Use A Small DC Motor As A Generator? (4K)

[@Hepad_]

In a energy loss chain you MULTIPLY the efficiencies, not add them. Assuming the motors have equal efficiencies, you should take the square root of the efficiency of the couple motors, not double it. The efficiency of a motor thus is 39.07 %.

[@sidebo1]

The efficiency of a DC motor depends on the mechanical load (torque) applied. I suspect the observed efficiency here would depend on the electrical load, which is controlled by the value of the resistor placed in. It's possible that higher efficiency would be achieved for different R values chosen. It's kind of an "impedance matching" behavior.

[@Markste-in]

You didn't measure the efficiency of one motor but of the System "Motor-Motor". That means you calculated Peff = Power_in/Power_out = P_M1 * P_M2. Assuming both motors are the same the efficiency of one motor is sqrt(Peff)

[@vicchavez6570]

A small 3 step 12 volt Dc motor lights up a 25 wat bulb just by spinning it with your fingers. Motors from laser printers work the best.

[@Robert_1667]

Can a DC motor work?

[@vicchavez6570]

​@Robert_1667 a 3 phase stepper motor will.

[@Robert_1667]

Ah, alright

[@MamaGypsyFelice]

I 100% appreciate you doing this. Thank you very much.

[@dinosaur0073]

Thank you very much.....I was also planning to do same experiment, but now you saved my time.... The results not good enough to be used as wind turbines....thanks

[@tsbrownie]

I was rather disappointed. I have seen some really expensive DC motors that might work. The one I have (in pieces) came from a battery powered nail gun. Need to find another one like that and re-run the tests.

[@WarThunderRager]

1st video of yours iv ever seen, i its brilliant, thank you, very informative. Thank you.

[@Akrub1979]

That's some weird way to calculate efficiency. On a (generous) assumption that efficiency of the motor running as drive and one running as generator, you should take square root of the 15% - which gives you 39% efficiency of each motor.

[@barzeen3361]

nani?

[@-nivek6489]

@@barzeen3361 i dont know the correct equation but there is an equation that takes the voltage input and voltage output and i think current of both, this equation allows you to measure the efficency of the system. I reiterate i dont know the correct equation, its probably something you can google

[@Akrub1979]

@CSD Studio "efficiency = output / input" - I fully agree. I have nothing against the way he calculated 15% efficiecy. I disagree with the transition to 30,54% efficiency per motor. When you have a number of devices in series, I think, you should multiply efficiencies. Efficency of system = Eff1 * Eff2. The author assumed, both motors have same efficiency - which would mean taking square root to calculate efficiency of a single motor in this case.

[@Akrub1979]

@CSD Studio OK, I think, the main problem is that english is my second language. You say, that "series" is only devices performing same task. (all the motors converting electricy to mechanical work, or the other way round) right? So, to be on the same page: how should I call a set of devices, each converting energy from the previous one? Like in this video, one motor is converting electrical to mechanical energy, the second one - the other way? (or - in a more real life example: generator to compressor to pneumatic screwdriver)

[@personal.YouTube.channel]

I have a question ? That maybe you can help me with. I'm a bushcrafter. I'm looking at making a somewhat Lightweight. ( The lighter the better ) Backpackable hydro generator. Power wise I'm looking at trying to have something that will 5 volt & as close as I can get 2 amps. The plan is to put a relatively efficient propeller onto the motor shaft in a waterproof container. Allowing the faster moving water to spin the propeller. To generate some electricity. With a power wire coming off of it. Attached to the 550 cord. To support the water turbine & give the power cord a safe place to rest. With the hope of having 2 USB plugs at the end of the cord. To powered my devices What type of generator/ motor would you recommend for this? Trying to keep it light & as small as possible for backpacking.

