I was looking at the wiring to my alternator this weekend. It has two contacts in the rear, one labeled BAT, and both leading to the voltage regulator. QUESTION 1: Is the other the field control to the alternator?
There are also three wires exiting the side of the alternator, unlabeled, apparently leading to the instrument panel. (I did not trace them their full length.) QUESTION 2: What are these? (Or rather, what are the other two. I suspect one is just alternator output for the display in the instrument panel. Does one power the instruments? And the third ..?) Unfortunately, there is no manufacturer name or model number on the alternator; I suspect it is original with the 1980 engine.
Finally, I am puzzled by the voltage regulator. It has no ground lead, nor is its casing grounded. It is mounted on the non-conducting compartment wall. The voltage regulator's only three leads are output from the alternator, what I assume is the field control to the alternator, and output to the battery. QUESTION 3: How does the voltage regulator measure the alternator's output potential, without a ground for reference?
DQOTD's about ALTERNATOR and VOLTAGE REGULATOR on Perkins 4-
Moderator: Jim Walsh
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Matt Cawthorne
Re: alternator - Perkins 4-108 in CD 36
Russel,
Your installation sounds like the one in the Patricia Louise. Since I can not see it to be shure you need to take this message with a grain of salt. My installation was done in 1982. I have since installed a Balmar alternator and regulator, but keep the old DELCO as a spare.
The thing on the engine compartment wall was not a voltage regulator on my boat. The stock alternator was internally regulated. I never did confirm what the box on the wall was, but I suspect that it was some sort of electrical noise supressor. The Two main wires attached to the back of the alternator were the alternator output and the ground. They both went to the little box and the third wire from the box went to the batteries. The third wire was an orange color on my harness, and was unbelieveably undersized for handeling the output of a 60 amp alternator. Because the alternator was getting upgraded and the box on the wall did not have a rated capacity I did a "thing-ectomy" and removed the unlabeled box.
One of the three wires connecting to the side of the alternator is the tachometer sense wire. It is connected through the harness to the back of the tachometer. Another wire from the side goes to the + side of the electrical system and is not switched. The third wire goes indirectly to the 'ignition' (key) switch. I would tell you what all of the colors were on the wires, but the colors were different on the opposite sides of the harness connector at the back of the engine which leads me to believe that the scheme had changed. For example the tachometer lead was white at the alternator but gray at the back of the tachometer. The switched wire was brown at the alternator and purple at the end where it attches to the switch. You will have to spend some time with a multimeter checking continuity to trace your own system. It seemed like a monumental task initially, but was not too bad.
Try disconnecting one of the three wires at the time from the side of the alternator and disconnecting the sense wire on the tach. A continuity check will quickly identify which is the sense wire at the alternator.
Disconnect one of the other two from the side of the alternator and you can quickly determine which is switched and which is not.
I had problems with the alternator because the switched wire was intermittently going open (same as turning the key off). As a result I have been bypassing the harness whenever work is done on some aspect of the electrical system that involves the harness. I hate the harness system on the Perkins 4.108. It seems like a good idea but with the change in colors across the engine connector and splices within the harness it is really tough to work with.
Good luck. I hope this helps.
Matt
mcawthor@bellatlantic.net
Your installation sounds like the one in the Patricia Louise. Since I can not see it to be shure you need to take this message with a grain of salt. My installation was done in 1982. I have since installed a Balmar alternator and regulator, but keep the old DELCO as a spare.
The thing on the engine compartment wall was not a voltage regulator on my boat. The stock alternator was internally regulated. I never did confirm what the box on the wall was, but I suspect that it was some sort of electrical noise supressor. The Two main wires attached to the back of the alternator were the alternator output and the ground. They both went to the little box and the third wire from the box went to the batteries. The third wire was an orange color on my harness, and was unbelieveably undersized for handeling the output of a 60 amp alternator. Because the alternator was getting upgraded and the box on the wall did not have a rated capacity I did a "thing-ectomy" and removed the unlabeled box.
One of the three wires connecting to the side of the alternator is the tachometer sense wire. It is connected through the harness to the back of the tachometer. Another wire from the side goes to the + side of the electrical system and is not switched. The third wire goes indirectly to the 'ignition' (key) switch. I would tell you what all of the colors were on the wires, but the colors were different on the opposite sides of the harness connector at the back of the engine which leads me to believe that the scheme had changed. For example the tachometer lead was white at the alternator but gray at the back of the tachometer. The switched wire was brown at the alternator and purple at the end where it attches to the switch. You will have to spend some time with a multimeter checking continuity to trace your own system. It seemed like a monumental task initially, but was not too bad.
Try disconnecting one of the three wires at the time from the side of the alternator and disconnecting the sense wire on the tach. A continuity check will quickly identify which is the sense wire at the alternator.
Disconnect one of the other two from the side of the alternator and you can quickly determine which is switched and which is not.
I had problems with the alternator because the switched wire was intermittently going open (same as turning the key off). As a result I have been bypassing the harness whenever work is done on some aspect of the electrical system that involves the harness. I hate the harness system on the Perkins 4.108. It seems like a good idea but with the change in colors across the engine connector and splices within the harness it is really tough to work with.
Good luck. I hope this helps.
Matt
Russell wrote: I was looking at the wiring to my alternator this weekend. It has two contacts in the rear, one labeled BAT, and both leading to the voltage regulator. QUESTION 1: Is the other the field control to the alternator?
There are also three wires exiting the side of the alternator, unlabeled, apparently leading to the instrument panel. (I did not trace them their full length.) QUESTION 2: What are these? (Or rather, what are the other two. I suspect one is just alternator output for the display in the instrument panel. Does one power the instruments? And the third ..?) Unfortunately, there is no manufacturer name or model number on the alternator; I suspect it is original with the 1980 engine.
Finally, I am puzzled by the voltage regulator. It has no ground lead, nor is its casing grounded. It is mounted on the non-conducting compartment wall. The voltage regulator's only three leads are output from the alternator, what I assume is the field control to the alternator, and output to the battery. QUESTION 3: How does the voltage regulator measure the alternator's output potential, without a ground for reference?
mcawthor@bellatlantic.net
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Jeff Barnes
Re: Thanks !!
Russell:
My CD36 (Jazman, #68) had the same alternator and wiring set-up as you described. The regulators for these alternators were internal, I believe, so any external box is prpbably not an external regulator unless the alternator was modified to accomodate it. One of the happier days of my life was when I heaved that alternator and replaced it with a 70 amp Balmar and external 3 stage regulator from Heart Interface. In addition to more rapid charging, the regulator ensures proper charging and battery maintenance in a "float" mode. It's a worthwile investment even if you have to hire a technician to do the installation.
Regards
My CD36 (Jazman, #68) had the same alternator and wiring set-up as you described. The regulators for these alternators were internal, I believe, so any external box is prpbably not an external regulator unless the alternator was modified to accomodate it. One of the happier days of my life was when I heaved that alternator and replaced it with a 70 amp Balmar and external 3 stage regulator from Heart Interface. In addition to more rapid charging, the regulator ensures proper charging and battery maintenance in a "float" mode. It's a worthwile investment even if you have to hire a technician to do the installation.
Regards