Gosh! Thanks, Tom. I'm so glad it's useful for you. If you're teaching basic electrical science/tech, you may also find some value in my video on electrical grounding. Cheers!
Great video! Amazing lecturer! When it comes to Electrics, you really need to teach it well, if not, you will be stuck. But this lecturer explains it perfectly by the use of humour and audience participation. You can never understand electrics until you see it in practice! Super Super video! Have you got any more videos that include this Lecturer?
Excellent demo of generator as a motor. This gives me so much better knowledge and understanding about generator rotor resistance when using more power.
I agree, your teaching methods are the right way in my opinion. I would love to just have the opportunity the be in that class. I'm more of a visual learner and electric is invisible so your teaching methods are right by me. Good Luck.
my lecturer didn't explain us that much specific and he only show us some videos about the wire moving part and that's why I youtubed it and saw thus video Thanks for explaining
My AC theory teacher was an engineer from the Bell Labs days-when solid state was new. I wish he'd used this 'applied' approach! This was a great video!
@harrysg84 PART 2...That said, the purpose of this lecture was NOT to discourage creativity and exploration...it was one session of a course titled "Survey of Renewable Energy Technology." Rather, the lecture's focus was to give the students a solid grounding in the "proven" principles on which wind-generators function.
I invite you to post a similar, educational video, actually demonstrating functional examples of your "kind of thinking," and proving it will pull us "past the stone age." I'd love to see it! Really!
Absolutely! This demonstration/lecture was one session in a course titled "Survey of Renewable Energy Technology." It was a precursor to follow-up lectures on wind and hydro-driven generators.
The reason for the resistant force when the circuit is closed is because when passing a magnet through the coils and opposing electromagnetic field is created. I have seen pulse motors displayed on RU-vid that will utilize the back emf and harness it to at the very least extend the power source or nearly replace it.
i passed c++ and physics cuz of the internet . just look for the right videos and u might be the new tesla.. just kiddin,tesla makes videos ,videos dont make teslas :D
The unit I used in the video has a PM field and a wound armature. It's a commutated DC unit. The name plate rates it as a 120VDC, 1/2 HP motor, made by Leeson.
Hi E.D. Of course the back-torque and CEMF are "easily" explained by Lenz's Law; BUT, just saying that to students in a Fundamentals of Electricity course often results in a response of, "Duh-h-h?" For beginners, seeing and feeling -- personally experiencing -- a phenomenon is a much more effective teaching/learning method than just saying, "because of Lenz's Law, thus and such will happen." I can clearly imagine their total confusion if I started spitting out words like "concatenate." HA!
Timothy J. Wilhelm of Kankakee Community College in Kankakee, Illinois. Registered Professional Engineer; IREC/ISPQ-Certified Master Trainer for Solar-Photovoltaics; NABCEP-Certified Solar-PV Installer; BSEd in Physics and Math; AAS degrees in Electronics Technology and Industrail Electrical Technology; EPA Class-A Public Water Supply Operator; 2nd dan Tang Soo Do; intrepid survivor of a brutal, intentional hit-and-run -- Dodge Ram 2500 vs. pedestrian.
now I know i am a science person but i always ignored electricity/magnetism, now i am glad i saw this motion | structure | elements/chemicals | energy/electricity/temperature/gravity | accumulative/detriment
how do you increase or decrease torque on a motor ? also is how fast a motor spins a function of how much voltage is applied ? if not what controls motor speed ? thanks in advance
I´ve a question about generators. Most books just says that increasing the speed of the rotational movement that the generator is receiving, it makes it to produce a bigger output voltage. But they don´t tell us how it´s done. So, my question is why the generator produces a large output voltage when it´s RPM is increased?
Speed of DC motors (and Universal motors) varies with appplied voltage. Speed of AC motors (NOT Universal mtors) varies with the frequency of the applied AC power. The only functional way to have a variable-speed AC motor is to use a variable-frequency motor drive, such as the Allen-Bradley 1305.
anyone have any good sources for me to learn know engines work. I want to build something like this but have no knowledge on how they work other than this video. What would you recommend?
@edviperrrr The voltage you are producing has to do with the rate of change of the spinning magnetic field (Faraday's law). You can increase the voltage either by having a bigger magnet in the shaft (i.e., with a higher excitation current, it usually is an electromagnet) or by making it spin faster. Making it go faster is not a practical method since you must agree with the other generators on the rotating speed. So only the excitation current is really used.
