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#15
by
jtanguay
on 12 Nov, 2009 00:52
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from more reading, i found that the more intense the magnetic field on the rotor, the higher the amp output... if thats true, then all one needs to do is get some stronger magnets on the rotor. that would increase the efficiency by a lot (the alternator wouldn't need to be spun as fast to create the same output; let the permanent magnet do all the work
)
one other issue i've been thinking about is the heat output even when the alternator wasn't charging, but still spinning. i'm not an expert on a/c (yet) but would connecting all 3 phases create a continuous loop and drastically reduce or even eliminate the heat output? i'd say use very heavy duty relay's to do the switching, but they aren't too efficient, and expensive vs MOSFET's which are just a bit more complex set up.
the idea i have, is to get a few mosfets and parallel the output to boost the amperage. some testing would definitely need to be done though. i bet a PMA kit could be sold for about $200. it would include the rotor with magnets and a controller box mounted somewhere cool (controller box would have the mosfets and diodes-more diodes=more efficiency)
oh yea one other 'side' benefit of the PMA is that you can start charging WITHOUT a power source. yes thats right! your battery could be bone dead, but if you can bump start it, then you're rockin'
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#16
by
truckinwagen
on 12 Nov, 2009 01:44
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if you can make a kit for $200-ish, and somehow show the power output (in watts) and power draw to produce it( in HP) I would definitely buy one(or two, who knows)
but I would like to see real numbers about power generated and power draw to prove that they are more efficient first.
-Owen
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#17
by
745 turbogreasel
on 12 Nov, 2009 02:44
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Aparently, all you need to do is corner a prius, and rip out its flywheel...
Hybrid Synergy Drive
The Electric Motor
The compact, lightweight high-efficiency AC permanent magnet synchronous motor does not use brushes like a direct current motor, so it offers superior durability. And since the permanent magnet needs no electricity to create a magnetic field, it is much more energy efficient. The motor functions as a generator during regenerative braking, converting the vehicle’s kinetic energy into electricity to charge the battery.
The Battery
The sealed nickel-metal hydride battery, designed especially for electric vehicles, offers high power density, light weight, and long life. Its performance has been further boosted for the Toyota Hybrid System, with output per unit capacity more than triple that of most electric vehicles. This allows the battery to provide a huge surge of electricity to the motor precisely when it’s needed for all-out acceleration.
Generator
The high-efficiency AC permanent magnet synchronous generator produces electricity to charge the batteries and power the motor. By controlling the generator speed, the power split device functions like a continuously variable transmission. The generator also functions as a starter for the engine.
Power Split Device
The power split device uses planetary gears that allocate engine output between the drive wheels and the generator. By controlling the generator speed, the power split device also functions like a continuously variable transmission. Engine output is directed inward to the planetary carrier of the power split device and outward through the sun gears to the generator and through the ring gear to the motor and the wheels.
Regenerative Braking System
When decelerating or braking, the motor acts as a generator, recovering kinetic energy from the wheels, converting it into electricity and storing it in the battery. It’s an ideal energy-saving system for stop-and-go city driving. When the driver applies the brakes, both the hydraulic brakes and the regenerative brakes are used, with the priority going to the regenerative braking system to maximise energy recovery.
Inverter
The inverter changes the battery’s direct current into alternating current to drive the motor and turns the generator’s alternating current output into direct current to charge the battery. It also varies the frequency of the current, depending on motor rpm to maximise efficiency. The inverter unit is water cooled for improved reliability.
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#18
by
burnt_servo
on 12 Nov, 2009 08:48
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the use of genertors isn't that old , around the late 50's early 60's is when the use of alternators took over .
i haven't seen a genertor with a electromagnet .
what if in the " new " generator , with the use of some electromagnets , the inverse of the magnetic feild was created in an attempt to cancel out the fixed magnets feild in an attempt to control the amount of current produced ?
if your looking for a alternator with very few moving parts , i believe cat uses 2 fixed electromagnets , with a moving rotor between them to create " pulses " which creates the current .
no brushes to wear out ever .
or here is an idea , use an exhaust driven turbine ( aka turbo ) but with the compressor side removed and replaced with a " new " generator .
then use the waste gate to control the current output.
this would free up even more horsepower from the motor and make things more effecient since it would be using energy that is normally wasted out the exhaust .