[@tsbrownie]

To be upfront, I've never done that, but I have seen somethings on the internet. I can't remember specifics, but I found some googling "portable hydrogenerator". The best motors I have found that work as generators (and happen to be water resistant) are from RO water filters. When the pumps go bad, the motors still have a lot of life in them. They should be able to produce the voltage and amperage you want. If you have access to a 3D printer, you can probably print a head to fit those motors. Also, I just looked on "thingiverse.com" using "hydro generator" and found some there. They look low amp, but might be scalable to an RO water filter motor.

[@XXXXXLSBXXXXX]

Thank you very much sir! I am an undergraduate senior faced with taking on my capstone project during COVID. We have no access to the lab for safety reasons so it has been very difficult to find data related to my project. I needed to perform an experiment to determine the efficiency of small dc motors being used as generators and THIS VIDEO WAS PERFECT! I appreciate your effort very much. Do I have permission to cite this data in my proposal?

[@tsbrownie]

I'm glad to have helped. Yes, you can cite the video as a reference, I don't plan to take it down for a long time.

[@jeffreylielferrer3862]

@@tsbrownie sir hello to you, i have a few questions I would like to ask for a project, is it okay to ask for your email and ask you for a few questions privately?

[@tsbrownie]

@@jeffreylielferrer3862 Please leave your questions here in the comments. Look forward to it.

[@jeffreylielferrer3862]

@@tsbrownie uhhmm actually sir my questions might take a long discussion sir😅😅,would that be okay to do it here sir?

[@tsbrownie]

@@jeffreylielferrer3862 Here is good. Let others share our brilliance! ;)

[@lvl76hobo11]

You Sir, are a genius. This is like some advanced mystical alchemy to me. Wow

[@humphrey2108]

If the volmeter is set to dc it will only measure the DC avergage. All ripple (AC) will not be be measured but is transferred energy.

[@MrStevenDeer]

Question, would adding a gearbox to the generator motor increase its efficiency?

[@tsbrownie]

In theory it might, but if you spin these motors too fast the brushes will not stay in contact with the armature, then there is the additional friction of the gears.

[@limehuzki]

@@tsbrownie what if you put a lower energy consuming motor , connected to a friction reduction gearbox, attached to a higher end generator..... Probably wouldn't work but it would be fun to see SOMEONE on the internet try it^^

[@whatthefuckallhandlesaretaken]

@@tsbrownie Can you repeat the experiment with brushless motors and brushless dynamo generator?

[@tsbrownie]

@@whatthefuckallhandlesaretaken From my experience it will actually do worse. A good, low friction brushed motor will transfer more electricity than an induction motor, but I will put it on my list. It's going to take a while to find the motors.

[@MaaZy_]

What a great video and experiment 👏👍 .. thank you

[@williamsawyer9768]

I was hoping you had a simple gear set. To over speed the generator side. Idk how much of a gain that would be. I'm sure it differs between gear ratios. Would it even be worth it to bother. Theres a idea for a video.

[@whatelseison8970]

It would make more sense to compute the mechanical power input to your generator based on torque*speed, not simply assuming that the motor should have similar losses whether used as a motor or generator. I don't think that's a safe assumption at all.

[@roycas3]

You need to match the speed to torque curve and decide the load resister value for the best efficiency.

[@paulgreyvensteyn7399]

Question, I have a 12V 30W 3000rpm DC motor, if use it as a generator and for example rotate it at 1500rpm what will the power generated be? Is it depended on the “load” connected to the circuit? And how do I measure the maximum output then? Thank you.

[@tsbrownie]

It really depends on the construction of the motor. You can only guess based on some % of its wattage. Maybe 10 to 20 watts. The most accurate way to measure is in use.

[@TrevorGray4758]

If you put it on a belt system you can match output with input or increase your generator with gear reduction.

[@tsbrownie]

True you can change the ratio, but friction belts take a minimum of about 20% of the power of the system. Can't remember what toothed belts take, but it's not zero. So then you have to make more power to make up for belt losses. It's a spiral.

