I used an eight pole induction motor, the generating speed was 740 rpm. To excite the coils I drilled and glued a rear earth magnet into the rotor. It generated up to 90 amps at 24v.
People are always concerned about the voltage drop across the diode and usually recommend a schottky diode because it's around 0.2 volts. What you also can do is connect two of them in parallel because diodes still have resistance, it will increase the current. I have done this many times and three diodes in parallel is about the limit, as you won't gain anymore current after that.
Dude Robert you are awesome!!! I’ve seen tons of videos about diodes and capacitors and still couldn’t really grasp the how and what and you just thought me more in the first 60 seconds of this video than hours of videos dedicated towards teaching all about just diodes and just capacitors! Thanks
3:45 and other flashes of that circuit, I'd put the diode first and then the cap, much like the subsequent circuit with transformer. You want to block any back-driving to the generator, but *then* filter that generator output (regulator's input) to be smoothed via the cap.
Great video! I really love those classic videos that explain electricity principles as well, they did a fantastic job and they also spend a good bit of time with it too. Re: The basic circuit, for those who plan to use this to generate a specific voltage, the LM2596 DC to DC is a "Buck" style converter, meaning that it will NOT take a 12 volt generator and give you "more" voltage. So, if you want to power something like 20 volts etc, you will want to use a buck-boost type. Also, don't forget to add a fuse / overload protection into your circuit to protect it from thing like overloads and short circuits.
This reminds me of a pet project I was working on: using a cheap brushed motor, and a couple of cheap op-amps and some in between components, I measured the terminals of the motor as it turned, and fed that into a amps-to-volts converter and then into a voltage integrator and bam! I had a veryyy cheap (albeit not incredibly accurate) rotary encoder from a motor (a motory encoder, as I began to call it)
Thank you Robert for taking the time to quick explain. U inspire me :) just a single mom in the middle of nowhere building my Utopia. 😊 I have no help and no mentors and you have been helping me along my projects well. Thank you. ❤ Yodi Leclaire
Looking forward to seeing the Newman episode, his device could be used either way. A similar design can be found inside a blender. Thanks for the upload Rob !
I would recommend that one uses a capacitor rated for 25% more than the voltage you think you need, the cheap ones can vary by 10% and it's good to have a bit of headroom anyway. Higher voltages aren't hard to find and don't affect the price much either. For anyone not familiar with electronics at-all, you don't need to worry about it if the voltage of your capacitor is vastly greater than the voltage you are working with, there is no ill effect; it's just a tollerance rating. So if the only one you can find is for 400v... fine.
Mind you, that voltage overhead factors into the physical size requirements for a given rating. A 4.7uF cap at 400V is probably electrolytic, while a 400V ceramic capacitor is probably closer to 4.7 nF. 4.7uF ceramics are everywhere, but rated closer to 10V.
@@jercos Actually, you make a good point... you can't just use "any" capacitor... electrolytic caps are polarity sensitive and should not be wired backwards or into ac circuits or they will self-destruct (AFAIK).
Wow i am very glad i stumbled across this video. I've always been fascinated in wonder how to convert electricity I've never really understood stepson was confident enough to experiment with it because I didn't have an idea of what components I would need where to start with it but I thank you for the video very well explain even for me being a newbie at all this I shall continue to follow along and see what else I can learn thanks Robert 🎉cheers🎉
Just an observation, I believe that you want that diode between the motor and capacitor to stop a back feed. You have it after the capacitor so it would in fact back feed when the motor/generator is stopped.
Excellent basic explanation, I think all outputs are DC with the diode and buck module. I think you said AC, but I could be wrong. However, an excellent basic description of different types of motors that are used as generators.
Thank you Robert. Always learn something in each of your videos. One little comment I have is could you maybe have your mic just a little closer. Have my volume turned all the way up on my computer and still hard to hear with my old tired ears. Thanks and have a great day.
I realized a couple days ago that while I will never be able to afford even a self build of a home battery, I might be able to afford a small one plus a good sized pile of supercaps. Since it's almost always windy where I'm at it will only be a few hours at night, if anything, where windspeed would be dead calm. If I can keep the house awake for those periods, which are usually low demand anyhow, then it would be rare for me to need to draw from mains. When they call about how I'm not using any power, I will offer to sell them my surplus back if they like. In this way I put the ball in their court because currently you have to request to have the two way meter installed and also pay for it yourself - if they are calling me then I can offer them my power instead of asking for the meter and there's a chance they'll just agree to install it, especially when I tell them I'd rather just give it to my neighbors for free rather than pay for a meter which will take decades (it's expensive, you have to rebuild your whole mains connection to the grid) to return its value, if it lasts long enough to do so. How to give it away? Put up a charging port at my mailbox that has a light on when there is spare power; give my neighbors a key code to operate it.
