generator or alternator

[jwhughes3]

Is the unit in the XS1100 a generator or an alternator? I've heard it referred to as both and I wanted to do some research and needed to know what type it is.

I remember back in 70s or 80s taking my alternator from a 64 mustang to a local alternator shop in Houston (nice thing about big cities is all kinds of places that do widget work) and had it rewired - I don't remember the details he told me but essentially he rewound the thing inside the same housing with different length of wire to boost the output from 60 to 85 amps - It cost me like $45 which was about the cost of a replacement at the time but I did not trust rebuilt alternators from unknown sources back then and high output units were more than twice that cost. (I used to take water pumps to a shop by the Port and get those rebuilt for like $25 too)

Could we not take the unit and have it custom wound to boost output by 15-20% and get maybe another 10 amps in what would appear to be a stock configuration?

John

[b.walker5]

Hi John,

It's a chicken and egg question and you'll get many different opinions. Being a sparky I have mine, but our bikes have a hybrid type of system thats open to interpretaion. Best suggestion is read up everything you can on both and make up your own mind.

This article is a good start http://www.electrosport.com/technica...g-system-works

[cywelchjr]

Don't think it's chicken and egg. It's an alternator, as it generates an alternating current that goes to a rectifier bridge that turns that into dc current. There are some who might try to argue that it's an AC generator, but that's not a term I have heard used in vehicles, only in power generation. Typically in vehicles a generator is only referred to as that if it used brushes and a commutator to generate DC current directly without AC current in any part of the system other than the coils themselves. (generators typically create current in the spinning portion of the unit and alternators typically create the current in the stationary or stator portion of the unit as well). There may be exceptions to this rule, but in my years in communications electronics in and out of the military I never saw any.

[jwhughes3]

spinning armature

@Brian - thanks that is a site with simplified terminology.

@Cy - that's more what I was looking at - a generator has a spinning armature in a stationary field and the alternator (traditional sense) is opposite and the field rotates in stationary coils.

I was looking at parts diagrams and it LOOKS like the armature spins on ours which makes it a generator - though I also heard it referred to as "brushless" and that cannot be the case with power generating as I understand it....

I think I should be able to get this thing re-wound - I just want to learn up on it in advance of going to find a shop so I know what I am asking for and getting back.

I think I would acquire a second unit and have it done so I could continue to ride - I am also thinking I might need to beef up the wiring a gauge or two if we increase the amp output.

John

[TopCatGr58]

Hey JW,

You may want to do some searching in the tech disc forum, many folks have checked this option out, and have come away with either it's too expensive for what little power you get, or there's not enough room in the housing to add much wire that would increase the output substantially.

The ROTOR spins inside the space between the field coil and the Stator Windings, it causes the magnetic fluxes that induce the current flow thru the stator windings to make the AC current.

There was some other details about the problems with the Stator windings, either they had to be smaller to be able to put more windings in the space provided, and that reduced output in some way...I'm not an Elect. Guru.

But this was why I went to the effort to do the Mini Alt mod.

But I'm sure folks would be very interested to see what you are able to come up with and how much it costs and how much extra power you can get. Keeping the OEM configuration would be very desirable if it can be done at a reasonable price.

Let us know! T.C.

[cywelchjr]

@Brian - thanks that is a site with simplified terminology.

@Cy - that's more what I was looking at - a generator has a spinning armature in a stationary field and the alternator (traditional sense) is opposite and the field rotates in stationary coils.

I was looking at parts diagrams and it LOOKS like the armature spins on ours which makes it a generator - though I also heard it referred to as "brushless" and that cannot be the case with power generating as I understand it....

I think I should be able to get this thing re-wound - I just want to learn up on it in advance of going to find a shop so I know what I am asking for and getting back.

I think I would acquire a second unit and have it done so I could continue to ride - I am also thinking I might need to beef up the wiring a gauge or two if we increase the amp output.

John

No, the coils on ours is stationary. The odd thing on ours is that the field coil that traditionally on an alternator spins is also stationary, and is pulsed, and the spinning metal rotor stirs the magnetic field to simulate the spinning magnetic field. This is a little less efficient than an actual spinning field coil system, but eliminates the slip ring and brush system, which removes a point of wear, which means that other than oxidation and problems with connection points, in theory they could last forever (we know it's not true, but there are no typical wear parts). The problem is going to be that unlike an automotive system that has air moving through it to cool it, these are sealed systems, so cooling is by nothing more than heat conduction to the frame of the engine and such. That's what has made getting one rewound so difficult so far. The reason the XJ has the extra capacity that it does is that it actually has the spinning field coil system, with the requisite slip ring and brush system and the wear that goes with it. But I think it is about an extra 10% or a little bit more that it gets capacity wise. Of course they are a little hard to find being that they are a one year bike.

[ManagerMike]

I made this inquiry directly to the owner/operator of the electrical repair shop that repairs and rebuilds DC starters, alternators and generators which I have been using at work for almost seven years now, and he claimed that while it may be possible to increase the current capacity slightly, it would be cost prohibitive and not worth it for what little gain that may be achieved.

[jwhughes3]

thanks all

I will live with it as is and see how Cy's conversion goes.

John

[b.walker5]

I've had one re-wound years ago, after burning it out with heated handgrips that went ballistic.

The shop did manage some extra turns on the windings for a small increase in output, and it did charge quicker after that. Dont know what the figures were as I've never measured it. Didnt cost any extra than a standard rewind did, all they did was add a bit of extra wire and maybe 5 minutes extra time.

Dont remember way the actual cost was but I know it was cheaper than a replacement stator.

In fact, Ive had two done. I had one melt down in my old XS750 as well.

[natemoen]

The reason the XJ has the extra capacity that it does is that it actually has the spinning field coil system, with the requisite slip ring and brush system and the wear that goes with it. But I think it is about an extra 10% or a little bit more that it gets capacity wise. Of course they are a little hard to find being that they are a one year bike.

Yeah, you go from 24 amps on an XS to 26 amps an XJ. You get more available amps from switching to all led lamps than switching alts.

[jwhughes3]

Houston, we have a problem....

All this "amp saving" reminds me of the scenes from Apollo 13 when they are trying to figure a way to start up the thing without exceeding the amperage limit.

I did switch to an LED tailight so that is one bit of savings - I am considering swapping the turn signals to LEDs to run as running lights with red lenses in the back end - anything to be more visible - I think giving up self cancelling is worth it.

Now to find the thread on the right flasher for LEDs!


John

[natemoen]

A 2 prong electronic flasher.

[crazy steve]

Yeah, you go from 24 amps on an XS to 26 amps an XJ. You get more available amps from switching to all led lamps than switching alts.

The XS alternator isn't that good; it's only rated at 20 amps...

This design is inherently ineffecient, so it doesn't respond to a rewind as well as a conventional design would. And Yamaha had to make some compromises in the design to allow it to work in this application, all of which don't help. Rewinding for higher current can be done, but that will reduce the voltage output if you go for more than a small increase in amps, so it's a bit of a 'catch 22' deal.

If you're looking for a serious increase in output, TCs' car alternator mod is the viable solution.

[natemoen]

The XS alternator isn't that good; it's only rated at 20 amps...

Interesting, I have always read 24 here. Good to know.

[crazy steve]

That's right out of the service manual; 14V/20A @ 5K rpm. You might see a bit more under certain conditions, but that's the rating. Trying to squeeze more out of it will shorten its life.