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#19
by
jtanguay
on 12 Nov, 2009 10:49
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the use of genertors isn't that old , around the late 50's early 60's is when the use of alternators took over .
i haven't seen a genertor with a electromagnet .
what if in the " new " generator , with the use of some electromagnets , the inverse of the magnetic feild was created in an attempt to cancel out the fixed magnets feild in an attempt to control the amount of current produced ?
if your looking for a alternator with very few moving parts , i believe cat uses 2 fixed electromagnets , with a moving rotor between them to create " pulses " which creates the current .
no brushes to wear out ever .
or here is an idea , use an exhaust driven turbine ( aka turbo ) but with the compressor side removed and replaced with a " new " generator .
then use the waste gate to control the current output.
this would free up even more horsepower from the motor and make things more effecient since it would be using energy that is normally wasted out the exhaust .
the old way of regulating the generator's power seems a bit archaic to say the least, but definitely a simple option. i've been thinking about using the slide generator system on the suspension
about cancelling out the field... thats what i'm trying to do with connecting all 3 phases so that the motion of the rotor creates a field that helps it spin to eliminate resistance. i'm still thinking that the mosfet route is the best one to take, but not 100% sure yet as our cars do require large amounts of amps... one idea i had was to make the poor mans toroid by taking an old stator and winding it with more wire and using that wire as the primary (wound to the same spec as the stator with 3 phases) then just vary the field as required to create the current
but maybe using mosfets can bypass that step?
as for the turbo... i've really been thinking of adding permanent magnets and a stator to the turbo center section. it would be quite difficult though, and would definitely need balancing after adding the magnets. the magnets would also have to be pretty small as to not affect the weight too much. best part, is that you could have the turbo pre-spin to eliminate turbo lag or make it into a supercharger. that is a very ambitious idea though
and about the prius... very interesting idea! i've read about companies putting the starter right into the flywheel... good stuff! i'm a huge fan of a/c power so i'm digging that setup. now adding some permanent magnets to the flywheel and adding a stator would really make the poor mans hybrid. things would get pretty tight in the bell housing though. but then why not just go all the way and switch to electro-magnet clutch? the faster the engine spins, the more the clutch grabs? ah too many ideas...
one last one i had was to use 2 3-phase motors to create a continuously variable transmission. each phase on the drive motor would be independant from eachother, but a microcontroller could control each separately. this means that once the motor is fully spinning, only one coil would need to be energized to maintain speed. when accelerating, more phases are engaged to increase torque. its a little advanced, but i think it could work. and best of all, you could stash maybe 6 batteries in the trunk and have a really cool hybrid. and hey no more transmission!
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#20
by
dieselweasel
on 14 Nov, 2009 14:17
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Connecting the alternator's three phases together would create a short circuit. Each phase has a different potential at a different time depending on the field position.
FWIW, I know that motorcycles and other small engines use PMAs and I have seen them as charge alternators on some Generac gensets with 12V electrical systems.
I'm not convinced that there's much benefit to a PMA though. True, a small amount of current is saved due to not having a field to energize. Also nice not having brushes (as someone else noted, many heavy duty alternators are brushless). But I would think a PMA would require just as much HP to turn as would a conventional alternator. The stronger the magnetic field created by the rotor, the more hp required to turn it.
Don't get me wrong, I'm not knocking your idea...just need more proof that 2-3 mpg could be saved?
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#21
by
jtanguay
on 14 Nov, 2009 23:59
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Connecting the alternator's three phases together would create a short circuit. Each phase has a different potential at a different time depending on the field position.
FWIW, I know that motorcycles and other small engines use PMAs and I have seen them as charge alternators on some Generac gensets with 12V electrical systems.
I'm not convinced that there's much benefit to a PMA though. True, a small amount of current is saved due to not having a field to energize. Also nice not having brushes (as someone else noted, many heavy duty alternators are brushless). But I would think a PMA would require just as much HP to turn as would a conventional alternator. The stronger the magnetic field created by the rotor, the more hp required to turn it.
