Has anyone seen or heard or replicated the Stephen Kundel motor? it really seems like a working solution!! Hurrah! Check out all the videos including the replication project.
http://www.kundelmotor.com (http://www.kundelmotor.com)
Very interesting motor. It demonstrates a working motor (very important, as most other motors claim to run but have never been seen running by a live person willing to give their testimony to the public), and a good way to extract motion from magnets (while using very little power). The motor is not a self starter, but requires a spin from the hand to start. The motor has good speed despite the moving part (moving parts can be justified in a motor as this motor demonstrates it's speed for certain applications). It is somewhat difficult to build because the ring magnets have to be cut to operate correctly and it requires quite a few magnets for the basic model to run. This model shows that timing to a magnetic motor is of great importance for performance. The magnetic angle of thrust between magnets is not ideal on this device, and results in weak torque which is partially derived from the linear action magnetic arm that shifts the magnets position which requires power. This model uses some attraction and repel from the magnets to aid in the creation of rotational torque in running the motor, without running into an opposing pole (preferred way to design a magnet motor). More magnet rings can be added to increase strength of motor, but also adds bulk to the moving magnetic arm. Overall, nicely done and well thought out. A good study in magnet motor design and has many good attributes. There are movies of replications by others at the Kundel web site.
very interesting design, however I don't know if it's anything to celebrate about just yet, the motors in the videos, even the replications, were not self-runners. It's a novel concept, however I don't know if it's an OU device, or just a unique PMM. It seems that the armatures don't move back and forth very far to get those fairly high rpms, so it could be possible to mechanically oscillate, or generate the power to oscillate the device. 30 volts at .4 amps (12W) on the australian replication, to run it, but what's the output?
I also noticed that it was fairly low torque (he slowed it almost to a stop with his fingers). So mechanical total power isn't all that astounding.
Quote from: gn0stik on June 01, 2006, 03:38:57 PM
very interesting design, however I don't know if it's anything to celebrate about just yet, the motors in the videos, even the replications, were not self-runners. It's a novel concept, however I don't know if it's an OU device, or just a unique PMM. It seems that the armatures don't move back and forth very far to get those fairly high rpms, so it could be possible to mechanically oscillate, or generate the power to oscillate the device. 30 volts at .4 amps (12W) on the australian replication, to run it, but what's the output?
I also noticed that it was fairly low torque (he slowed it almost to a stop with his fingers). So mechanical total power isn't all that astounding.
Any ideas as to how he could increase the torque on the motor without adding bulk to the linear magnet arm?
My suggestion would be to add another whole motor running more magnets at a 90 degree rotation to the first motor, but still running on the same axle to add torque to the motor further around the rotation. Hopefully it would add more torque than electrical power used so it could be recovered with a small generator???
Well, without adding a flywheel, there's not much you can do... Adjusting the timing would be critical to torque, but aside from that, the only thing that would improve it, would be ensuring you are using the same strength of magnets on both the rotors and stators, and using bigger mags. neo n45-50 would be as strong as you can get.. Also, he's got too much mass on there already. You'd get the same rotational speed out of one rotor/stator setup as you would out of 3, but it's not really hurting anything the way it is.. Just more work to build. More mags does not necessarily mean more power. Larger mags however does.
However first things first, he needs to wind some coils and attach some mags to that shaft and see what kind of power he gets out of it with a low effiency generator. Then he can scale up the calculations to a higher efficiency setup.
for e.g. "If I'm getting (eout) power with a generator that is (x%) efficient, my (eout) with a motor that is (y%) efficient would be z.."
I would think that if the magnets were bigger around, say like 12 inches or larger, that the torque down at the axle would be increased by the larger magnet ring turning it providing more leverage.
I agree that a small generator should be attached to see what he can get out of it. I am at the same point on my motor. Stepper motors are a good choice for low rpm motors (see web page below), and small permanent magnet dc motors like RC car motors or toy motors are a good choice for higher rpm motors. Here is a web page that may be helpful to others needing to make a small cheap generator to test a motors output with a stepper motor.
http://www.c-realevents.demon.co.uk/steppers/stepmotor.htm (http://www.c-realevents.demon.co.uk/steppers/stepmotor.htm)
I really like what he (Kundel) is doing.
He is not showing a bunch of vague drawings and sketches.