[@dinukasheheranbowattha5907]

Your the best teacher....

[@randmcnally6442]

What can I use for a generator, using water current to turn the motor?

[@tsbrownie]

Depends on size, but I have a video on the DC motors from an RO water filter and they seem to work well and be higher quality. kzbin.info/www/bejne/pYPdYaxqjJ6ig5I

[@JDhvactech]

there is no drag on those motors try it with a drill motor with the gears still on way diffrent results

[@corireff4361]

So if you gear them correctly theoretically you could get more output

[@shllshl1453]

They go in gear boxes for the toddler hot wheels type cars you can use the output of the gear box to turn a car alternator.

[@johnfarthing4713]

Interesting topic since I have been trying to connect 10 with fans on them as 1 windturbine. My friend who is a master electrician said I need to match all motors to eliminate impedance

[@tsbrownie]

There's a few things that can reduce efficiency with a multi-generator setup. It depends on how you connect them. Especially if you choose serial (lots of issues) verses parallel. I think the biggest issue would be the tendency for some motors to act as generators, and others to consume power as motors. That can be fixed by putting diodes (or controllers) on each motor (this assumes DC generators).

[@johnfarthing4713]

@@tsbrownie thanks for response. At one time I took 2 for a ride in car and got 12v , guess I should just keep and until I find 1 that doesn't work and try another until I get a string of them.

[@fahrurofiq6457]

it is interesting practise by modifying the magnite of generator to neodymium then put V-i correlation as a chart. it's usually more easily to understand how performance is

[@hondacivc93]

Load up the generator side with a field current. How efficient COULD that setup produce. I want to see some smoke

[@knowledgehub872]

Hi sir... What if we use a higher rating motor as a driving motor. I think efficiency would increase.

[@ScreenPrintR]

What about adding a fan and let that generate electricity?

[@tsbrownie]

Yes, blades can be used to turn it.

[@sierraecho884]

I would like to build a small stirling generator to produce ca. 2W-15W output with a small USB 5V plug to charge a phone and such, just for fun. Which motor would you guys recommend ? I have a bunch of 12V automotive motors at home (from work) but ideally I would use something better like a brushless motor for instance.

[@whatelseison8970]

I've often found you can get an idea of how good a DC motor will be as a generator by its aspect ratio. That is, short, fat motors found in things like tape decks and record players make good generators. Long thin motors like those found in power tools or automotive applications tend to be poor generators. If you want to get the best performance I'd recommend getting a bicycle generator for your project though.

[@sierraecho884]

@@whatelseison8970 I already found a stepper motor, they are way more efficient than a DC could ever be, but thanks.

[@axljayclordearta2005]

Sir can i ask? Whats the output voltage of the 2nd motor(supposedly the generator motor been used) is it ac or dc? Thanks 😊

[@tsbrownie]

At around 6 minutes you can see the chart I made for in / out volts, etc.

[@26apauapau]

I want to ask how do I prevent the DC motor from running from the battery ? I will make my dc motor like a generator Tap it into the battery or charge controller. What should I install on the system or line from the dc motor so that the electricity will not flow back to the motor?

[@tsbrownie]

Diodes are easiest.

[@1gurugraphics]

Well explain & good video. Thanks 😊

[@shahxaibghafoor4258]

sir i wanted to ask, if i manage to spin the motor without 2nd motor, will it work or not?

[@tsbrownie]

You can spin the motor / generator with wind, water, or whatever.

[@inspiring-minds01]

what if several D.C motors are driven by one motor ?

[@tsbrownie]

There is no free lunch. If I drove 3 motors, each would get 1/3rd of the power and would produce 1/3rd as much (best case).

[@davidhati4826]

Question: Can you charge your phone with this and if yes how many voltage fo you need for the driver?

