AC to DC Conversion W/ Floating Ground By Bashan (Read 29,439 times)

[noday]

this is one of those projects that is very simple in concept.....But when you get to the implementation, you have to stop and scratch your head at every twist and turn.

as far as I can tell, Trailtech just makes the 1 universal RR with different connectors.

I think they are designed for ATVs and motorcycles, not for GY6 based scooters.

the universal RR you found is probably a TT knockoff

Yes, it is confusing.... very.

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

part of what makes this example more confusing is the addition of windings to one of the poles.

the key point is floating & insulating the centertap.


after that it is a matter of making sure the two wires (white and yellow) are connected to the ends of the windings and protected from rubbing on the flywheel....... to decrease any future confusion, I would replace the white wire with a yellow one, so that you have 2 symmetrical yellows.



should be simple as pie, but that went out the window months ago.

I think you are on the right path.

good luck today

[Bashan]

I was able to move ahead a little bit on the investigational side of this. I'm not sure if I'm going to take the plunge yet and rewire the stator though. I pulled the stator and figured some things out and ran into some posers also. First, here's the stator looking at it from the front. The red dot is the attachment for the ignitor or CDI AC power feed wire, and the green dot is the ground wire:

By the pale blue dot you see a raised portion off of the stator body which is called the ground tab. This runs from the ground wire solder connector to the ignitor coil solder connector and provides a ground connection for the AC power circuit. The thing is, I couldn't get continuity from the ignitor connection to the ground:

558 Ohms was the best I could get. There's obviously a connection there or I couldn't get a reading so I guess that's enough for a ground. The stator and CDI were working fine before I removed them.

Let's look at the lighting and charging circuits. The stator winding starts at ground wire connection at the green dot, winds it's way around the seven poles in a route you just have to trace out to appreciate, and ends on the white dot where the white wire solders on. Here's the stator pic again:

The crux of the debate is the yellow wire. Look where it solders on at the yellow dot and it looks like two wires hook on there. Nope, it's one continuous wire and the yellow wire simply taps on at this point. Aha! The dreaded center tap! I can see how the stator works now, the magnets in the flywheel set up an AC current that shuttles back and forth along the white and ground wire through the rectifier for DC current to the battery. The yellow wire is grounded at various points throughout the frame for the lights so the current shuttles back and forth through the yellow and ground wire. I'm going to go back to the Trail Tech rewiring tutorial now and see if that stator is similar to the GY6. If so I might give it a go and get one of their R/Rs. My original intent was to find an easy plug and play method to get DC power for the GY6 without rewiring so it would be accessible for the novice mechanic. It looks like it's going to be a little more complex than that. Rich

[Bashan]

I looked at the Trail Tech rewiring and it's not the same, close but no cigar. The KTM stator doesn't have this mess for one thing:

As I said, you'd just have to trace that out to believe it. I'm sure it makes some electrical sense according to the design of the stator and wiring of the scooter but it's convoluted. The Trail Tech looks like a much more straight forward winding and the grounds are also different. So the Trail Tech R/R might not work. One option would be to take the yellow wire center tap off, redo the grounds, and hope the GY6 flywheel would work with a universal R/R; definately a big experiment. Another would be to rewrap the stator with a simple winding around the seven poles, hook the ends to a universal R/R, use the GY6 flywheel, and see what happens. Third option, quit farting around and go back to stock FLP R/R and reinstall the stator. Rich

[Bashan]

OK, I drew up a simple representation of this concept more for my own sake than anything else. Thought you were going to get rid of this thread didn't you? HAR! Fat chance. The GY6 stator wiring is basicall one long wire that snakes around the seven coils and is the ground wire on one end and the white on the other. The yellow attaches somewhere in the middle to that wire and therefore doesn't get as many windings to draw from which equals less juice. However, all the wires are contiguous and you will get a continuity tone from yellow to white to ground in any combination:

If you were going to go all DC off of the battery using a universal R/R you'd need to have one wire wrapped around the seven poles, lose the ground, lose the yellow center tap, and hook your R/R output right to the battery. I think you could probably use the GY6 stator wired like it is as long as you did these modifications.