He is not making a bunch of wild claims.
He is not talking about threats on his life.
He is not hiding behind a veil of secrecy.
He is not leading people on wild goose chases.
He is not selling "snake oil"
He is not asking for money.
He is building an interesting motor that actually rotates, and putting it out there for everyone to see.
Clearly this is not an "overunity" or PMM, and he doesn't claim it to be. It is innovative and functional, though, and I commend him on his approach of showing something actually working before making a bunch of wild claims. The concept of creating rotation from reciprocation (and vice-versa) without contact between the rotator and reciprocator is noteworthy itself.
I like this guys style.
Jake noticed the same thing I did about Kundel making no claims to OU. What he has done is given us another way to look at magnets and motors. I think we'll get this thing down once we have the right perspective. I'm pretty sure it will be a mechanical method of opening and closing the gate to go full circle. At least until we get slicker at manipulating fields.
I have assembled a basic Kundel motor to study the effect. (Without the actuator coil.) I assembled a sliding apparatus to hold the actuators and moved them back and forth with my hands. It pays to "feel" what magnets are doing.
What I have gathered from my plastic version is that the faster it goes, the less distance the actuator has to move. I would imagine that once a motor like this gets up to a certain speed, you would only need something like a vibration or sound wave or some other kind of micro-pulse to keep the actuator moving "in rythm" so to speak. Just using my hands, I have to start off moving it back and forth about an inch. After about 12-15 rotations, I only have to use the slightest movement to keep accelerating until it goes too fast for me to keep rhythm. Add a flywheel and there could be some decent torque in addition to high rpm's. Although I can appreciate the Sprain design, it seems to limit its rpm's by it's inherent design. The Kundel motor just wants to go faster!
We need something that starts off vibrating "big" as far as amplitude and low in frequency and then ends up "small" in amplitude and fast in frequency. I imagine a sound like the beginning of "THX" movies.
I'm thinking of hooking a speaker up to the actuator and slowly bending a low frequency note up in pitch until the motor max's out. Even if I have to kick start it to get it to the point where it will self accelerate off of about 20-30 hz. I know from running sound that you need way less wattage to run midrange speakers and tweeters that you do for the low freq subwoofers. Eventually, you could go supersonic in frequency and use a less and less energy in theory, right? So with a flywheel and possible "Supersonic" capabilities, the puppy might be able to rock the house!
Thoughts?
K~
Yes, I think the way he has it built, with the reed switches, it gives itself it's own upper limit. We take what we know about resonance, and mechanical gating, and this thing could be fun. How to lower the reciprocating action once it gets up to speed though?
The reed switches may be helpful for startup, then disengaging once a "sonic" rpm has been reached. I'd rather just spin it up manually, then hit that bass note to take over.
If I had a "super speaker" that could go sub-sonic, it may even self start. Either that or I will have to lower the tolerances on this particular build.
**By the way folks...I didn't have to cut ring mags to get this to work. I've been recycling the same old neos for most of the designs I've worked on.***
Quote from: konduct on June 02, 2006, 09:51:12 AM
Jake noticed the same thing I did about Kundel making no claims to OU. What he has done is given us another way to look at magnets and motors. I think we'll get this thing down once we have the right perspective. I'm pretty sure it will be a mechanical method of opening and closing the gate to go full circle. At least until we get slicker at manipulating fields.
I have assembled a basic Kundel motor to study the effect. (Without the actuator coil.) I assembled a sliding apparatus to hold the actuators and moved them back and forth with my hands. It pays to "feel" what magnets are doing.
What I have gathered from my plastic version is that the faster it goes, the less distance the actuator has to move. I would imagine that once a motor like this gets up to a certain speed, you would only need something like a vibration or sound wave or some other kind of micro-pulse to keep the actuator moving "in rythm" so to speak. Just using my hands, I have to start off moving it back and forth about an inch. After about 12-15 rotations, I only have to use the slightest movement to keep accelerating until it goes too fast for me to keep rhythm. Add a flywheel and there could be some decent torque in addition to high rpm's. Although I can appreciate the Sprain design, it seems to limit its rpm's by it's inherent design. The Kundel motor just wants to go faster!
We need something that starts off vibrating "big" as far as amplitude and low in frequency and then ends up "small" in amplitude and fast in frequency. I imagine a sound like the beginning of "THX" movies.