[@tsbrownie]

It will depend on several things: 1) voltage of the motor (this will need to go through a regular to ensure it does not damage the phone), 2) current (you need enough current to charge in a reasonable time, but not too much as to damage the phone), 3) 1 & 2 will determine how big the generator is, and how much energy you need to turn it. You can always experiment on a old phone you don't care about.

[@sayori3939]

You DO need a 5v stabilizer and you probably won't make sufficient current eith these :/ if you manage to get like 1-2 amps you're golden and you probably need diodes to keep the energy from the battery to go to the motor

[@Gawdsqwad]

Will this burn out if it and a controlled voltage power supply

[@tsbrownie]

I don't understand. A motor will run at the rated voltage usually without the need for a current controller.

[@rayabad]

I’ve been wanting make an experiment on a solar panel to run a small DC motor to raise an object to covert the energy to potential energy then reverse the potential energy to electrical to lightup led lamps. This way we wont need batteries for storage.

[@452gerry]

I literally had the same idea. Have you had any progress? My first thought is how to connect the weight to the motor and generator. We should get in touch

[@syedsaudkazmi]

Nice Video, found this video because i want to use a small DC motor as a wind turbine to light up a few LEDs, 1 question where can i find small generators of the same size as these motors?

[@tsbrownie]

I've never found one. The things sold as generators have always been these little motors.

[@user-up9qb1sw6c]

hi if hi want one of those DC motor fi by how do hi get it

[@tsbrownie]

I bought these ar radio shack but they are common and available at electronic shops, online, etc.

[@ichhasseamerika]

What's an 'RO motor'?

[@tsbrownie]

It's the motor from an RO water filter pump.

[@markcope11]

I tried to use a similar motor spinning it full speed with a drill only produced 0.2 volts and it's a 9v motor maybe I'm not spinning it fast enough? I dont get it was going to use it as a mini wind turbine but 0.2 volts isnt worth it

[@tsbrownie]

A drill should spin it plenty fast. It sounds like that motor may be bad. You should get a few volts just spinning it with your fingers. Some motors have build in speed controls and if you overspin them they will cut out.

[@markcope11]

@@tsbrownie I took it out of an air mattress pump that has 6 1.5v batteries that was working I just never have batteries think I'll try a different motor

[@globleeboo4323]

Did you have to reverse the direction of the motor acting as a generator in order for it to work?

[@tsbrownie]

No, most of the smaller ones work well either way.

[@globleeboo4323]

Thank you! Also I have another question, how does the back emf of both motors affect efficiency? How does it work?

[@tsbrownie]

@@globleeboo4323 I have never seen nor consider the effects of back emf on efficiency. I've always worked to keep it from killing voltage sensitive components.

[@globleeboo4323]

I see thank you, also how did you connect the multimeters in the circuit?

[@tsbrownie]

@@globleeboo4323 I just connected them across the output. Not the best for measuring large watts, but usually OK for these small things.

[@samuelpaul01]

What happens when you use gear to increase speed on the generator motor

[@tsbrownie]

The generator will produce more output, but the motor will have to work harder to do it. It's like the gears on a bike.

[@mohabiraq1]

have u thought about using a or gears, i'm sure u would get better numbers

[@tsbrownie]

Yes, I tried it, but gears just add more friction, even with high quality lubricants.

[@occrc3333]

what about as a generator for a 1/8 scale series hybrid system? Like you would find in a Prius. Using a 12v lead acid. Do you think that there is enough efficacy to charge the battery using that system? Also loved the video, I still have much to learn in measuring input in output of electricity

[@tsbrownie]

I am not sure, but it would be interesting.

[@emil.honganmaki5461]

Prius 12v battery only for computer. it is not a starter battery Prius starts with a high voltage battery.

[@occrc3333]

@@emil.honganmaki5461 not the system exactly but the same concept with lower voltage

[@josedavidrodriguez]

great video !

[@crytobinance2957]

Hi sir but mine generate electricity when the motion is backward

[@tsbrownie]

That is not unusual for these motors.

