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rudolph
17th December 2008, 18:53
dose anyone know about tricks to get 12 volts out of a 6 volt DC generator?

I was told you could some times adjust the cut out on the regulator or replace the regulator with a 12V one, it is imposable to find 12-volt field coils.

Another way was to put a light bulb in between the wire to the field but all this would only run your 12 v headlights for a couple hours.

Dont say get an Alternator.

Motu
17th December 2008, 20:39
I seem to remember you could run 12 volt bulbs straight off them - join the field wire to the output so it's supplying it's own feild voltage.It will be very dim at low revs,and will blow the bulb if revved too high.

Just get a 12volt genny and go solid state reg.Wish we had those available back in the day.

Ixion
17th December 2008, 21:44
Hm. This used to be done a bit in the 50s. It was never very successful, and only worked on some gennies (and not very well even then).

If I recall (but it was a LONG time ago), you need two 6v batteries in series. Centre tap to supply the field, and then wind the regulator up to get the output voltage as high as the genny will produce. Some gennies could produce something near 12V (actually, of course you need about 13.6V). For a while.

Centre tapping the batteries also allowed you to retain the 6v starter which otherwise would have been a problem .

davereid
18th December 2008, 07:10
If I recall (but it was a LONG time ago), you need two 6v batteries in series. Centre tap to supply the field, and then wind the regulator up to get the output voltage as high as the genny will produce. Some gennies could produce something near 12V (actually, of course you need about 13.6V). For a while.


Increasing the current through the field winding will increase the generator output voltage. But as Ixion has pointed out, the extra field winding current will potentially destroy the field winding.

Can you change the gearing to the generator ? (is it a car one on a belt ?) Doubling its rpm will allow it to generate a higher voltage as well.

In this case, you may be able to reach 13 v by adjustng the regulator.

Either way, the life span of the genny will be limited.

jonbuoy
18th December 2008, 10:01
DC to DC converter would do it, keep the 6v electrics for everything else and just run it for the headlight.

rudolph
18th December 2008, 11:01
I seem to remember you could run 12 volt bulbs straight off them - join the field wire to the output so it's supplying it's own feild voltage.It will be very dim at low revs,and will blow the bulb if revved too high.

Just get a 12volt genny and go solid state reg.Wish we had those available back in the day.

un regulated field saw the volts to go up to 130 lol

rudolph
18th December 2008, 11:06
Hm. This used to be done a bit in the 50s. It was never very successful, and only worked on some gennies (and not very well even then).

If I recall (but it was a LONG time ago), you need two 6v batteries in series. Centre tap to supply the field, and then wind the regulator up to get the output voltage as high as the genny will produce. Some gennies could produce something near 12V (actually, of course you need about 13.6V). For a while.

Centre tapping the batteries also allowed you to retain the 6v starter which otherwise would have been a problem .

Someone sed using a 8-volt battery can work well and you don't have to change anything, but I have never seen a 8 volt battery in my life, the 6-volt starter likes 12-volts, I was told it will be ok.

xwhatsit
18th December 2008, 11:34
What's wrong with 6V anyway? My Cub has pretty crappy lighting but it's not that bad, and it's a scooter anyway; not like you're riding it through the unlit countryside in the middle of the night very regularly.

rudolph
18th December 2008, 17:55
What's wrong with 6V anyway? My Cub has pretty crappy lighting but it's not that bad, and it's a scooter anyway; not like you're riding it through the unlit countryside in the middle of the night very regularly.

I want to convert the bike but mostley I wont to convert a car as its near imposable to start

Motu
18th December 2008, 21:40
So what is it you are converting,car or bike? If it's the B31,you are sunk...it has no starter.Go for a modern 12 volt genny.If it's a car,just slap on a 12 volt generator and regulator...something like a Lucas C40.Change ignition coil and bulbs and use 12volt sparkplugs,everything else will work real well.....the horn will be very loud,and the starter turn over twice as fast.So long as the engine is in good condition it will start easy and the starter will handle the very short bursts.

Jantar
18th December 2008, 21:49
The voltage produced by a DC generator is dependent on the field strength and the the speed of rotation. So to change a 6V gen to 12v simply replace the regulator with a 12V one and double the speed of the generator. Measure the DC resistance of the field coils and add a similar sized resistor to the field circuit. :done:

rudolph
20th December 2008, 08:18
So what is it you are converting,car or bike? If it's the B31,you are sunk...it has no starter.Go for a modern 12 volt genny.If it's a car,just slap on a 12 volt generator and regulator...something like a Lucas C40.Change ignition coil and bulbs and use 12volt sparkplugs,everything else will work real well.....the horn will be very loud,and the starter turn over twice as fast.So long as the engine is in good condition it will start easy and the starter will handle the very short bursts.

Yer I want to convert the B31 and my Flathead V8 car, I carn't change to a 12 volt genny with out grate expense

JMemonic
20th December 2008, 18:45
Yer I want to convert the B31 and my Flathead V8 car, I carn't change to a 12 volt genny with out grate expense

The car should not require great expense, alternator and a regulator, new battery, bulbs, and the coil. The wiring should be all ok with it the way it is as its designed for 6 volt thus specd for higher currents that are applicable for 12 volts, ok the starter might be an issue but not much of one.

Likewise any bike, I am sure if you hunt around you will find someone who can rewind your current generator for 12 volts, the starter also, the biggest issue I could see would be the battery box size.

rudolph
20th December 2008, 21:06
Due to nostalgia reasons I can not use an alternator.

Motu
20th December 2008, 22:44
I've seen plenty of Lucas generators on flatheads.....but the crab dist is a problem.Later model engines with the normal dist would be better to convert.

rudolph
21st December 2008, 11:55
I've seen plenty of Lucas generators on flatheads.....but the crab dist is a problem.Later model engines with the normal dist would be better to convert.

I have Lucas generators witch are proper flathead ones, I think AC-DELCO is the other brand, I think I am stuck with 6-V.

Ixion
21st December 2008, 17:40
AC Delco would have been the original for a flathead, unless it was a Ford Pilot.

Later Yank tanks used 12V gennies, have you tried Ebay?

rudolph
22nd December 2008, 10:25
AC Delco would have been the original for a flathead, unless it was a Ford Pilot.

Later Yank tanks used 12V gennies, have you tried Ebay?

The flathead generator has a funny mount witch makes it near imposable to mount another non flathead generator unless its poasable to swap the armature compleat with front mount/cover.