Many years ago I found that putting a few small magnets in the gaps of the rotor would be able to produce enough voltage to feed the commutator at a low speed of 800 rpm. With a simple regulator circuit I designed it allowed me to run a wind mill without the use of a battery to feed the rotor electromagnet. It had an interesting side effect that at low wind speed the windmill ran at high speed with little loading and still generated more voltage on the commutator as the rotor was not acting like a break due to a high current from a battery. The concept was simple, the small magnets allow the commutator to produce a 14 volts with little loading of the windmill blades by the rotor as the magnets are small. Once the voltage gets to 14 volts the circuit allows some of the current / voltage produced back into the rotor via the commutator. If the windmill speed drops due to the extra loading by the rotor electromagnet the output voltage also drops and so via the reg circuit the the current to the rotor also drops. End result is an auto regulating windmill designed to get optimum power from any wind speed.
Harry Bartelink I think as you said above, that maybe the back emf got diverted to powering the electromagnet coil or routed to useable current ( work). If you can make a video of your build or your simple relay, showing things it would be very helpful to see. I am not advanced enough in motors and electronics to figure it out by myself. Thanks for the post.
@@reypolice5231 . I am a busy guy despite being so called retired. I will see if I have a spare hour or 2 in her next few weeks to put a video together to help you understand better.
Something I have noticed when dealing with the old DC automotive generators, is that you can usually feed the output back into the field coils. There seems to be enough residual magnetism in the armature to produce a small current which will create a positive feedback loop-no external power source needed. If you used this setup on a wind turbine I would expect the startup torque to be very low, since there would be virtually no magnetic field at 0 rpm.
They were designed this way so in the car, if the battery is completely dead or disconnected and you bump start the car the ignition would still work. As the electrical load on modern cars is significantly higher Computers + ABS + EPS this is less feasible, but the principle can still be used. You could probably attach a reasonable capacitor in the output and then have the system operate as a brake even if the output cables become disconnected, reducing the risk of the turbine from becoming damaged in high winds.
@@andrewharpin6749 : You want to apply a smidge of care when attaching capacitors, as it can cause oscillation- if you don't factor that into the design, then you may produce an AC generator when you intended a DC one.
The really exciting bit is being able to capture the lost energy when wind speed is too high or low. Removing the need for braking systems should reduce cost and maintenance, I would assume.
Brilliant video. Thank you. There is a video on Victron Energy's channel on charging lithium batteries from an alternator. Could be worth a look and perhaps to do an experiment on. Alternarors are super readily available and as you always say, the less done, the better the efficiency
@@ThinkingandTinkering Could you make a hybrid self-balancing system. A longer shaft with a secondary permanent magnet generator on the back that additionally feeds the coil on the other side, automatically adjusting the torque and main power output of the primary generator?
Saw a system like this employed by a bar owner on a mile wide gravel wash created by a volcanic eruption in St Vincent. It was a no-mans land frequented by gravel seeking trucks and travelers passing thru. The device was powered by a bank of vehicle radiator fans all connected by old belts to charge a scavenged battery bank. He ran a stereo, sold drinks and small foods, and gave away kittens...
Was working on this before my move 3 years ago too the mountains, was going too continue when I finished my new home/cabin, then a wildfire burned all my equipment/ electronics/ components and all my trees and cabin, shop, outhouse, Everything. Don't know if I'll ever finish, I'm 66, but have begun again. Cheers!
I have an old alternator with stuffed brushes and have always thought there had to be ways to make it brushless. I have a wide array of magnets also including a big ring speaker magnet like you had. I guess it's one of those tuit jobs, if I ever get around. 😂
He brings up an important point with the placement of the magnets, and he's right, but it does have problems. Using a speaker magnet may not provide enough magnetic force to induce much of a current. The greater the amount of iron/steel, the stronger magnet you'll need to saturate the core. The further the source magnetism is from the coil in which the current is being induced, the weaker the field will be. That's why they drill holes in the metal to place the magnets directly near the windings. I was going to do a quick video to show you, but it was quicker to type it instead.
It´s a very interesting video Mr. Murray !!! I´m working in producing some electricity at home with the help of a bike and an alternator. So I had to learn how an alternator works and why a car battery was needed. Then I found that there are at least 3 wastes of energy using this method: 1) The rectification, 2) The charging of the battery and 3) The harvest of the energy from the battery and transformation into AC. And it´s totally ilogical beacuse the alternator produces AC from the beginning (there is where its name comes from). So I decided to eliminate the rectificator and then make 3 AC circuits ( one of which is used to keep the battery charged ). So I have 3 available AC circuits because even the one used to keep the battery charged has sometimes an extra amount of energy that can be used for other minor purposes. But for me the most important is that I don´t lose valuable energy doing senseless transformations of AC to DC and then from DC to AC !!!