As a rule I select a capacitor voltage rating twice the expected value of the input voltage. Voltages are stated as RMS value but the voltage coming in is Peak to peak. Peak to peak voltage = (say) 240 x 1.414
not sure if this would make any improvement. I was thinking with serpentine coil, that you might put metal screws between the loops. Like on the Mighty Mite only difference the coil goes all around.
The brushes in an alternator provides the voltage to produce the magnetic field in the rotor which is used to induce a current in the stator windings. This is because car alternators generally don't have permanent magnets. A regulated DC voltage is applied through the brushes to produce the magnetic field at a magnitude that will induce the desired current and voltage output in the stator windings. This is then rectified by the three-phase bridge rectifier and smoothed by a capacitor. The shape of the rotor bends the magnetic field generated through the rotor coil into two sets of pole pairs that alternate around the circumference of the rotor. The voltage regulator works by sampling the three-phase output of the stator through a set of diodes usually termed the diode trio, which is not to be confused with the rectifier bridge. The voltage regulator then takes this information and determines the best input voltage to be applied to the brushes that will keep the output voltage within range. These days the voltage regulator of many cars has a logic circuit that communicates with the ECM to further control the output of the alternator based on more factors than simply the desired voltage and current.
I have loads of small 12v dc motors from fans from busses and whatnot. I’d like to build small vertical blades for little wind harvesters and series them up to charge a 48v battery bank. Would I rectify and smooth and regulate before or after series connections?
Wouldn't you want the diode before the capacitor so that once you have energy into the capacitor it does not try to flow back into the motor and turn the motor?
So I got as far a making model windcatcher with a 2" ish outlet and then started to look at a turbine blade. It almost seems like performance wise its so small only brushed motor would work so i would not have to move the magnets with what you might get from it. I might just log rpm instead tbh. Although arguably i did actually want it to work. 😄 Just for fun how would you then deal with that 50v you keep getting though the 40v voltage transformer?
Hi Robert I love your show. Maybe you've done it before but, I have 2 x cordless drills brushless 12v that's going to make good wind generators. Any ideas on that?
Here is a clarification I'd like to obtain. Which type of motor makes the most efficient generator, measured by (power in) divided by (power out). Pi/Po x 100% = % efficiency. This measure is important for hand or foot powered generators. Thank you for any feedback.
There are so many different types of generators and cost becomes a factor too. Generally speaking tho the formula for efficiency of a motor is based on the (HP output * 746)/ watts input. Multiply the whole thing * 100 for the percent efficiency. So, if you see a motor rated at 3/4 hp, and it takes 1000 watts to power it: (0.75 * 746) / 746 = .75, then multiply * 100 => 75% efficiency. Since you can usually convert motors into a something that generates electricity, my guess would be that the you would have more losses since you have to find a way to turn the motor shaft and usually that is rather inefficient. Turning the motor shaft manually creates electricity, tho as some commenters have already mentioned, it depends on the motor... for permanent magnet motors is is easy, but for some motors if they don't have a residual magnetic field or a way to create a magnetic field, it will be a problem.
@@marcfruchtman9473 I just talked to my son about this and he said that one can obtain electric motors for model aircraft use which have an efficiency of over 90%. I'm going to look into those. They are 3 phase motors, and with Schottky diodes to rectify the output Voltage, may make quite a decent hand powered generator.
@@BasementEngineer Sounds good. Let me know how it goes! I am curious about the internals of those motors... Do they have some sort of permanent magnet?
@@marcfruchtman9473 These model airplane motors are called outrunners. What is normally the rotating armature with windings, is stationary in these motors and the permanent magnet field rotating as a shell around the stationary windings. Thus no brushes are necessary. These motors are very compact and powerful for their size
How do you put a tiny generator to use when electricity is cheap at large scale? I could see powering a weather station with wind, or lighting somewhere away from utilities on light hydro-power, but having them spinning anywhere there's mains available and little free mechanical energy to collect is a bit silly.
