News:

Due to a technical issue, some recently uploaded pictures have been lost. We are investigating why this happened but the issue has been resolved so that future uploads should be safe.  You can also Modify your post (MORE...) and re-upload the pictures in your post.

Main Menu

6volt alternator wiring?

Started by baxterculver, July 14, 2007, 10:15:09 AM

Previous topic - Next topic

0 Members and 1 Guest are viewing this topic.

baxterculver

I am installing a 6v (pos grnd) alternator in my '39 Cadillac.  The brief instructions that came with the alternator says to connect the one Alt output terminal  to the "Batt" terminal on the voltage regulator. 

Because I rewired the car (YNZ wires) I would prefer not to run a new wire from alt to reg.   Rather I would prefer to use the "Arm" wire that connects to the "Gen" terminal on the regulator, by switching it to the Batt terminal.  (following this?)  But when I do so, the starter doesn't work.  I know there is a "reverse current" between the reg and the starter circuit and it is spliced into the "Arm" wire.

Is it possible to do what I am trying to do??  Has someone else installed a "one-wire" alternator in a pre-war Cad or LaSalle?
baxter culver clc#17184

TJ Hopland

Im no expert but I think a 1 wire alternator has a built in regulator.  The reason they tell you to wire that to the BATT terminal of the regulator is that is the wire in the old system that would connect to the system.  I think you can remove the regulator and cap off all the extra wires.   The alternator wire just needs to hook onto the - (in the case of a + ground) somewhere with a large enough wire to handle the capacity of the new alternator.   If its a 42 amp alternator it should be at least a #10 wire.  Larger is always better (except for cost these days).   A circiut breaker, fuse, or fusible link wire may not be a bad idea either.  Your amp meter may not work anymore unless it has its own internal or external shunt.  If it does have a shunt you will want to check its capacity.
StPaul/Mpls, MN USA

73 Eldo convert w/FiTech EFI
80 Eldo Diesel
90 CDV
And other assorted stuff I keep buying for some reason

Greg Calkin CLC 18288

Baxter,

1939 & 1940 Cadillacs (probably other years too) have a safety feature to protect the starter from a driver that might engage it while the engine was running.  Wiring diagrams and descriptions in the service manuals show the starter relay ground wire connected to the Generator terminal on the voltage regulator. Thus, the connection to the cutout relay in the voltage regulator, causes a ground to exist when the engine is not running, but no ground to be available when the engine (and generator) are running.

To use your "one-wire" alternator you need to disable this circuit and create a permanent ground.  Remove the original starter relay wire from the starter relay ground terminal and make sure it is well insulated and secured so that it cannot come in contact with ground.  The other end of this wire is connected to the armature wire, so it will always be "hot" from now on.

Now make up a new wire and connect it between the starter relay ground terminal and the chassis.  You will now have to be careful not to engage the starter when the engine is running.  The starter will not engage unless the key is on, but pushing the start button will engage the starter even with engine running is running. 

With a one-wire alternator installed, placing the voltage regulator Generator wire on the Battery terminal makes for an easy installation.  The generator field wire should be inactive and can be left in place.  The one-wire alternator setups usually require the engine to reach a certain engine speed (1000 - 1400 rpm) on startup before they begin charging.  Once activated, they will usually keep charging even at low engine speeds.

You can easily go back to your original generator setup by reversing this process. 

I’ve seen some information on this forum stating that the one-wire setup constantly draws power while your car is sitting, and will kill the battery even over short periods.  I have not been able to measure any current draw with current one-wire setups such as “Gener-Nator”.  Perhaps battery killing was a feature of early one-wire systems.

Greg Calkin CLC 18288

baxterculver

Quote from: Greg Calkin CLC 18288 on July 15, 2007, 08:29:18 PM
Baxter,

1939 & 1940 Cadillacs (probably other years too) have a safety feature to protect the starter from a driver that might engage it while the engine was running.  Wiring diagrams and descriptions in the service manuals show the starter relay ground wire connected to the Generator terminal on the voltage regulator. Thus, the connection to the cutout relay in the voltage regulator, causes a ground to exist when the engine is not running, but no ground to be available when the engine (and generator) are running.

To use your "one-wire" alternator you need to disable this circuit and create a permanent ground.  Remove the original starter relay wire from the starter relay ground terminal and make sure it is well insulated and secured so that it cannot come in contact with ground.  The other end of this wire is connected to the armature wire, so it will always be "hot" from now on.

Now make up a new wire and connect it between the starter relay ground terminal and the chassis.  You will now have to be careful not to engage the starter when the engine is running.  The starter will not engage unless the key is on, but pushing the start button will engage the starter even with engine running is running. 

With a one-wire alternator installed, placing the voltage regulator Generator wire on the Battery terminal makes for an easy installation.  The generator field wire should be inactive and can be left in place.  The one-wire alternator setups usually require the engine to reach a certain engine speed (1000 - 1400 rpm) on startup before they begin charging.  Once activated, they will usually keep charging even at low engine speeds.

You can easily go back to your original generator setup by reversing this process. 

I’ve seen some information on this forum stating that the one-wire setup constantly draws power while your car is sitting, and will kill the battery even over short periods.  I have not been able to measure any current draw with current one-wire setups such as “Gener-Nator”.  Perhaps battery killing was a feature of early one-wire systems.

Greg Calkin CLC 18288

Greg--
Your advice was right on!  I thank you.  I changed my wiring a little bit different than your suggestion:  I left the Arm wire in place on the regulator but disconnected it (and taped it off at the generator location).  Then ran a new 10guage wire from the new alternator to the Batt term of the regulator.  That way, if I need/want to reinstall the generator, all the wires are in place to easily do so--just pull the new alt wire out of the way.
Thanks again for your help.
baxter culver clc#17184

harvey b

hello baxter, i am interested in how your 6v alternator is working out,i have a 37 60 series with a generator that isnt what i hoped it would be,battery always seems to be a bit low,hard starting when hot?.where did you get yours at,i have seen them on ebay,i am not concerned with looks,i just want to be able to drive the car.thanks Harvey Bowness
Harvey Bowness