Don't get me wrong, I'm not knocking your idea...just need more proof that 2-3 mpg could be saved?
connecting all 3 legs together on an a/c motor isn't the same as doing it with a DC motor. the power should pulse back and forth through the coils and hopefully cancel out any resistance.
as for the efficiency, just think of getting rid of that claw rotor. its just a big mass of steel rotating at around 3:1 engine speeds. so if you rev it up to 6k rpm then the alternator rotor is spinning at 18,000 rpm! (lets not even get into the efficiency loss of trying to energize a DC field at these rpm's...) no wonder the 1.9's had the crank nose issue. i personally would use a plastic or epoxy to create the rotor and embed the magnets in it. true that the stronger the magnetic field, the more resistance created, but the power output is proportional to this change... so if you achieve your power goal at lower rotating speeds, then the alternator will be running smoother and with less heat if an appropriate charge controller is used (higher rotating speeds, the lower the frequency) and don't forget that the higher the amperage draw, the stronger the magnetic field required, which severely reduces the efficiency of the alternator.
even running a new style diode pack should net you a 10% increase or more efficiency... the diodes they put in alternators aren't the greatest. the more diodes you use per leg, the less resistance... this could be a feature of the charge controller. special fast recovery diodes can be bought for about 50 cents each. 6 on each leg (3 pos 3 neg) for 18 diodes at 9 bucks... there's your first efficiency 'upgrade'
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#22
by
jtanguay
on 15 Nov, 2009 13:28
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i've also been thinking about utilizing the high voltage out of an alternator. that would help keep the heat output low. best of all, it wouldn't be hard to convert a mechanical diesel over to high voltage a/c - about 400-600 volts at 1.5 amps or so each leg, so an output of over 2000 watts should be easily achieved, 500 more watts than a 120 amp alternator, and less waste due to heat, etc.
another reason to go high voltage is that the electronic equipment for high volts is much cheaper than for high amps. of course certain parts will still use low voltage DC such as power locks, radio, cluster, but with much less amps to increase efficiency. things like the rad fan, heater blower, and headlamps could make use of the high efficiency of a/c electricity. this type of changeover would be pretty intense, but the benefits are huge. just think of switching to a high rpm a/c motor to drive the water pump. low flow when cold, and high flow for performance driving. want to have an afterrun cooling effect? get an inverter. its proven that dc inverted to a/c is more efficient than simply using dc. a simple 3 phase pwm could be made to control the motors... ah the possibilities are seemingly endless.
and for those who are scared of high volts, don't be. just use caution when working with it at all times. the system will only be producing the high volts when the car is on, and the watts will be similar to a regular car anyway. any leads should be insulated as well.
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#23
by
dieselweasel
on 15 Nov, 2009 14:26
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I'm still thinking that you're going to have a problem by connecting the 3 stator phases together. Doing so would create a very low resistance, which would cause a great amount of current to flow in the stator. The magnetic field caused by this stator current is going to oppose the magnetic field of the rotor. This electrical loading will try to decelerate the rotor shaft, although the amount of heat generated in the stator would likely cause it to melt before long.
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#24
by
jtanguay
on 16 Nov, 2009 13:59
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I'm still thinking that you're going to have a problem by connecting the 3 stator phases together. Doing so would create a very low resistance, which would cause a great amount of current to flow in the stator. The magnetic field caused by this stator current is going to oppose the magnetic field of the rotor. This electrical loading will try to decelerate the rotor shaft, although the amount of heat generated in the stator would likely cause it to melt before long.
you might be right, but thats why i want to do some testing
i might buy a cheap alternator and try some things out. i'm hoping that without an electrical load, the amps will be reduced to keep heat down. but who knows.. maybe just leaving the legs disconnected won't really affect anything? i'd really want to keep it simple...