Unfortunately using headphones didn't help me on this one. And I can read lips also. I thought I might be the only one having trouble hearing him tonight. 😪 That being said, i love this series/channel . Just please be more careful with audio levels in future videos. Please?
If you're loading the alternator heavily... at 50% efficiency, a 100-amp 12-volt alternator is going to need about 4 horsepower at full load. You might spin it up just connected to the capacitor, then let momentum handle the inrush current when you connect it to a load. An unloaded alternator should spin by hand if it's not damaged.
Rob I think you may want to move the capacitor to the other side of the diode in your diagram because it might mislead some people who try to make a portable generator to use for charging their phone or a nother small device. The capacitor would try to turn the generator back into a motor IF it's a DC motor.
Several minutes of this one I cannot understand at all what he is saying. Between the speed of speech, accent, and varying levels of engagement with the microphone.
Наука
Impressive explanation! That's what many engineering professors can't do, yet you did it in simpler concept and strategy.
I used an eight pole induction motor, the generating speed was 740 rpm. To excite the coils I drilled and glued a rear earth magnet into the rotor. It generated up to 90 amps at 24v.
You should put up a video on this, and please share the link.
People are always concerned about the voltage drop across the diode and usually recommend a schottky diode because it's around 0.2 volts. What you also can do is connect two of them in parallel because diodes still have resistance, it will increase the current.
I have done this many times and three diodes in parallel is about the limit, as you won't gain anymore current after that.
Thank you Robert, as always, inspiring and informative!!
(With the added Evil Genius Laugh!!) Brilliant!!❤
Dude Robert you are awesome!!! I’ve seen tons of videos about diodes and capacitors and still couldn’t really grasp the how and what and you just thought me more in the first 60 seconds of this video than hours of videos dedicated towards teaching all about just diodes and just capacitors! Thanks
3:45 and other flashes of that circuit, I'd put the diode first and then the cap, much like the subsequent circuit with transformer.
You want to block any back-driving to the generator, but *then* filter that generator output (regulator's input) to be smoothed via the cap.
Invaluable information for us novices. My compliments !
Great video! I really love those classic videos that explain electricity principles as well, they did a fantastic job and they also spend a good bit of time with it too.
Re: The basic circuit, for those who plan to use this to generate a specific voltage, the LM2596 DC to DC is a "Buck" style converter, meaning that it will NOT take a 12 volt generator and give you "more" voltage. So, if you want to power something like 20 volts etc, you will want to use a buck-boost type.
Also, don't forget to add a fuse / overload protection into your circuit to protect it from thing like overloads and short circuits.
This reminds me of a pet project I was working on: using a cheap brushed motor, and a couple of cheap op-amps and some in between components, I measured the terminals of the motor as it turned, and fed that into a amps-to-volts converter and then into a voltage integrator and bam! I had a veryyy cheap (albeit not incredibly accurate) rotary encoder from a motor (a motory encoder, as I began to call it)
Thank you Robert for taking the time to quick explain. U inspire me :) just a single mom in the middle of nowhere building my Utopia. 😊 I have no help and no mentors and you have been helping me along my projects well. Thank you. ❤ Yodi Leclaire
Looking forward to seeing the Newman episode, his device could be used either way. A similar design can be found inside a blender.
Thanks for the upload Rob !
I would recommend that one uses a capacitor rated for 25% more than the voltage you think you need, the cheap ones can vary by 10% and it's good to have a bit of headroom anyway.
Higher voltages aren't hard to find and don't affect the price much either.
For anyone not familiar with electronics at-all, you don't need to worry about it if the voltage of your capacitor is vastly greater than the voltage you are working with, there is no ill effect; it's just a tollerance rating. So if the only one you can find is for 400v... fine.
Mind you, that voltage overhead factors into the physical size requirements for a given rating. A 4.7uF cap at 400V is probably electrolytic, while a 400V ceramic capacitor is probably closer to 4.7 nF. 4.7uF ceramics are everywhere, but rated closer to 10V.
@@jercos Actually, you make a good point... you can't just use "any" capacitor... electrolytic caps are polarity sensitive and should not be wired backwards or into ac circuits or they will self-destruct (AFAIK).