I'm thinking of hooking a speaker up to the actuator and slowly bending a low frequency note up in pitch until the motor max's out. Even if I have to kick start it to get it to the point where it will self accelerate off of about 20-30 hz. I know from running sound that you need way less wattage to run midrange speakers and tweeters that you do for the low freq subwoofers. Eventually, you could go supersonic in frequency and use a less and less energy in theory, right? So with a flywheel and possible "Supersonic" capabilities, the puppy might be able to rock the house!
Thoughts?
K~
What this motor demonstrates is a way to run a magnet motor that was said to be "not useful" because it has a moving part. It shows that what was once thought of not practical to do, has now become useful towards acheiving a motor that extracts motion from magnets using very little power. That is what I have done with my motor too. Electric motors are stronger, but you can still achieve motion with less power using magnets in your motors.
Is there a way to show a design without the concern that someone will take it and patent it and call it theirs?
Liberty
In the US they use a provisional patent as a way to date your idea while you decide whether to patent it. It becomes the official date of recod in disputes, I think. If you really think you are on to something you should file for provisional at least. I think you have one year of "protection" with it, and it is relatively inexpensive.
Quote from: jake on June 02, 2006, 11:29:53 AM
In the US they use a provisional patent as a way to date your idea while you decide whether to patent it. It becomes the official date of recod in disputes, I think. If you really think you are on to something you should file for provisional at least. I think you have one year of "protection" with it, and it is relatively inexpensive.
Thanks Jake,
I'll look into it.
Liberty
Ok I noticed something interesting about his motor. I don't know if anyone else looked at the pics on the front page of his web site, or if you just looked at the movies and animations. The pics show something that is more revealing than the movies do. Take a close look at the input power under load/no load conditions. This gives you a HUGE clue as to why he uses a voice coil instead of some other electromechanical device. It actually draws LESS power under load than it does without one, think about that one for a minute. This guy is brilliant. A voice coil does EXACTLY the same amount of work regardless of load. So I wrote him an email to confirm it. He's very careful about making any claims as to the power output of his device. That I'm sure will remain unchanged, and I for one commend him for it. IF his device is OU(and I'm not saying that it is), that will kill it quicker than anything, as those types of claims have killed every OU device to come down the pike thus far. We will probably NEVER see output readings. However his input readings are very interesting. I'm going to build one regardless of whether or not it is OU. I just think it will be a great learning experience, and fun to boot. Besides, it's the only way to find out.
Quote from: MeHey, I just found your web site for the Kundel Motor.. Very interesting design. Couple of questions however, how can it possibly draw less power UNDER LOAD than not? That?s mind boggling. Also could it be possible to power it via DC as opposed to AC? I?m assuming the voice coil is critical, no servos or other linear devices would work and have the same effect under load? I don?t know anything about voice coils so I don?t know if they can be powered via DC. I assume so since boom boxes have speakers in them, and they are DC. Unless they rectify the VDC to ADC. I?m thinking about starting a motor project of my own after seeing this. Also, what kind of ouput power are you seeing? How efficient is this type of electric motor verses a typical electric coil/mag motor?
Rich
Quote from: Stephen Kundel
The load is not directly connected to the solenoid. The solenoid is pulling in or pushing out, it does the exact same work (pushing / pulling the reciprocating magnets) every reciprocation load or no load. The load is between the reciprocating magnets and the rotor magnets attached to the axle. Torque is comparable to a 30+ watt fan motor, but the second prototype is not a good test bed, was built for determining magnet spacing (reciprocators and rotors), and the voice coil's air gap is massive. Starting third prototype for testing.
http://en.wikibooks.org/wiki/Engineering_Acoustics/Moving_Coil_Loudspeaker
http://electronics.howstuffworks.com/speaker5.htm
Sincerely
Stephen Kundel
Quote from: gn0stik on June 02, 2006, 10:12:14 PM
Ok I noticed something interesting about his motor. I don't know if anyone else looked at the pics on the front page of his web site, or if you just looked at the movies and animations. The pics show something that is more revealing than the movies do. Take a close look at the input power under load/no load conditions. This gives you a HUGE clue as to why he uses a voice coil instead of some other electromechanical device. It actually draws LESS power under load than it does without one, think about that one for a minute. This guy is brilliant. A voice coil does EXACTLY the same amount of work regardless of load. So I wrote him an email to confirm it. He's very careful about making any claims as to the power output of his device. That I'm sure will remain unchanged, and I for one commend him for it. IF his device is OU(and I'm not saying that it is), that will kill it quicker than anything, as those types of claims have killed every OU device to come down the pike thus far. We will probably NEVER see output readings. However his input readings are very interesting. I'm going to build one regardless of whether or not it is OU. I just think it will be a great learning experience, and fun to boot. Besides, it's the only way to find out.