Then whatever you're trying to power, lights, oil pump, etc., you'd hook up red and black to the battery. You could leave your yellow intact in the scooter and switch it right to the battery, all the lights are already grounded to the frame. You'd just need to have a frame ground to the battery of course. Does this make sense? Rich

[noday]

edit:
your stator makes no sense to me.... & it now makes sense why only 1 specific RR works

another option, the below ebay listing is in pounds or about $20 US for this stator

looks closer to the TT KTM and should convert with minimal problems

www.ebay.com/itm/8Poles-GY6-50-Moto-Engine-Sparking-Magneto-Stator-Coil-/250869207333?pt=UK_Motorcycle_Parts&hash=item3a68f85125



yes it makes sense.

edited: probably can get rid of the green (ground ) wire on this stator. after conversion... don't think that it is needed for the CDI trigger pulse

also you can see why winding are added to a pole in the TT guide...

a 12 V DC conversion has to end up with all things run from the battery

and the battery charged from the stator/RR, just like a car alternator/battery system

[Bashan]

That's a nice looking stator, very solid build. The windings look a lot more straight forward too. He sells them for 125s which I'm pretty sure would fit my scooter. I wish they woud give a mm measurement on the bolt holes though just to be sure.

I'm not sure why they have the poles wound like they do on my stator. I can see how it works, it's still just one long winding. I think what you'd have to do is keep a ground to the stator body for the ignitor coil and the trigger but get it off of the main winding. I did a little investigation on my flywheel and it's eight equally strong magnets arranged equadistant around the circumference. I didn't expect anything different and I'm sure that would work with any eight pole stator as long as the diameter was compatible. Interestingly, the trigger magnet square on the flywheel is nothing more than an extension of one of the eight magnets. I had always thought it was a seperately embedded magnet; live and learn. Rich

[noday]

that stator was just the cheapest one that popped up in a quick ebay search.

besides the hole spacing, another thing to check is the angle of the mounting holes v the trigger pole.

that ebay listing looks the same as your stock stator, to me.

when you draw a line from 1 hole to the other, what is the angle of the center of the trigger pole.?

will this affect the timing of the trigger pulse ?

some of the different stators have different angles of orientation.

my guess is probably no, as long as that pole is energised at the time of triggering.

this is one example that has a different mounting hole orientation and probably would not work properly



here is another that looks like the right orientation. costs a bit more & has hole spacing on the listing.... but can't see the wiring hookup. ships from US so less time for delivery


cgi.ebay.com/ebaymotors/Magneto-Stator-GY6-50cc-125cc-150cc-Moped-ATV-Go-Kart-/190572603675?pt=Motorcycles_Parts_Accessories&hash=item2c5f03291b



just some different things to look at and think about

[Bashan]

Lot's of good stuff to chew on, thanks. I 've about decided to rewire a stock GY6 stator by taking the off the yellow tap and the ground wire. Then I'll solder an extension wire off of the former green ground wire and use that and the white as the two wires to the universal R/R. I think I'll then solder a new ground wire on where the old one came off and ground it to the frame for the AC power circuit off of the magneto. I will leave the stator windings as they are and assume that since it is still just one long winding, albeit convoluted, it should still produce an equal AC current in both wires. This time I'll use the Trail Tech universal full wave rectifier, it's hardly anymore money than the Amazon R/R. If this works, a tinkerer rider should be able to convert to DC without too much difficulty. Will this work? I'm ordering a stator and R/R today. Rich

[Bashan]

I wrote the Trail Tech people to see if they think this would work with the center tap removed and the ground wire extended on the stator. If so I'm going to order the 010-ELV-71 R/R and see what happens. Rich

[Bashan]

Here is the e-mail I sent off to the nice people in the tech department at Trail Tech:

