Question About AC Stator Sharing Ground with DC Circuit

Thread Starter

FftEMT1991

Joined Jul 8, 2018
5
Why is it ok for an ac motorcycle stator to share a chassis ground with dc/battery charging system?

Im not sure if this is a 3 phase or single phase stator, or really anything about stators except the basic principles of electromagnetic conduction.

My thought process is with AC stator 200 watts to chassis ground that it would maybe fry the battery from the dc ground to the negative terminal on the battery. And then a lower watt stock/oem stator would be not enough to worry about. Again i have no idea. Just wondering as i would like to wire my own bike and its super interesting. For me anyways.

So

Why is it ok in some cases for a motorcycle ac stator to share chassis ground with dc/battery charging system?

Below are two wiring diagrams for a bike that shows a shared frame chassis ground with a dc battery system.20180707_104644.jpg 20180707_104711.jpg
Below is the stator that i have for my bike. I would like to include a battery but it doesnt say anything about a shared ac/dc ground.
RSXR600_A-page-001.jpg
 

ian field

Joined Oct 27, 2012
6,543
Why is it ok for an ac motorcycle stator to share a chassis ground with dc/battery charging system?

Im not sure if this is a 3 phase or single phase stator, or really anything about stators except the basic principles of electromagnetic conduction.

My thought process is with AC stator 200 watts to chassis ground that it would maybe fry the battery from the dc ground to the negative terminal on the battery. And then a lower watt stock/oem stator would be not enough to worry about. Again i have no idea. Just wondering as i would like to wire my own bike and its super interesting. For me anyways.

So

Why is it ok in some cases for a motorcycle ac stator to share chassis ground with dc/battery charging system?

Below are two wiring diagrams for a bike that shows a shared frame chassis ground with a dc battery system.View attachment 155848 View attachment 155847
Below is the stator that i have for my bike. I would like to include a battery but it doesnt say anything about a shared ac/dc ground.
View attachment 155846
The only one I ever saw do that was when a loose crash-bar chaffed through the cabling.

AFAICR: only flywheel generators have grounded generator windings and a half wave rectifier.
 

Thread Starter

FftEMT1991

Joined Jul 8, 2018
5
The only one I ever saw do that was when a loose crash-bar chaffed through the cabling.

AFAICR: only flywheel generators have grounded generator windings and a half wave rectifier.
The copper windings on the stator are stationary and the flywheel rotates around them.

Why does the generator need to be grounded? Purely safety? Or to complete an ac curcuit?

Am i just reading the diagram incorrectly?
 

ian field

Joined Oct 27, 2012
6,543
The copper windings on the stator are stationary and the flywheel rotates around them.

Why does the generator need to be grounded? Purely safety? Or to complete an ac curcuit?

Am i just reading the diagram incorrectly?
Most alternators are a stator ring with a rotor spinning in the middle.

Most alternators have floating windings.

Most alternators feed a 2 or 3 phase bridge rectifier.

Some 2 phase stators look like 3 phase stators - heavier set of windings switched in when main beam on.
 

-live wire-

Joined Dec 22, 2017
887
One thing to keep in mind is that by using a metal chassis as ground, you don't have to use as many wires. Wires can get expensive if they have to carry such high currents, or if they have to be very durable.
 

Thread Starter

FftEMT1991

Joined Jul 8, 2018
5
One thing to keep in mind is that by using a metal chassis as ground, you don't have to use as many wires. Wires can get expensive if they have to carry such high currents, or if they have to be very durable.
This is for aan off road dirt bike, 85 xr600r, that origional runs only on ac current. No electrical start battery or turn signals. Just kick start to stator/alternator/generator one set of coils to ignition and another set to ac lighting system. Im going to be adding a battery and im not sure if its ok to have the ac system chassis ground with the dc system. Ill find out more about the stator if its 1 2 or 3 phase. Ill be calling the company to ask specifics tomorrow.
 

Thread Starter

FftEMT1991

Joined Jul 8, 2018
5
Most alternators are a stator ring with a rotor spinning in the middle.

Most alternators have floating windings.

Most alternators feed a 2 or 3 phase bridge rectifier.

Some 2 phase stators look like 3 phase stators - heavier set of windings switched in when main beam on.
This alternator has a flywheel mmagnetothat spins around the stationary coils.

What do you mean by floating windings?

I will find out how many phases it has.

Thanks for the responses. Newbie here tryin to figure it out haha.
 

ian field

Joined Oct 27, 2012
6,543
This alternator has a flywheel mmagnetothat spins around the stationary coils.

What do you mean by floating windings?

I will find out how many phases it has.

Thanks for the responses. Newbie here tryin to figure it out haha.
Not familiar with that model, but I'd expect something like a "spider stator" It should be similar to a flywheel generator in some respects. AC lighting is likely to be grounded. Ignition is usually CDI with a high voltage winding on the "spider" feeding a "black box" module - the wiring is usually mostly sealed in. Floating means no earth - that happens on the other side of a bridge rectifier.
 

Thread Starter

FftEMT1991

Joined Jul 8, 2018
5
Called ricky stator and bought a multi-meter. Here's the rundown.

Everything good. Resistance to spec on black/red to ground (Spec 90-110ohms. tested at around 93ohms) continuity between double green connector and double white connector, and continuity between single white and single green. Meter reads infinite resistance between the two whites, as well as between the two greens. So everything is dandy.

NO SHORTS!! (and i was happy to experiment with a multimeter for the first time on my own!!)

Awesome guy at ricky stator helped me out. Heres the run down on the stator.

12 coils. The 2 insulated with fiberglass tape are ignition coils. black/red is hot and ground to the stator core. which means ultimately ground to engine and to chassis

The other ten coils are single phase and to quote Mike at ricky stators, "Its a single phase stator wound in such a way as to enable multiple outputs". i didn't ask but i assume 2 coils single phase dedicated output for ignition, and two different sets of 5 coil single phase each with dedicated outputs. (5+5+2=12 coils) Sort of like 3 single phase stators in 1 package!

i was correct in assuming that the green was hot and the white was neutral. mike said it didn't matter which is hot or neutral because its alternating current . This makes sense to me but i'm glad that my thoughts about the matching double connector white and green wires is one circuit, and the other single connector white and green wires are another circuit.

And i figured out my wiring config.

black/red to ignition system. join the 2 green wires together and the two whites together, and connect the Regulator/Rectifier up to each one respectively. (kind of like wiring two separate single phase stators together) Then connect the Reg/Rec to the battery. So i have a dedicated ignition system and a 200 watt 2 phase stator to power my diy custom charging/lighting configuration!!

One final notice.

Mike at Ricky Stator said that it really doesnt matter if the a/c circuit shares a ground with the d/c circuit. Which makes sense since Honda apparently has been doing this for literally decades. I still don't know why as it confuses me.

so i will probably just ground the dc system to anything except me and end up floating it anyways

(P.S. Does anyone know what kind of epoxy i can put on those nicks without curing it in the oven? would liquid electric tape work? the stator is bathed in oil but doesn't move/rotate. So i need something that can stand oil, vibration and some heat)
 
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