Quote from: MeHey, I just found your web site for the Kundel Motor.. Very interesting design. Couple of questions however, how can it possibly draw less power UNDER LOAD than not? That?s mind boggling. Also could it be possible to power it via DC as opposed to AC? I?m assuming the voice coil is critical, no servos or other linear devices would work and have the same effect under load? I don?t know anything about voice coils so I don?t know if they can be powered via DC. I assume so since boom boxes have speakers in them, and they are DC. Unless they rectify the VDC to ADC. I?m thinking about starting a motor project of my own after seeing this. Also, what kind of ouput power are you seeing? How efficient is this type of electric motor verses a typical electric coil/mag motor?
Rich
Quote from: Stephen Kundel
The load is not directly connected to the solenoid. The solenoid is pulling in or pushing out, it does the exact same work (pushing / pulling the reciprocating magnets) every reciprocation load or no load. The load is between the reciprocating magnets and the rotor magnets attached to the axle. Torque is comparable to a 30+ watt fan motor, but the second prototype is not a good test bed, was built for determining magnet spacing (reciprocators and rotors), and the voice coil's air gap is massive. Starting third prototype for testing.
http://en.wikibooks.org/wiki/Engineering_Acoustics/Moving_Coil_Loudspeaker
http://electronics.howstuffworks.com/speaker5.htm
Sincerely
Stephen Kundel
I think Stephen Kundel uses a voice coil because it is a much faster device and uses less power because of the magnetic assist to the voice coil, than a solenoid for the puposes of his motor. Also, he only drives it one direction to save power consumption. 50% duty cycle. On this design, the faster that the motor goes, the less time the voice coil is turned on to drive the magnets into position.
I don't really care what kind of claims he makes, over unity or not, as that does not change the motor operation at all in my mind. I just focus on the ability of the invention rather than the character of the inventor and find the motor design interesting using magnets on a rotor and a stator. It has to use less power than a comparable electric motor of high efficiency for the amount of work accomplished per watt used, because of the use of magnets to assist in rotation is replacing electric power consumption that would occur in a standard electric motor. It is on the right path and idea to producing more power than it consumes in my opinion. Perhaps Stephen Kundel will put a small generator/alternator on his motor and compare power in to power out to answer the question for us.
Liberty
Well if you read closely you can do some research, we can get a horsepower rating from rpms and torque. Horsepower can then be converted to other output types. I'll look into it. Of course, any results I get will be speculative.
Thanks for the correction jake.
A 30w fan motor means 30 watts, right?
30/746 = 0.040 hp
0.040 hp @ 1800 rpm = 0.117 ft*lb or 1.4 in*lb.
Quote from: jake on June 03, 2006, 09:47:55 PM
A 30w fan motor means 30 watts, right?
30/746 = 0.040 hp
0.040 hp @ 1800 rpm = 0.117 ft*lb or 1.4 in*lb.
On Stephen Kundel's web site, the highest voltage rating in AC volts is 4.72 volts and the highest current in AC is .91A. The power calculation is P=IXE. AC power is about 4.3 watts.
Would this motor have the capability to self run with a 30 watt output?
On kundel?s web-site I reed about the use of a 60W fan blade !
S
dL
Quote from: jake on June 03, 2006, 09:47:55 PM
A 30w fan motor means 30 watts, right?
30/746 = 0.040 hp
0.040 hp @ 1800 rpm = 0.117 ft*lb or 1.4 in*lb.
Yeah, that's what I thought too, but.... I checked to be sure, and that's what I found. HP*746 is supposed to equal Watts. So I figured I was missing something or remembering it wrong. Apparently not.
However, your math is wrong too. 1200-1500 rpm was what the motors use so to figure torque at 1800 (the conservative figure for kundel's motor would be over optimistic for figuring torque for HIS motor, since he's comparing his to theirs) we need to figure torque from the sample motor rpms, not his.