Wow i am very glad i stumbled across this video. I've always been fascinated in wonder how to convert electricity I've never really understood stepson was confident enough to experiment with it because I didn't have an idea of what components I would need where to start with it but I thank you for the video very well explain even for me being a newbie at all this I shall continue to follow along and see what else I can learn thanks Robert 🎉cheers🎉
A video on generators without permanent magnets (besides in the exciter maybe) like you see in powerplants would be cool.
Awesome information on this! Thank you sir!!!
Agreed with most comments here🎉 faboulous explanation that makes ideas click🎉
Funny, I just built your axial flux generator and am adding the capacitors as I watch this!
Just an observation, I believe that you want that diode between the motor and capacitor to stop a back feed. You have it after the capacitor so it would in fact back feed when the motor/generator is stopped.
Well spotted
Excellent basic explanation, I think all outputs are DC with the diode and buck module. I think you said AC, but I could be wrong. However, an excellent basic description of different types of motors that are used as generators.
I realized my bike has steel spokes. I'm considering setting up a reluctance genartor with the spokes passing by the magnet
Thank you Robert. Always learn something in each of your videos. One little comment I have is could you maybe have your mic just a little closer. Have my volume turned all the way up on my computer and still hard to hear with my old tired ears. Thanks and have a great day.
A little Bluetooth lapel microphone would be great, especially when RMS is “out in the field” 👍
The best performance one can obtain is to match the impedance and the capacitance.
It is worth keeping the AC for more efficient transmission and convert to DC only at the battery site.
My head's spinning!
I find that the easiest regulator to use is a solar charge controller. For a 12 volt battery you can input up to 50 volts into the charge controller
Even basic cheap pwm charge controllers should do this.
I realized a couple days ago that while I will never be able to afford even a self build of a home battery, I might be able to afford a small one plus a good sized pile of supercaps. Since it's almost always windy where I'm at it will only be a few hours at night, if anything, where windspeed would be dead calm. If I can keep the house awake for those periods, which are usually low demand anyhow, then it would be rare for me to need to draw from mains. When they call about how I'm not using any power, I will offer to sell them my surplus back if they like. In this way I put the ball in their court because currently you have to request to have the two way meter installed and also pay for it yourself - if they are calling me then I can offer them my power instead of asking for the meter and there's a chance they'll just agree to install it, especially when I tell them I'd rather just give it to my neighbors for free rather than pay for a meter which will take decades (it's expensive, you have to rebuild your whole mains connection to the grid) to return its value, if it lasts long enough to do so.
How to give it away? Put up a charging port at my mailbox that has a light on when there is spare power; give my neighbors a key code to operate it.
Good tech explanation 👏 👍
wish i had my headphones on for this one but i can read lips
As a rule I select a capacitor voltage rating twice the expected value of the input voltage. Voltages are stated as RMS value but the voltage coming in is Peak to peak. Peak to peak voltage = (say) 240 x 1.414
Yes, that is an excellent point.
I wonder if you can use a transistor oscillator to make pulsed dc to run a motor.
Just noticed you have the cap first. Electrolytic capacitors will fail if AC is applied. And could explode.
not sure if this would make any improvement. I was thinking with serpentine coil, that you might put metal screws between the loops. Like on the Mighty Mite only difference the coil goes all around.
Good old diodes....think of them as a one way valve.... --->I
Great video, on another point what do you think of the domestic wind turbine design on you tube, the Liam F1?
I'd love to see what you'd do with a tesla turbine. From my understanding it has immense potential for producing and harvesting energy
The brushes in an alternator provides the voltage to produce the magnetic field in the rotor which is used to induce a current in the stator windings. This is because car alternators generally don't have permanent magnets. A regulated DC voltage is applied through the brushes to produce the magnetic field at a magnitude that will induce the desired current and voltage output in the stator windings. This is then rectified by the three-phase bridge rectifier and smoothed by a capacitor.
The shape of the rotor bends the magnetic field generated through the rotor coil into two sets of pole pairs that alternate around the circumference of the rotor.
The voltage regulator works by sampling the three-phase output of the stator through a set of diodes usually termed the diode trio, which is not to be confused with the rectifier bridge. The voltage regulator then takes this information and determines the best input voltage to be applied to the brushes that will keep the output voltage within range. These days the voltage regulator of many cars has a logic circuit that communicates with the ECM to further control the output of the alternator based on more factors than simply the desired voltage and current.
I have loads of small 12v dc motors from fans from busses and whatnot.
I’d like to build small vertical blades for little wind harvesters and series them up to charge a 48v battery bank.