Well Robert, guess Google has been listening or reading my RU-vid posts. Just watched a different video and posted your suggestion of my own accord YESTERDAY. I THINK what your saying about energizing the rotor field with say a; high joule Cap, it will initialize a start of magnitizum and with some circuitry on the Regulator, it can control that voltage/amps. It'll take some work,, but I bet you'll get it.
Amazing could you make schematic plan of the 3 mode for making use of an car alternator please. Because I watch over and over , very difficult to try to make , thanks
I'm pretty sure the alternator can do more than 3000rpm, most petrol engines will do over 5000rpm and the pulley on the alternator is smaller than the crankshaft pulley that drives it so it would spin a lot faster than that.
3,000 is where car alternators (in cars) start generating, they need a few more RPMs to get to full output. Pulleys are around 3:1 ratio & tickover is around 1,000 RPM but the 'red line' on smaller engines can be 10,000 RPM so the alternator has to be able to cope with 30,000 RPM. Another issue is that the cooling fan won't be doing much at idling speeds.
I still believe that with no magnet would work better, then you could with an arduino regulate the current of the rotor, having an encoder as a feedback to measure the wind, if, less wind, less current to the rotor less lens law torque,else, more wind, more current to rotor more lens law torque.
Car alternators generally only self-excite under a load. I have an excercise bike electricity generator that I made with a car alternator, and a ~12v battery pack is needed momentarily to start it generating. In a car, this is done by turning on the key. Of course, once it is generating a small amount, then the current sent to the crab-claw coil is sufficient to keep it self-excited.
@@ThinkingandTinkering I'm absolutely hooked, it's all so fascinating.. I've just found myself an ebike motor, looking at a gravity battery, hopefully with a pedal adaptation for travel 👍 your channel has helped me no end so far.. it's truly brilliant, thank you.
can someone point me to a good source to ask noob questions (forum / chat server?) about hooking this kind of generator up to an off grid system? things like sizing of rectifiers, power dump systems etc? somewhere friendly where a noob isn't gonna get electronic snobs taking all the fun out of it?
Thank you. An interesting insight into bending the field(s) fascinating. The speed of rotation that you touched on, is a little conservative. Consider going up through the gears as you drive, crankshaft speed may easily top 4000 plus, if you measure the diameter of both the crank' and alternator pullys and do the calculation we find that the alternator rotates a good lick faster than crank speed. Also not sure I agree that the rotor is permanently energised , it is after all, regulated through transistor switching to control it's state, and ergo fluctuating open circuit / closed circuit.
That's very interesting. I've always been a bit stumped what exactly is going on in claw-pole alternators. I'm having a bit of trouble getting my head around the different configurations and whats going on with the various currents and fields at different rpms. It'll be interesting to see some practical examples/uses, maybe with circuit diagrams. Thanks for the excellent overview. Much appreciated. Is there not a simple way to avoid the high-torque/stalling problem at low rpm, by adding a zener-diode into the energising circuit? That would mean no current, and therefore no torque/brake, until the rotor passes a minimum rpm. Or am I missing something?
Rob showed on his $100 dollar 1kw wind mill that: a capacitor after the coil/ before the battery; will take the load off the generator. It spun freely and produced electric at low RPM. Hope that helps.
A automotive alternator’s regulator controls the field current (strength) and therefore the output voltage of the alternator. It is true that this device is powered from the car battery as there is a necessity to have a power source capable of supplying the significant field current needed to start an alternator under load, as would be the case for wind turbine. Is the feedback from residual magnetism capable of producing this field power under startup for all loads? Something worthy of a tinkerers efforts to find out. If so then why remove the regulator at all as it is a ready made and reliable solution. If not then there are ways to eliminate the load during startup or to provide a small rechargeable battery or to use the systems battery storage, if there is one. Again, something worthy of a tinkerers efforts. Why eliminate the rectifiers or try to rewind the stator other than just to make more work or fun? An automotive alternator is ready to provide a 12V DC system with about 120W of continuous power or almost 3kW-hr a day, enough to power a full sized refrigerator or freezer given a proper setup and tower. Not all alternators have internal regulators. Choosing one with an external regulator would allow for tinkering with the output voltage sensing to increase/decrease the output voltage of the alternator during use might allow for 24V systems at reduced current. In any case I would think that a unmodified automotive alternator used as a wind powered generator would be perfect for a 120W input, battery backup, inverter output renewable system. An interested tinkerer might explore how to arrange multiple alternators to provide 24V or 48V systems at higher wattages, similar to PV arrays. In fact, a combined PV and wind powered system would complement each other and reduce the cost of the unreliability of each one when used alone.
A great explanation of the problem and possible solutions Rob. I always thought that electromagnetic over permanent magnets was a better idea for wind turbine generators. It gets around the cogging problems, or as you say the torque matching to wind speed problems. It would be a relative simple coding job for an Arduino with a look up table, tachometer input and FET switching output to the field coil.
You can try to extract tacho information out of the stator coils before rectifier bridge with small additional circuit and feed to the microcontroller. No magnets and hall switches needed...You can do it on two phases to get redundancy.