0.040 hp @ 1200rpm = 0.175 ft. lb
0.040 hp @ 1500rpm = 0.140 ft. lb
So we apply those torque figures to his motor at 1800(his) rpm.
(1800 rpm * 0.175)/5252 = 0.059hp 0.059*746 = 44.014 Watts output
(1800 rpm * 0.140)/5252 = 0.048hp 0.048*746 = 35.80 Watts output
(2500 rpm * 0.175)/5252 = 0.083hp 0.083*746 = 61.91 Watts output - hmm lancaIV? blade doesn't mean much though.
(2500 rpm * 0.140)/5252 = 0.067hp 0.067*746 = 49.98 Watts output
now remember input was in the 3-5 Watt range.
So before conversion to electricity we have the potential to have a minimum of around 700% efficiency, and a max of about 1500%(rough guesstimate) Pretty huge range.
Of course conversion to electricity from hp will not be 100% efficient, so I don't wan't to imply it's actually going to out put that. That's just it's gross efficiency, so to speak. I think the actual numbers would probably be in the 40-60% conversion efficiency range, but I'm just guessing.
So Using those very non-scientific guesses, we're looking at anywhere from 17(lowest output *.4 for 40% conversion efficiency) Watts to 30 (highest * .6 for 60% conversion efficiency) Still pretty friggin impressive. 300 - 750% approximate efficiency after conversion losses, assuming conventional methods of conversion (EM).
Sorry for the mistake before... Please... correct these numbers too if I'm wrong.
Well, I think this motor MUST be measured with analog volt and amperemeters,
not with digital as there are fast pulses that can?t be measured by
this digital multimeter.
Also the torque is not very big and if it draws around 4 Watts of input power
the fan output power is probably just under 2 Watts.
Normal 30 Watts fan motors are also very inefficient and
as long as he does not measure the torque with a prony break under
a load, I guess this motor is pretty unefficient. It has very big magnet
airgaps and thus electrical to mechanical power conversion is low..
That the motor does not increase in input power under a load
just shows this inefficiency and it is just impedance matching in this
case and I want to see analog meter readings.
But the site is very nice made and also the motors and
the concept is clear understandable, that is very nice.
Also it might be usefull to use copper-graphite brushes in series
to drive the coils from a 12 Volts lead accid battery, this way the battery will
be reacharged due to the Newman sparking commutator effect and you could light up in
series an indescant lamp from the RF burst pulses...
and finally see, if more magnets on the motor need also more
or less input power..
We will see, at least this motor makes quite some noise
and might also have vibrational problems, so I don?t know how
long such a motor would last and might need much more
maintainance than a standard motor....
but interesting concept.
Quote from: gn0stik on June 04, 2006, 12:57:27 AM
Quote from: jake on June 03, 2006, 09:47:55 PM
A 30w fan motor means 30 watts, right?
30/746 = 0.040 hp
0.040 hp @ 1800 rpm = 0.117 ft*lb or 1.4 in*lb.
Yeah, that's what I thought too, but.... I checked to be sure, and that's what I found. HP*746 is supposed to equal Watts. So I figured I was missing something or remembering it wrong. Apparently not.
However, your math is wrong too. 1200-1500 rpm was what the motors use so to figure torque at 1800 (the conservative figure for kundel's motor would be over optimistic for figuring torque for HIS motor, since he's comparing his to theirs) we need to figure torque from the sample motor rpms, not his.
0.040 hp @ 1200rpm = 0.175 ft. lb
0.040 hp @ 1500rpm = 0.140 ft. lb
So we apply those torque figures to his motor at 1800(his) rpm.
(1800 rpm * 0.175)/5252 = 0.059hp 0.059*746 = 44.014 Watts output
(1800 rpm * 0.140)/5252 = 0.048hp 0.048*746 = 35.80 Watts output
(2500 rpm * 0.175)/5252 = 0.083hp 0.083*746 = 61.91 Watts output - hmm lancaIV? blade doesn't mean much though.
(2500 rpm * 0.140)/5252 = 0.067hp 0.067*746 = 49.98 Watts output
now remember input was in the 3-5 Watt range.