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#25
by
macka
on 18 Nov, 2009 18:06
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I'm still thinking that you're going to have a problem by connecting the 3 stator phases together. Doing so would create a very low resistance, which would cause a great amount of current to flow in the stator. The magnetic field caused by this stator current is going to oppose the magnetic field of the rotor. This electrical loading will try to decelerate the rotor shaft, although the amount of heat generated in the stator would likely cause it to melt before long.
you might be right, but thats why i want to do some testing i might buy a cheap alternator and try some things out. i'm hoping that without an electrical load, the amps will be reduced to keep heat down. but who knows.. maybe just leaving the legs disconnected won't really affect anything? i'd really want to keep it simple...
one of the Japanese 80's alts would be a cheap donor
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#26
by
jtanguay
on 19 Nov, 2009 11:03
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here's a cool experiment which demonstrates my idea for an electromechanical transmission:
Experiment: electric motor, easy to implement.as you see, it's sort of like in a pulsed configuration. as the contacts are closer together, the speed of the rotor is increased, and torque is decreased. is this not the basis of a regular transmission? and i would estimate losses to be less than 1% if properly controlled. but the rotor would be permanent magnets, and the stator would be wound coils independant from eachother, to increase torque on demand or increase speed. a perfect tri-divided coil will give maximum torque while only one coil will give maximum speed.
just thought i'd throw that out there...
but i'm still thinking for a way to use the flywheel as the alternator/starter though!!! the only thing i can think of is to have the flywheel have machined recesses and epoxy the magnets in them... then drill portions of the bellhousing out to insert coils at 120 degree's apart for a 3 phase system. just think... if the motor could deliver up to 5 hp, you could theoretically turn off the motor at a stop light like a hybrid, and then 'smoothly'
take off and the engine starts back up (for those of us with a good running diesel of course
)
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#27
by
maxfax
on 21 Nov, 2009 21:01
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That sparked something from memory, That's exactly how the output was adjusted on the old generators with a cut-out.... You moved the 2 brushes closer or futher apart.... I think the brush positioning was how starter generators would work come to think of it.. The start brushes were further apart than the generator brushes..
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#28
by
jtanguay
on 21 Nov, 2009 23:53
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That sparked something from memory, That's exactly how the output was adjusted on the old generators with a cut-out.... You moved the 2 brushes closer or futher apart.... I think the brush positioning was how starter generators would work come to think of it.. The start brushes were further apart than the generator brushes..
hmmm i wonder if an alternator would be capable of starting the engine? the ratio is pretty huge so the alt would need to put out a lot of torque... but essentially putting the brushes closer together make the motor run with less 'phase' and in turn achieves a higher speed... really good stuff to know! but then we're getting into John Bedini stuff though
i've also thought of using the high speed capability to help spool up turbo's for reduced lag, and even to siphon off power from them. could even use their own power generation to power a magnetic float bearing which would be way better than even ball bearing. at lower speeds, 120 degree phases are required for maximum torque, and after that you can just run off one phase to get some crazy rpm's
the more i learn about 3 phase motors and how they work... its a wonder that people aren't just building their own. they are one of the key ingredients to an electric car as well as the battery's. most people probably wouldn't touch an electric conversion with a ten foot pole simply because of the battery issue. but some
new technology (from John Bedini) is now out, and provides the perfect charging system to re-condition batteries and give more life to batteries for extended range. the system uses radiant energy to charge batteries. you can also pick up old, previously thought 'dead' batteries and revive them to really cut costs...
most people will say to use ferrite for the stator, but i don't really think its a requirement. i'm of the belief that aluminum would be a great material for the stator, as the only reason to not use it, is that aluminum does not hold a magnetic force. it will conduct a magnetic force like crazy though!
ah so many ideas...
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#29
by
maxfax
on 22 Nov, 2009 00:27
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hmmm i wonder if an alternator would be capable of starting the engine?
Not saying it's impossible, but definitely not easy.. THe majority of engines that used a starter generator were very low compression single cylinder engines.. I'd bet nothing much over 8:1.. Alot of the larger displacement engines had to have a compression release to be able to crank them fast enough to start... And still everything had to be pretty healthy as far as the starting system to get em to go..
Now taking your idea of mounting magents on the flywheel coupled with a compression release one might be able to pull it off... The compresion release would be the trickiest part..
THe automatic releases would hold the exhaust valve open slightly and be controlled by centifugal force.. When the rpms started to increase from the engine firing the weights would fly and allow the exhaust valve to close completely.. Some older engines (especially big old diesels) would have some variety of manual release.. Cat had a lever connected to I think the exhaust push rods that woudl crack the valves.. Old Case engines simply had a small petcock in the cylinder head that would be opened or closed.. (It's a challenege to get em all closed fast enough when it starts to fire!)
ah so many ideas...
So true.. Gets me in trouble on a daily basis...