AC to DC Conversion W/ Floating Ground By Bashan (Read 29,402 times)

[Bashan]

OK, here's the deal, I'm working on my Frankenscoot to get the oil cooler I installed fully functional. It's working pretty decently and I'm trying to get all of the electrics finished up. I ran into this on Amazon and thought it might work well for using an all DC system since the Carter pump for the cooler is DC:

It's a universal regulator/rectifier for 12v engines. The idea is you hook any AC input on each yellow wire and you get 12v DC off of the red wire. So I figure the white goes on one yellow, the yellow on the other yellow and boom, pure DC. They weren't real clear in the description what the black was supposed to do but it was supposed to come with instructions. Well big surprise, no instructions. Here it is wired into Frankie:

The weird thing here is that if I leave the black wire unhooked I get a good strong 14.5v DC into the battery. If I hook the black up as a ground the voltage goes down to 13v DC on the red wire. If I test the black wire with the multimeter in series it gives 8v DC and also 10v AC. I'm thinking the black may be designed to power the autochoke. I've got a simple DC circuit hooked up for the autochoke so I really don't need the black wire for that anyway. So for right now I'm just leaving the black unhooked and reaping the extra voltage into the battery. Does anybody have any thoughts on the black wire and what's supposed to be going on here? Rich

[sprocket]

Hi Rich
I doubt the black is a ground, just leave it unhooked if nothing is smoking.. how hot is the R/R running?

[Bashan]

Excellant point, I haven't explored that little aspect yet . I haven't seen any smoke so that's a good thing. I'll have to let it run a while and put my hand on the R/R to see if it's getting too hot. If this thing works it's a pretty simple way to convert to an all DC system. It's certainly not an 11 coil three phase but it certainly seems to be pumping out some DC voltage. I've got an ammeter from Tractor Supply I'm going to install also to give me some idea of how much juice this thing is actually making. Rich

[sprocket]

I run mine at 14.5 volts also...never had any battery problems and my R/R is warm but not nearly approaching hot...

[noday]

thought I would just drop by and say Hello.

This is a topic I have spent some time exploring.

Black should go to battery (-)

your stator needs to be modified to "float" the AC output.

using a full wave RR without modifying the stator is most likely to burn out some of your components.

the thread I am linking is a bit long but should explain things,

there are full diagrams in the links in that thread.

scooterrebels.proboards.com/index.cgi?board=general&action=display&thread=1581

[sprocket]

Nothing says it is a full wave ...usually the ground is floated in single phase full wave applications...but I could be wrong...

[Bashan]

Thanks, very interesting reading. So you think this R/R I bought off of Amazon is a full wave rectifier like the Trail Tech? The tech guy at Scooter Dynasty insisted that this R/R was compatible with the GY6 8 coil stator. I felt a little guilty buying from Amazon after talking to the guy but they were $15.00 cheaper . Rich

[noday]

if you assume ( with all the risks that entails) that the wire colors followed convention, then the 2 yellows have no polarity and this would be a full wave rectifier. if the wires were different colors yellow & white then you would guess that there was AC polarity ( as in the stock GY6 4 wire RRs)

this appears more or less the same as the TrailTech without the blue lead. since that blue lead is only for small (4AH batteries to limit charging rate )

if this RR was made for an engine with a larger battery (?) then there is no need for a separate limited charge rate circuit.

of course it would be nice to know what engine this RR is designed for.

from Yahoo Shopping
"Product Description: SPORTS PARTS Universal Regulator/Rectifier 01-154-16
Designed to rectify A.C. output current to D.C. voltage. Replaces all selenium (metal plate) and silicon rectifiers. Protects batteries, lights, and complete electrical systems. 12 volt 200 watt (or less). Replaces regulators used on ARCTIC CAT, KAWASAKI, RUPP, SCORPION, SKI-DOO, and others."

from Scooter Dynasty

yellow: to both leads from lighting coil
black to ground
red to positive lead or battery

www.scooterdynasty.com/vrrectifieruniversalfor12vengines.aspx

a pdf with that same RR listed

www.fullthrottletahoe.com/fullthro/publicstore/images/catalog-specs/09SnowPages/09Snow%20243.pdf

looks full wave to me.

[sprocket]

I would say it isn't the same as the Trail tech... the Trail Tech has more wires if I recall...like a blue one etc...perhaps the 8 coil stator has a floating ground.. I seem to recall somewhere that it does , but maybe it is just the 3 phase 11 poles that do...

[noday]

some GY6 8 pole stators are full wave. most are split AC DC half wave types.

I think the full wave types use a DC CDI

the blue wire for the TT is not used if battery is 7AH or larger

plus if this actually works in Bashan's system, it has to be grounded thru the stator.