So before conversion to electricity we have the potential to have a minimum of around 700% efficiency, and a max of about 1500%(rough guesstimate) Pretty huge range.
Of course conversion to electricity from hp will not be 100% efficient, so I don't wan't to imply it's actually going to out put that. That's just it's gross efficiency, so to speak. I think the actual numbers would probably be in the 40-60% conversion efficiency range, but I'm just guessing.
So Using those very non-scientific guesses, we're looking at anywhere from 17(lowest output *.4 for 40% conversion efficiency) Watts to 30 (highest * .6 for 60% conversion efficiency) Still pretty friggin impressive. 300 - 750% approximate efficiency after conversion losses, assuming conventional methods of conversion (EM).
Sorry for the mistake before... Please... correct these numbers too if I'm wrong.
These are all very good approximations, but to really find out under real operating conditions of the motor itself, a small alternator/generator should be attached to determine what power output can actually be obtained. Then we will know without a doubt whether it can self power or not. The numbers look very encouraging with such a wide window for the probability of more power out than in.
However, the torque curve is unknown on this motor. (I suspect very low torque at high RPM range, and higher torque at lower RPM range, because of the way the motor slowed down when fan load was applied). This could affect generator/alternator power production, that the numbers may not reveal to us in our calculations. It will for this reason, be important to carefully match the alternator/generator used for test, to this motors' RPM and torque curve for a test that makes the most of this motor's capability, to be a fair test.
-----------
Quote from: hartiberlin on June 04, 2006, 11:02:15 AM
Well, I think this motor MUST be measured with analog volt and amperemeters,
not with digital as there are fast pulses that can?t be measured by
this digital multimeter.
Also the torque is not very big and if it draws around 4 Watts of input power
the fan output power is probably just under 2 Watts.
Normal 30 Watts fan motors are also very inefficient and
as long as he does not measure the torque with a prony break under
a load, I guess this motor is pretty unefficient. It has very big magnet
airgaps and thus electrical to mechanical power conversion is low..
That the motor does not increase in input power under a load
just shows this inefficiency and it is just impedance matching in this
case and I want to see analog meter readings.
But the site is very nice made and also the motors and
the concept is clear understandable, that is very nice.
Also it might be usefull to use copper-graphite brushes in series
to drive the coils from a 12 Volts lead accid battery, this way the battery will
be reacharged due to the Newman sparking commutator effect and you could light up in
series an indescant lamp from the RF burst pulses...
and finally see, if more magnets on the motor need also more
or less input power..
We will see, at least this motor makes quite some noise
and might also have vibrational problems, so I don?t know how
long such a motor would last and might need much more
maintainance than a standard motor....
but interesting concept.
The power consumption not going up with the load is more of a function of the design of the motor (taking advantage of the rotational power from magnets) than inefficency. The voice coil is positioning the magnet for the next 1/2 cycle. It contributes some to torque by pushing into the repelling field of the magnet, but because the magnets are trying to align themselves constantly, the rotational power largely comes from the magnets and therefore does not translate back directly into electrical load from a physical load being applied.
Liberty
Quote from: hartiberlin on June 04, 2006, 11:02:15 AM
Well, I think this motor MUST be measured with analog volt and amperemeters,
not with digital as there are fast pulses that can?t be measured by
this digital multimeter.
Also the torque is not very big and if it draws around 4 Watts of input power
the fan output power is probably just under 2 Watts.
Normal 30 Watts fan motors are also very inefficient and
as long as he does not measure the torque with a prony break under
a load, I guess this motor is pretty unefficient. It has very big magnet
airgaps and thus electrical to mechanical power conversion is low..
That the motor does not increase in input power under a load
just shows this inefficiency and it is just impedance matching in this
case and I want to see analog meter readings.
But the site is very nice made and also the motors and
the concept is clear understandable, that is very nice.
Also it might be usefull to use copper-graphite brushes in series
to drive the coils from a 12 Volts lead accid battery, this way the battery will
be reacharged due to the Newman sparking commutator effect and you could light up in
series an indescant lamp from the RF burst pulses...
and finally see, if more magnets on the motor need also more
or less input power..
We will see, at least this motor makes quite some noise
and might also have vibrational problems, so I don?t know how
long such a motor would last and might need much more
maintainance than a standard motor....
but interesting concept.