Greetings. The "generator" shown in the video has a permanent magnet field. Your question is related to wound-field machines. There are three (3) basic types of wound-field motors/generators: series-wound, shunt-wound, and compound-wound. In all three types, the field winds are electrically connected to the armature windings; and, the fields are electromagnets rather than permanent magnets. The most common form of wound-field machines used as generators is the shunt-wound, in which the field windings are wired in parallel with the armature windings. Also, importantly, the field windings are physically wound on a steel core. A brand new, never-used, wound-field generator will not have any residual magnetism in the steel core of the field winding. Thus, you cannot just spin the shaft and expect it to operate, as there will be no field magnetism with which to induce current in the revolving armature. In order to make the generator operative, you need to "flash the field." This involves running current through the field windings for a short period of time so as to impose a magnetic field on the field winding's core. The steel in the core has enough retentivity as to maintain a residual magnetic field. Now, when the armature is spun, the small, residual field will induce a small current in the armature. Because the armature is wired to the field windings, some of the new current is forced through the field. In turn, this increases the magnetic-field strength in the field winding, and the process continues to cascade upwards to the full operating conditions of the generator.
does that motor/generator have a permanent magnet armature or a wound copper armature? Also, does it produce AC or DC (I think it's DC since it can power a light bulb without and converting, but I can't be sure)?
Hi +tjwiltube Thanks for the great video. You're a great teacher and the fact you show by practical examples really helps. I want to use a motor as a generator for a bicycle generator project. I'm trying to better understand the theory + calculations. Any help is appreciated. If we want to use the motor as a generator and just spin the motor shaft then how do we calculate how much voltage is generated? If e.g. usually at 5V the motor spins at 3000rpms. Then when used as a generator would spinning the motor at 3000rpm generate 5v? When using a motor as a generator: does the speed of rotation affect the voltage generated? Does the electrical load resistance/impedance affect current output? Is current output related to the input torque required? How do we calculate torque and speed required for a certain load? For different loads with the same rated voltage would you need different a torque to spin the shaft and thus to power the load? With a motor that has certain specs. What if you put too much torque or speed in? How is a motor affected by too much torque or speed when used as a generator? I'm trying to understand what will happen if I spin my motor shaft too quickly or with too much torque with the bicycle generator setup I hope to build. Thanks
how much torque would it take generate 100 amps @ 120 volts a/c ( 12,000 watts ) I'm think about a ''shifting weight" rotating& moving the weight out to the edge/outside of the rotating circle from 2 o'clock - 7o'clock position of the circle using a magnetic/moving slide weight system triggered @ the 7 o'clock position sliding the weight toward the 2o'clock position got part of this idea from "oneal3" and Bob Kostoff on you tube. Working on something that is more self-sufficient
Great video. I am building a DIY wind generator and I have been looking for a mathematical formula for back torque in an alternator (PMA). I even looked in books on the fundamentals of electrical machines and still couldn't find such a formula. I hear that back torque is directly proportional to the amount of current produced, but I would find it easier to believe it was a function of both voltage and current, aka power.
Greetings Mr. Mills. Of course, voltage and current are directly related to one another (along with circuit resistance -- i.e. Ohm's Law). That said, it is current that most relates to back torque. Current is what gives rise to the attendant magnetic field -- the greater the current, the stronger the magnetic field; and, it's the magnetic field strength (via the "motor effect" in a generator) that manifests as back torque. FYI! FOR YOUR DIY WIND GENNY! I strongly encourage you to check out www.otherpower.com . These guys (the "Two Dans") REALLY know their stuff, and their plans and book (Homebrew Wind Power) are based on the genius of small-wind guru, Hugh Piggot, and on their own hard-earned experience building multiple iterations of practical and functional wind generators. Best wishes on your DIY project!
thanks! i have the book at home and just read it :) im trying to understand the system through a differential equation. so i need a mathematical term for back torque. cant find it anywhere online, in fact "back torque" only yields a handful of hits on google. i tried to find the dans' emails on the internet but couldnt find them
in order to construct the differential equation its fairly straightforward you need to sum the torques, the torque of the wind on the blades and back torque of the alternator (and then add some linear terms from friction). i am sure the dans know their stuff but its pure guesswork and trial and error until you model it mathematically through a DE. need a formula for back torque!
since i am doing my own design (only thing i will borrow from the dans is their blade design) and i have a gearbox, i need some more math. DE is the only way to truly understand it.
@tug I think you got him wrong! He is not against people being creative,he is showing people the things which by the laws a Physics will come into play when they are trying to create things.Who would want to spend so much money just to come to the point what this great instructor just proved to be a obstacle for him? Free Energy in NOT IMPOSSIBLE,but Yes the way some of these Companies are showing Or some on the people on you tube demonstrate,It is impossible ,& as he said Damn right Dangerous !
SERIOUSLY? Whether it's a cell-phone vibrator, or a vibrating Dildo, these devices all contain a spinning, electric motor. On the end of the motor's shaft is an off-balance weight. When the motor spins, the unbalanced, weighted shaft shakes the entire machanism at a rate then matches the rotational speed of the motor. This is very similar to an automobile wheel that has thrown one of its balancing weights, thus putting the rim into an unbalanced state and causing the entire car to vibrate.