[@kevins4736]

I would assume this throws the free energy down the drain. I see a lot of videos of free energy taking two motors one generating and the other for power. Nothing is free

[@tsbrownie]

I have reproduced some of those and they spin down so quickly you can't tell there was any help from the generator.

[@piotrr.1972]

Yep we need 4k video

[@nurdadone4063]

Hi there, I have a question what would happen if the generator receive significant higher torque than its capability? Would it be still generate electricity? What would affect the generator? I've got project, that generate quite big torque, unfortunately I only afford small dc motor, so I wonder if I could use for it Thanks

[@tsbrownie]

I do not understand what you mean by "higher torque than its capability". Torque is mechanical twisting. If you twist the shaft too hard, it would break. If you spin it too fast the insides will come apart and the bearings will go bad very fast. Plus the brushes would probably bounce and arc, causing them to go bad quickly. You can find free motors in many things, most of the ones I have were taken out of junk.

[@nurdadone4063]

​@@tsbrownie Thanks for the quick respond, got my subs. I mean, on the motor specs its only had about 0.8kg.cm torque capability, while my system generate about 150kg.cm. I've calculated, the shaft wouldn't break with those amount of torque(based on its diameter), my concern is about the electrical parts, will the motor still generate electricity? Or would it break because of it?

[@tsbrownie]

@@nurdadone4063 Sorry, I don't know.

[@jasonrench1456]

Its possible to burn it up creates more then what the wire can handle over heat due to friction. Possible solutions. Use cooling line wrap copper water line with radiator fluid around motor run through radiator of drive system if equipped step 2. Gear ratio. Use small gears to reduce speed 50 50 gear ratio.small gear on drive motor. Larger gear to generator.

[@johnlintorn6768]

Really helpful! Thankyou!!

[@steved6275]

I think you supposed to use a smaller motor as driver and a bigger motor as the generator??

[@tsbrownie]

Bigger and smaller, or gears, or capacitors... don't change the equation that work in must be greater than (or equal to in a friction free world) work out. It's the law... of physics.

[@RixtronixLAB]

Nice info, thanks :)

[@Totogita]

What would happen if a wind generator motor was turned by a small motor?

[@tsbrownie]

The total output power would be = to the input power - efficiency losses (friction, electrical resistance). But it might be interesting to use power to turn the generator when there is no wind and snow or ice forming to keep it from freezing up.

[@Totogita]

Well why wait for the wind I always say, if you need to increase current there should be a way. I have learned that some of the information given in school is to be tested to insure truth.

[@sumandevi9768]

Name of motor

[@tsbrownie]

No name.

[@prakashmudd7358]

put a gearbox for more energy

[@tsbrownie]

And more friction. No free lunch!

[@ParkChen-v7i]

Use gear for more effective

[@zero5374]

To bad you couldn't counter with a gear ratio.

[@mrtimos5046]

attach gears to increase speed of the generator motor 2 to 3 fold

[@kavero7274]

Bill gates is that you?

[@tsbrownie]

My lawyers said to say "no."

[@dannywilsher4165]

Not very efficient but very interesting!!!

[@tsbrownie]

Thank you. I've been wondering for a long time how efficient these would be, but could not think of a way to get a reasonable estimate. So yes, they are only good for non-serious projects.

[@wantdeal6507]

@@tsbrownie I think it's very efficient for working a white led

[@reikonr7173]

In places where no power it is life saver, a concept that can be improved depending in the situation

[@mehdihoseyni6352]

When it's 25% efficient, they should say it's -1/4 efficient When it's 110% efficient = 10% efficient

[@alanclark8342]

Considering efficiency can't be above 100%, it doesn't make much sense to write it that way

[@researchandbuild1751]

This doesnt make sense i thought electric motors tended to be 90% efficient

[@tsbrownie]

Not these little cheap motors, they are not efficient as motors or generators, but they are fun to play with.