The figures we worked from are input power and what he estimated as torque. There were a lot of assumptions made in my calculations due to the lack of factual information we had to work with, but I believe that the math is sound. If our input power were more accurate, via use of an analog meter, that would be fine, but ultimately it wouldn't make that huge of a difference. To make this more accurate the analog meter on the input, a torque meter on the output, and a small alternator attached to the shaft with another analog meter on that are the only things that would give us real factual info.
This would give us true input power, true gross output power, and effective output power(based on the alternator used, this is variable). That is why the range on my calculations is so large, to allow for a lowest, and highest efficiency, based on the knowlege we have of the device.
Unless there is an error in the figures I'm sure it's output power is somehwere in the range I specified. If you can find a flaw, please let me know. I mean you must have a reason to believe the output power to be just under 2 watts, right? Unless you meant the actual fan motor from which he got the torque comparison. which would actually be:
A typical fan motor is about 60% efficient, let's give it the benefit of the doubt and say 66% that gives us a nice round output number.
So, it can't be this... because it would have around 20W output. As is typical for a fairly efficient fan motor.
If Kundel's motor had the same efficiency his output with 4W input would be 2.64W, and the numbers just don't support that.
Let's work it backwards...
2.64W/746 = 0.0036 hp
(0.0036 hp * 5252) / 1800 rpm= 0.0123 ft. lb torque Which is less than 1/100th of what he estimated. It just doesn't figure...
Can you help me figure out how you came up with your numbers?
Fans are very easy to turn,
you don?t need 20 Watts for this, you only have the low wind friction !
Until no prony brake measurements are made, these
above calculations are just speculations,
for instance if the normal 30 Watts fan motor
would only have a 20 to 30 % efficiency the
calculation would be quite different, also it is a question,
if the 30 Watt fan motor would also run at 30 Watts
input all the time or if the input is lower, but the motor
is just rated at maximum 30 Watts input....
questions over questions..
Quote from: hartiberlin on June 04, 2006, 02:12:49 PM
Fans are very easy to turn,
you don?t need 20 Watts for this, you only have the low wind friction !
Until no prony brake measurements are made, these
above calculations are just speculations,
for instance if the normal 30 Watts fan motor
would only have a 20 to 30 % efficiency the
calculation would be quite different, also it is a question,
if the 30 Watt fan motor would also run at 30 Watts
input all the time or if the input is lower, but the motor
is just rated at maximum 30 Watts input....
questions over questions..
NO THEY ARE NOT.. The fan motor calcs are NOT speculation. IT'S HARD MATH. Just because a blade is easy to spin doesn't mean the motor is not capable of more work than that. Torque curves are based on RPM, PERIOD. More RPM less torque, and vice versa.. Efficiency losses are based on LOAD. Both motors calcs were figured with NO LOAD. And I even allowed for losses, and load in the effective output.
Yes, but you don?t know, at what RPM the Kundel motor really is rotating
and what the windfriction loss power is at that RPM, probably less than 2 Watts...
Quote from: hartiberlin on June 04, 2006, 04:15:05 PM
Yes, but you don?t know, at what RPM the Kundel motor really is rotating
and what the windfriction loss power is at that RPM, probably less than 2 Watts...
I got the figures for RPM from his forums, and yes, you are correct, I don't know what the wind friction, and rpm figures are under load, so that's why I did my calculations based on no load. Remember his motor consumes less power under load, due to the half duty cycle, and lower rpms, and hence slower switching speed/power consumption. This improves efficiency under load, as compared to a fan motor, rather than decrease it.
Again, lack of data forced me to do calculations with no load, and use known values of existing conversion methods estimate the effective output. I was very conservative in my calculations, and never gave his motor the benefit of any doubt. My effective output took 40-60% losses into consideration. Even if I halved that conversion efficiency and took values of 70-80% losses, it would still be 200-375% effective efficiency. Let's be extremely conservative, and say the conversion to electricity is only 10-15% efficient. The output would be 100 to 188% effective efficiency. That's after 85-90% losses during conversion.
The only thing that would make the calculations before conversion to electricity invalid would be his estimated torque.
Understand I'm approaching this very skeptically, but the math doesn't lie.
The only way to know for sure would be to build it, and close the loop. I have already said that. These calculations were simply to get an idea of whether or not it would be worth the effort. And the figures were very promising.