Hi, I'm the owner of Scooter Doc Forum. One of the big movements in the scooter field right now is to go to all DC electrical systems. I am trying to find a way to use the GY6 stator modified with minimal rewiring coupled with a full wave rectifier/regulator. From everything I've read I believe the Trail tech 010-ELV-71 is the best option. The GY6 stator is the type with a yellow wire center tap. The entire winding starts with the ground wire next to the magneto coil, winds around seven poles with a somewhat irregular path, and terminates on the white wire. As I understand this concept the whole winding must be ungrounded and the yellow center tap removed. My plan is to unsolder the green ground wire and attach an extension to it, remove the center tap and tape it off, then use the white and extended ground wire to attach to the two yellows on your R/R. I have read all of your tutorials and even though the GY6 is not identical to the KTM the concept would be the same in that it is one contiguous winding. Does this sound like it would work?

My second question involves the schematic for wiring the R/R in place. It shows that the R/R must not be grounded to the frame. In fact, the diagram shows no frame grounds at all on any of the circuits. Is this correct? It seems that there would have to be some connection to the frame to shunt excess voltage from the R/R. The scooter I plan on using this on is basically naked with just a headlight, tail light, oil pump (10 amps), and a cooling fan. It would be no problem with wiring these back to the battery but on a conventional scooter with many lights this might be problematic.

If I can make this work I think there would be considerable interest in this regulator as a realtively easy way to go DC. I don't believe your stators fit GY6 scooters do they? Here is a link to my scooter forum:
scooterdoc.proboards.com/index.cgi
And here is a link to the thread about the conversion using your regulator:
scooterdoc.proboards.com/index.cgi?board=150cc&action=display&thread=4872
Thanks, Rich Carman

Here is their response that took less that 12 hours to receive:

You are correct. The procedure that you described is called floating the ground. With this done it will provide you with the two lighting leads that are needed for hooking up our reg/rec and converting the power to DC. You will want to bolt the reg/rec to the frame as this is how it is grounded and shunts the power. And I am sorry but we do not offer a stator that will fit that application.


Looks like we have a green light. I'll order the R/R hopefully tonight and start rewiring the stator I have this week end. Hopefully I can have something up and working by early next week. I've got to get an ammeter together for this just to see what knid of draw it will really ave. I've got one for Ford tractor but the scale is so large it barely moves. I need something like 8 to 12 max. Rich

[Alleyoop]

FANTASTIC Rich, now I am by no means an Electrical GURU, but can you tell me in simple terms WHAT CHANGING it to a DC SYSTEM will give a scoot in return?
Alleyoop

[tvnacman]

steady non flickering lights !!!!

[Bashan]

I am going to have a huge drain on the battery with that 10 amp oil pump and 3 amp fan. This way I will have a full wave rectifier that will utilize all of the energy and all power will go the the battery. This way I can use all LED lights and hopfully will have enough juice for the charging system. Also, I hope this is a straight forward, relatively easy, modification that everyone can use with just the price of a Trail Tech R/R to go all DC. Rich

[Alleyoop]

ALL POWER WILL GO TO THE BATTERY? Meaning everything will be powered by the battery?
If so does that R?R put out a lot of Charge to keep the battery charged as it is being drained?

Flickering lights is not a concern of mine since I do not drive at night, during the day I run with the the Two side running lights on my Trike and my charging system is Great, at IDLE it is 14.5 and it stays there nomatter the rpms. IF I put the headlights on it drops unless It the RPMS are around 3000 or abovev. I have not checked the headlight bulb walts since I do not use them but I will and see if what watage they are.
Alleyoop

[Bashan]

Here's the R/R with a simple wiring diagram at the bottom:

Here's the schematic. as you can see there's no frame ground on any of the loads. The technition told me to make sure the body of the R/R is cleanly grounded to the frame as that is the excess voltage shunt point. You asked about advantages, this will give full wave rectification which will provide more energy. It's true that the lights won't flicker as much but that is not my main concern. Also, this will provide me one fuse panel to tie all of the components into. One thing that confuses me, if the R/R shunts to the frame it still has to have a circuit. I'm guessing the grounded stator will provide that. Rich