I have a question about back torque. Does it also apply to wind generator and batteries? I mean when load is added to the inverter does the wind generator gets the back torque as well?
@@tjwiltube yes sir, I didn't know which you will see first so I've asked the same question in both quota and RU-vid. Do you mind giving the link about wind generator please? Thank you
I'm sorry, I no longer have the video of the full lecture. That said, this is the essence of the whole thing. I just removed all the side talk and repetition of the same demonstrations.
If the generator and motor fight against one another why can't you put a blocking diode in to prevent the motor from fighting against the generator? The blocking diode would prevent a reverse flow of the electricity.
Observ45er I should not have said reverse that is not a good way to put it because you are correct it does not try to reverse it's direction. However if it is stopped fast enough the force of it stopping could cause it to move in the opposite direction kind of like when you throw a ball at a wall the momentum is redirected so the ball changes its direction.
Tyson Capel It isn't a good description to say that " the motor [is] fighting against the generator". That isn't decriptive of what is going on. Well, the instructor in that video does say that the effect is like it is trying to turn in reverse; applying Fleming's Right and Left Hand rules appropriately shows this resistance (opposing force) and if you actually do apply an external current in the same direction it verifies that the generator does turn the other way, so it is sort-of not as wrong to say it, in a simple analogy sense only. ... It is just that I think it is better to point out that the resistance you feel in turning the generator is the energy needed to do whatever work the electricity is doing, like lighting the light. It is a good place to introduce that concept and it teaches that there is a conversion of energy going on (mechanical to electrical to ...) and that there is no free energy nor over unity possible. It reenforces the concept that energy is neither created nor destroyed; it is only changed into another form. ... Googling "Back Torque" ( a term I hadn't heard before) I see many references to people trying to elimanate it in a generator, apparently in a desire to get electrical energy out of a generator withoug putting any mechanical energy into it. Too many people still think scientists have not discovered enough about electromagnetics ... or that scientists are in a secret society collecting money from fooling others so they can make lots of money hiding the secrets of science and make fools out of all 'them' peons. Gotta run to pick up my check... Cheers, ScienceAdvisorSteve
***** You're welcome. When all this stuff is correctly understood, it is amazing how it all fits together and reveals what has been described as the "beauty of science". I just report what has been carefully studied and is well understood. Many are amazed by the simplest of science and it appears that many do not have a very good idea how much of the fundamental laws/rules of nature are well understood. Many confuse technology with the fundamental science upon which it is built. Many commenters seem to think that all the fundamental laws of nature will be completely overturned by something 'discovered' by a hobbiest in the garage with poor equipment and less understanding of what they are observing. ... As I recall, this is a nice demonstration and a full understanding should be had by watching and listening to the whole course. not just sound bites. ... Good luck in your studies of 'nature'. Cheers.
Hi Matt. I have explored "free energy" for over 40 years. In all that time, I've never found anything that really works...only people who swear it does. The proof is in the pudding, as the old saying goes. If "free energy" is real, perspectives and attitudes will not prevent it from working unless it relies on psychic energy to make a shaft spin. I invite and welcome you (or anyone) to share a video here of a legitimate, functioning "free energy" device.
Solar power is free energy, wind power is free energy, water fall is free energy, once you build a devices the you can harness the energy. But I like the most is magnetic power, it produce 24/7 but you have to built the device to harness the energy . After that is free energy. No fossil fuel needed.
You state building an exercise bike generator would be futile because of the energy it would take to do any good. How about a generator powered by gravity? Imagine 500 pounds hanging from a gear system that would turn a generator... Or how about a couple of tons? Now, one would need to jack the weight up some how after it dropped ... but it may be better than a bike. Thoughts?
you wouldn't be able to generate electricity the whole 360 degrees . might have to make the generator into a motor part of the rotation to maintain a constant rotational speed. this would require only part of the amount of the generated power.
Also, this is the reason why humans can't get past the stone age. This kind of thinking is like the flat earth people, and the, "this is the way we always do it."
@tugasub For the open-minded, "play" reveals an interesting fact, that the entire universe is absolutely controlled by well-defined "natural laws." These laws are inviolable & immutable. Most free energy proponents propose schemes that violate these laws...humbug! A few discovered free energy schemes that are in full accord with natural law. Legitimate free energy folk include T. Henry Moray, William Hooper, and Nicola Tesla. They all appreciated "old school" facts and realities.
@harrysg84 PART 1...Thanks, Harry. I understand where you're coming from, maybe better than you think. I've been an avid "free energy" researcher since the late 1960's. I'm glad you used the word "proven" in your comments; because in 40 years of researching and actually testing so-called "free energy" devices, experience proved that most of them were total humbug and only a few held the potential to be legitimate.
