I have a 6 volt system in a 1926 T. When I check the voltage at the generator terminal I get 9.5 to 10 volts with the engine running at idle to about half speed. When not running I get 0 volts at the generator terminal and 6.2 volts at the output (battery) side of the cutout. Do these voltages sound ok? My ammeter generally shows about 8 to 10 amps when travelling down the road at 20 mph or so. This week I plan to replace my stock cutout with a Fun Projects voltage regulator and would like to know if the 9.5 to 10 volts is too high for the Fun Projects regulator.
Thanks for any replies. Regards...
Third brush generators are stoopid.........they don't know what they are doing, 6V, 12V or more volts.......they don't care.
Your ammeter readings are good.
I have John's regulators on all three of my Fords......I finally got around to putting one on my '29 Model A on yesterday.......
(Be SURE which polarity your ground is!)
I hate to give you a green light since whether or not that voltage is OK depends on a lot of unknowns. If your meter is really a very accurate analog type meter then your readings would indicate your battery is low at 6.2 since a fully charged battery would be in the 6.3 to 6.4 range and you didn't indicate what the battery voltage was at the battery side of the cutout with the engine running when the charge rate was 8 to 10. More important than your readings would be for me to ask whether there is any oil inside the generator on the armature. Also check the full range of the 3rd brush adjustment to verify that the charge rate goes to near zero at high RPM when the 3rd brush adjustment is set to minimum. Then make sure that nothing funny happens when you advance the third brush setting to about 15 amps at high RPM and that the 3rd brush setting does that without the adjustment getting too far above about half way in the mechanical range. Do all of this with the lights off. If you do not know the history on your generator then there is always a risk since there can be lots of things inside that are ready to cause problems like frayed wires and such. At least pull off the dust cover band and have a good look inside to see if you see any bare wires or worn out brushes...etc. Eyes might be your best tool. Installing a VR onto a questionable generator is never a good idea. VR's can be repaired but it is unwise to not know what is going to happen and then decide to just "try it". Most of what I have said here is simply following the instructions to the letter as per the sheet that came with your VR. Do not proceed beyond any step if that step didn't work as expected. Hope this helps.
Thanks for your reply. This morning I pulled the cover on the generator and took a look inside. Found no oil but the commutator could be cleaner - not burnt but a bit dirty and oxidized. Didn't see any bad wires or insulation. I have a Simpson 260 analog meter and checked the voltage with the engine running. Generator (input) side of the cutout was 12 volt and the battery (output) side of the cutout was 11 volt. Engine not running reads 6.2 volt on output side. Believe I will take it apart and treat it to a new set of brushes and good cleaning. I have a spare generator that looks just as good and pulls 7.5 amps when it is motorized. Thinking about going through my spare generator (i.e. disassemble, cleanup, inspect, replace any worn parts) and using it with one of your regulators to minimize the downtime. I have the MTFCA book "The Electrical System" to use as a guide. Sound like a good plan?
Joe those voltages are way off track for a 6V setup. Check to see that when you have the 11V at the cutout - what voltage you then have across the battery measured directly across the battery terminals using the same meter. Do that before you go any further.