Standard alternator or stator

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slociviccoupe

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Im more than likely going to use the compact 45a denso alt. But it woukd be nice to run the outboard stator and flywheel as a crank pulley for no belts. Thats the only reason. And the yamaha 225 outboard looking at for stator is in the same opperating range as the subaru.

Just saying technology is advancing. We dont have to be stuck with it has worked for the last 20 years so have to use it. If one could turn their normal crank pulley into a mag cup and mount a stator with no drive belt then i see that as a win win situation. And especially since the voltage regulation can be done very efficiently .

Just as a test have you ever turned an alternator on and see how much it drags an engine down. . I have a 13hp honda turning a denso 65a alternator from a honda s2000 and switching on the alternator is enough to drag the engine down. I guess one could apply variable field voltage using a controller or the engine ecu. Lots of car manufacturers do this.
 

Dan Thomas

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Just as a test have you ever turned an alternator on and see how much it drags an engine down. . I have a 13hp honda turning a denso 65a alternator from a honda s2000 and switching on the alternator is enough to drag the engine down. I guess one could apply variable field voltage using a controller or the engine ecu. Lots of car manufacturers do this.
65 amps at 14 volts is 910 watts, or 1.2 HP, plus a little more for losses. On a 13 HP motor you'll notice that. Not so much on larger engines, and especially since drawing max alternator capacity is a rare thing.
 

Geraldc

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65 amps at 14 volts is 910 watts, or 1.2 HP, plus a little more for losses. On a 13 HP motor you'll notice that. Not so much on larger engines, and especially since drawing max alternator capacity is a rare thing.
I watched a video yesterday that said an alternator runs at 50% efficiency.
The rest is heat loss. So 65 amps would be nearer to 2 hp.
 

Daleandee

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An alternator is a very high reliability device.

I use generators on my antique trucks and they are a PITA. Gotta magnitize them, then keep the commutator clean, then brushes wear/springs lose tension, undercutting mica is always fun. Or mount alternator. Run 1 wire to to the bus, enjoy.
Alternators are the way to go but I'm very satisfied with the Dynamo I use as it has been reliable and trouble free and they do not have the shortcomings of a generator i.e. don't need the magnetism trick & no brushes or springs to wear out. Only need to keep them clean and cool. Might need a bearing every dozen years or so. One of the biggest advantages to a Dynamo is that it doesn't need a power source to energize the coil.

I remember the first time I seen my dad magnetize a generator. I was a little fella and I had to know what he was doing and why. I didn't understand it at the time but it sure was an interesting procedure.

As far as the GM one wire alternators ... had a Toyota that needed an alternator and the one that was called for was out of my low rent budget at the time. GM to the rescue. Did the same thing on an old 1956 Chevy 3200 pickup with a 235 CID engine in it. Got tired of fighting with the generator and again a GM one wire alternator came to the rescue!
 

BJC

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I watched a video yesterday that said an alternator runs at 50% efficiency.
The rest is heat loss. So 65 amps would be nearer to 2 hp.
For the curious: utility scale generators have much better windings and cores in the stator (typically water cooled, but occasionally hydrogen cooled) than automobile / aircraft generators, as well as better / denser field windings (typically hydrogen cooled). Typical efficiencies exceed 99%.


BJC
 

pfarber

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Alternators are the way to go but I'm very satisfied with the Dynamo I use as it has been reliable and trouble free and they do not have the shortcomings of a generator i.e. don't need the magnetism trick & no brushes or springs to wear out. Only need to keep them clean and cool. Might need a bearing every dozen years or so. One of the biggest advantages to a Dynamo is that it doesn't need a power source to energize the coil.

I remember the first time I seen my dad magnetize a generator. I was a little fella and I had to know what he was doing and why. I didn't understand it at the time but it sure was an interesting procedure.

As far as the GM one wire alternators ... had a Toyota that needed an alternator and the one that was called for was out of my low rent budget at the time. GM to the rescue. Did the same thing on an old 1956 Chevy 3200 pickup with a 235 CID engine in it. Got tired of fighting with the generator and again a GM one wire alternator came to the rescue!
You many not realize this but one wire alternators are self exciting. So you get all the goodness of a Dynamo with the light weight of the alternators.


24V 40A $109

Save that weight, yo.
 

Daleandee

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You many not realize this but one wire alternators are self exciting. So you get all the goodness of a Dynamo with the light weight of the alternators.
Yes I did know that as I've posted about installing a couple of them before. But going with one of them means I gotta go back to the brushes & other parts wearing out (albeit they are easy enough to rebuild and kits are readily available). I don't recall the weight of the GM alternator but the dynamo is very light (4 lbs with the regulator). Besides all that I don't have the physical room for that big old honkin' GM alternator.

Thanks but I'm good!
 

akwrencher

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Those old 12si alternators are great for cheep power, but lightweight isn't one of its selling points. bet it weighs ten lbs, or close to it.
 

TFF

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You need the voltage regulator but a little Denso will be hard to beat. It will weigh a little more but the plus of a regulator is you can turn it off. Way more power available and mor than likely you could go through two engines before going through the alternator. Plus you can go to the auto parts store and grab something that will work just about anywhere. Nothing wrong with the little mower power dynamo . The guy building the GeeBee R2 is putting one on his R985 pretty much duplicating the installation on his Yak M-14 engine. Of course not running anything more than radios of sorts. Not going IFR or running EFI.
 
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