cover and remove the wire? Should it be hooked up to anything else? I also had another wire that was hooked to automat black with red stripe that went to control panel as well. I am inclined to hook up red wire that is coming out of vent to black and red striped wire that goes to the control guages. However dont want to fry anything.

That wire is not part of the original alternator design and we have no idea what was done inside the case. Looking at how sloppily it was done yields little faith in who did this. We have no idea if it was converted to N-Type or P-Type external regulation nor if the internal regulator is even still active. The Balmar regulators and Wakespeed WS100 are only P-Type external regulation.

The only way to know this is to remove the alt and bring it to a shop so they can figure it out. The SRE Frame (rear case) is pressed into the SRE bearing and really requires a shop that knows what they are doing to get that case apart, especially after years of being in the marine environemnt. At this point you may be better off to just invest in a new quality alternator, one that's already set up for external regulation, such as a CMI-80-ER..

 

[CMF Hunter 27]

Currently I have a positive wire going from type N Alternator to the isolator diode. I plan on replacing with blue seas SI ACR.

An ACR is NEVER installed in the alternator circuit, only between battery banks.

Making Sense of Automatic Charging Relays - Marine How To

What about the red wire that is coming out of the alternator vent that used to be hooked to the automac's 4 amp fuse? Should I remove the alternator cover and remove the wire? Should it be hooked up to anything else? I also had another wire that was hooked to automat black with red stripe that went to control panel as well. I am inclined to hook up red wire that is coming out of vent to black and red striped wire that goes to the control guages. However dont want to fry anything.

That wire is not part of the original alternator design and we have no idea what was done inside the case. Looking at how sloppily it was done yields little faith in who did this. We have no idea if it was converted to N-Type or P-Type external regulation nor if the internal regulator is even still active. The Balmar regulators and Wakespeed WS100 are only P-Type external regulation.

The only way to know this is to remove the alt and bring it to a shop so they can figure it out. The SRE Frame (rear case) is pressed into the SRE bearing and really requires a shop that knows what they are doing to get that case apart, especially after years of being in the marine environemnt. At this point you may be better off to just invest in a new quality alternator, one that's already set up for external regulation, such as a CMI-80-ER..

@mainsail, yes I agree with you the Alternator should not be connected to the ACR. I was going to connect to the larger battery. Attached is my electrical schematic. I know I am missing something off the battery switch but this is the general setup. I left out the isolator diode because I was going wire up the acr today.
Thank you
Chris

 

[CMF Hunter 27]

The red wire that disappears into the case through a vent is most likely a direct connection to the field. Alternators that have internal regulation don't usually have the field connection available as an external connection. I had to make a similar connection on my OEM alternator on an Atomic 4 many years ago when I added a field boost circuit for higher rate charging.

Thanks Rich! I have never even had the boat in the water. I am going to push ahead assume it's has an internal regulator and see if my batteries charge off the current alternator if not I will buy new alalternator and an external regulator.

Thank you for everyone's time and all the current and past posts I have read and digested.

 

[Dalestr]

The AutoMAC is designed to be a manual booster to overcome some of the limitations of an automotive regulation system. It is wired in parallel to the regulator. If the regulator should fail, it could fill in while on a cruise. The wire coming out of the alternator case is likkely the connection to field which would be on the negative side of the field coil (at the brush based on the installation instruction) unless this alternator was changed to a P-type, which is unikely. It is actually rather easy to pull off the Alt. back casting along with the stator on these units when not much corrosion. I found use of a small impulse hammer driver the best way to loosen the four philips screws but heat and lube always helps. These alternators or their clones are getting fairly cheap online. One problem that you might consider with your limited 8HP is the ability to kill the load of the alternator when you really need full power on tap. Need to break field current for that.