Would I rectify and smooth and regulate before or after series connections?
Wouldn't you want the diode before the capacitor so that once you have energy into the capacitor it does not try to flow back into the motor and turn the motor?
So I got as far a making model windcatcher with a 2" ish outlet and then started to look at a turbine blade. It almost seems like performance wise its so small only brushed motor would work so i would not have to move the magnets with what you might get from it. I might just log rpm instead tbh. Although arguably i did actually want it to work. 😄
Just for fun how would you then deal with that 50v you keep getting though the 40v voltage transformer?
Are you suggesting that the Daleks were mugs?
Hi Robert
I love your show.
Maybe you've done it before but, I have 2 x cordless drills brushless 12v that's going to make good wind generators. Any ideas on that?
Is that diode anode and cathode in rigt place..In brdge cathode is Vo and anode is groud, or minus..
I was eating potato chips as I watched this" I feel like I missed something ;))
My feeling exactly… 😢
Here is a clarification I'd like to obtain. Which type of motor makes the most efficient generator, measured by (power in) divided by (power out). Pi/Po x 100% = % efficiency.
This measure is important for hand or foot powered generators.
Thank you for any feedback.
There are so many different types of generators and cost becomes a factor too. Generally speaking tho the formula for efficiency of a motor is based on the (HP output * 746)/ watts input. Multiply the whole thing * 100 for the percent efficiency.
So, if you see a motor rated at 3/4 hp, and it takes 1000 watts to power it: (0.75 * 746) / 746 = .75, then multiply * 100 => 75% efficiency.
Since you can usually convert motors into a something that generates electricity, my guess would be that the you would have more losses since you have to find a way to turn the motor shaft and usually that is rather inefficient. Turning the motor shaft manually creates electricity, tho as some commenters have already mentioned, it depends on the motor... for permanent magnet motors is is easy, but for some motors if they don't have a residual magnetic field or a way to create a magnetic field, it will be a problem.
@@marcfruchtman9473 I just talked to my son about this and he said that one can obtain electric motors for model aircraft use which have an efficiency of over 90%.
I'm going to look into those.
They are 3 phase motors, and with Schottky diodes to rectify the output Voltage, may make quite a decent hand powered generator.
@@BasementEngineer Sounds good. Let me know how it goes! I am curious about the internals of those motors... Do they have some sort of permanent magnet?
@@marcfruchtman9473 These model airplane motors are called outrunners.
What is normally the rotating armature with windings, is stationary in these motors and the permanent magnet field rotating as a shell around the stationary windings.
Thus no brushes are necessary.
These motors are very compact and powerful for their size
I'm just curious....do you have any of the devices you've made generating power for you? Would be a shame not to put these to practical use
How do you put a tiny generator to use when electricity is cheap at large scale? I could see powering a weather station with wind, or lighting somewhere away from utilities on light hydro-power, but having them spinning anywhere there's mains available and little free mechanical energy to collect is a bit silly.
@@jercosNo it is not silly. And in case you didn’t know electricity is no longer cheap and it is getting more and more expensive.
How about using alternators as generators?
Unfortunately using headphones didn't help me on this one. And I can read lips also. I thought I might be the only one having trouble hearing him tonight. 😪 That being said, i love this series/channel . Just please be more careful with audio levels in future videos. Please?
I tried that alternator plan, but it failed dismally. The alternator require an enormous amount of torque to turn. It was was an amazing failure...
You were using the wind? Or water to power it? I'm currently assembling a rig to use the creek in my backyard... I hope it's enough torque. 🙏
@@mrimc 1.5meter wind turbine
If you're loading the alternator heavily... at 50% efficiency, a 100-amp 12-volt alternator is going to need about 4 horsepower at full load. You might spin it up just connected to the capacitor, then let momentum handle the inrush current when you connect it to a load. An unloaded alternator should spin by hand if it's not damaged.
Avoiding magnets? Possible? .. if you research how they make magnets & where it comes from .. you will see the point ..
Rob I think you may want to move the capacitor to the other side of the diode in your diagram because it might mislead some people who try to make a portable generator to use for charging their phone or a nother small device. The capacitor would try to turn the generator back into a motor IF it's a DC motor.
can't hear! try again
Several minutes of this one I cannot understand at all what he is saying. Between the speed of speech, accent, and varying levels of engagement with the microphone.