Convert low voltage high amperage to higher voltage lower amperage. More amp turns make more practical usage. Thanks. By the way, your audio is very good, no ambient reverulation.
Rob, have you ever used or seen a self exciting alternator. They're used on earth moving equipment and some farm machinery, and they operate on low rpms (1800rpms).
My first thought is to put a smaller wind generator on top of the main wind generator, the output of the smaller wind generator goes into the field coil of the alternator. That way you don't need any fancy computers to automatically set the load value
Run a separate PM generator from the same turbine, but as stated in the video you don't need it as there is sufficient residual magnetism in the alternator that it produces some field.
@@andrewharpin6749 I ran a generator that used the residual magnetism to start it for quite a few years. That doesn't work as reliably as you might think it does.
My antisipation is winding up too! I have the alternator(s) - I need to charge the battery bank... did I say my antisipation is winding up... and up... and... 👍😁
@@andrewharpin6749 : No, it's mostly the consumers bailing out, not the producers. The average producer barely has any profit (takes them about 30 years to pay off a new plant, at which point the have to refurbish it).
Or if you make a small say dc drill/diy/wind generator that makes the dc for the rotor threw the slips.🎩 it could be limited for high speed breaking. The little one could only make so much.?
Most Alternators have enough residual magnesium to create a start voltage. Simply tying the out put to the output it becomes self starting. A resistor can act as a basic regulator.
@@mjolnirswrath23 : Unless utter endurance matters more to you, in which case you hide a rectifier circuit with the speaker coil, hook it to another coil mounted to the same axel, and use that second coil as half of a transformer so you can use a zero-friction charge source.
If I modify the Car Maschine to a permanent Magnet Generator NY fitting of the Claws and replying Them ja permanent Magnets pointing N S N S and so on, how much much more effektive will it bei?
Makes you wonder why all the homes in England with chimneys on don't have a cheap wind generator on them, even to get power to charge phones and stuff. Also makes you wonder if the "electric revolution" isn't being held back until they have all their tax in place. I want to make my own solar system and see how much fuss is created when I want to sell electric back to my supplier.
Love your vids. You remind me of Emmett Lathrop Brown, Ph.D. or "Doc Brown" in Back to the Future, but - of course - unlike him, your stuff actually works! You really should consider growing an unkempt mane of white hair and take to wearing a lab coat!
@@ThinkingandTinkeringmaybe bunch of your roses on the front of the vehicle too 😁and if there's room a flywheel, a bank of supercaps, a rain water generator.. and Elton Musk's wallet lol..
WRONG! Alternators reach maximum output at 5-6k rpm. That is why they are overdriven, just look at the sizes of the crankshaft pulley compared to the alternator pulley. A lot of times it’s 2.5 -3 to 1 ratio. You can safely spin one up to about 15-18k rpm.
Could you use those parts to develop a method of switching through a flux capacitance system so that the rotor acts as the flux switch? Or maybe use a charge controller to switch between the volts and amps of the flux capacitance?
That’s clever thinking Rob. First time I found out how an alternator worked I thought the same….I then pondered on the fact that someone had worked it out in this first place.
So how strong a magnetic field is generated in that dc stator? just thinking in my head about magnet strengths and how that would change voltage output in a permanent magnet set up as well as input torque requirements for charging or output torque in a motor conversion.
duh, I didn't mean stator, I meant rotor. Now interestingly I had a couple spare reman alternators laying around collecting dust so I took one apart and started experimenting. Straight 12 volt battery power to the rotor does not create a very powerful magnet. Enough to hold some nuts and bolts, but if I pull on them maybe a few pounds of force to pull off (yeah, super scientific I know), and the power on the crab claws is pretty weak at that point. So I am wondering if I am doing something wrong, or if it doesn't really take much in the way of magnetism for these things to work. I'm of thinking about putting a permanent magnet inside the crab claw as you mention in this vid, but I don't want to go crazy and have one that takes excessive power to turn, or too weak and end up with one that won't do anything.
Put a wire from the output of the alternator to the input of the field with a rheostat to vary the voltage input....now, attach a 9v battery to the input with a momentary switch. Using the motive force of your choice, spin up the alternator and hit the momentary switch to "initiate" the field and adjust the rheostat to adjust your desired output. We use this technique to make "expedient" portable dc welders....
I wonder it it would be possible to permanently increase the residual magnetism in the stator cores using an external electro magnet? Sort of like giving the stator a one time charge.
Could we use just one phase to activate the electric magnets and the other two to continue to produce power? That would basically allow it to brake itself as the power increased.
Very good explanation for the use of automobile alternators‼️ I'm always so very proud of your work. What an excellent choice for discussion. Active and retired automotive mechanics should be building generators on the side.
Not specifically on this video. However I would like to say that your enthusiasm and style of delivery remind me of the late Prof. Eric Laithwaite of Imperial College. One of my engineering heroes when I was a humble student in Edinburgh. More power to your elbow sir!