DC needs to be paired, both a ) and (-) lead

I do not think this is a direct swap for the usual stock GY6 RR without some modifications

[Bashan]

I'm back, is it just me or is TV just unwatchable anymore? Oh well, it gave me time to think about the rectifier while that vapid TV show droned on. There's been a leap here possibly without foundation. Even if that is a full wave rectifier why is that a death knell for the system? The unit may take what AC current it's given and produce whatever DC it can. So it's not totally efficient with that set up, does that mean it's going to burn up? I actually think the regulation to 12v would be more of a problem than producing DC current, there's some heat involved there. Well this will provide some good reading and research tomorrow but for tonight I'm a little too burnt to think about it any more. This is a good discussion though, we'll continue on I'm sure. Rich

[Bashan]

I've been thinking about this while actually trying to be productive at work at the same time. I recalled a lengthy discussion related to this on an old thread and remembered a wiring diagram we had come up with for the modern GY6 regulator/rectifier. I think this may explain why this universal R/R will work with my bike, and possibly many more like it. The diagram we came up with for the 150cc GY6 R/R was distilled off of a couple different threads on other forums. I can't remember which forums or I'd give them some creds. Now I'll say this again, I'm a chiropractor, not an electrician, and not a scooter mechanic. I find this stuff fascinating, have read a lot about these things, and have dismantled my poor scooter so many times it tries to hide from me. But punch holes in my suppositions, I don't care, I'm not offended, and welcome the discourse. Here is the diagram that I believe is the OEM R/R for my Bashan 150 and a gazillion other Sinoscoots:

Now the reason I think this universal R/R works with my stator is you'll notice a diode bridge at the heart of the Bashan R/R that constitutes full wave rectification. The bridge is fed by two AC sources from the stator, the yellow and white wire. In typical Chinese scooter fashion, they want the easiest of both worlds, a yellow 12v regulated AC wire for most of the lights, and a 12v DC red wire for the battery that is powered by the rectified white AC. Apparently the white and yellow AC feeds from the stator are enough in synch that they can both work off of the common circuit that is both power for the battery, and a yellow AC wire that can be tapped anywhere along it's length. Now, the universal R/R is essentially the same type of circuit in that it has a diode bridge at it's heart for full rectification. The difference lies in that it is designed for a single "lighting coil" as it's power source. Go ahead and Google that one if you'd like a small aneurysm to develop. As best as I can tell that is a coil dedicated for generating electricity. So for the universal R/R you have the two yellow wires that are designed to accept the two wires of a single AC circuit. The juice is rectified and regulated to 12v DC and you have the red and black wires coming off of it for the DC circuit to the battery. So the GY6 stator on my bike generates an acceptable AC power source, albeit from two seperate "lighting coils", that the universal R/R can still turn into DC power. However, I still come back to, what's up with the black wire!? I realize that if the universal R/R ws getting the power source it was ideally designed for the black would simply be the ground. Why the unit works better on my scooter with the black hooked up to nothing still confounds me. I'm sure it hs something to do with the way my GY6 stator is grounded. I can tell you for sure that it is grounded to the frame because I've had that puppy apart and multimetered countless times. How that works into all of this will require some more thought. Anybody got any thoughts on my theory? Rich

[sprocket]

My head hurts Rich!!!

[noday]

interesting Bashan and I do agree with your conclusion.

but and it is a big but.... I expect you are still getting the same amp/watt output from the new RR as with the old. ie: half wave rectification.

this is because your stator is grounded at the centertap.

to get full wave AC to DC (2 X the amp output of a half wave) conversion, that center tap ground is detached and insulated. (per TrailTech)

a full wave rectifier takes a peak to trough AC voltage, splits the voltage, and then converts both halves to a ) 12-14.5 V DC with respect to the battery(-).

one of the big rubs in exploring the possibles of these components is the near absolute lack of any real documentation for the components.

TrailTech has more info on its Universal RR than any other source I have found and that simply consists of a watt rating and a simplified wiring diagram guide for hook up.

I wish there was a simple way to "bench" a stator/flywheel with different RRs and measure outputs

to do the full conversion to DC I would follow the TT instructions as I know of no other guides to follow.

trailtech.net/media/electrical/dc_conversions/ac-dc_key_concepts.pdf

trailtech.net/media/electrical/dc_conversions/ktm_dc_conversion.pdf

www.trailtech.net/media/instructions/lights/regrec/010-ELV-71.pdf

[tvnacman]

Rich , try putting the black wire to switched power . look at the diagram of the 11pole 7pin conversion/hid .

when I did the above with 11pole 7pin I got at idle great voltage 14.5 vdc and it did not increase with RPM increase . (without the black wire connected ) . with the black connected to switched power at idle I get 13.3vdc then it increases when reved up .

MR . Sprocket is your head spinning in the other direction . or is the other side of your head hurting .
I bet I know what Rich will be doing tonight !!!! sorry Sue

John