Does a fast gearbox generate more electricity? 

As others have pointed out, you need to measure voltage and current at the same time. Also, when measuring current, your multimeter is set to mA, but your leads are connected to the unfused 10A sockets. This will give unreliable results.

This man sure does love his 3D-printed gearboxes

You need to measure current and voltage at the same time, NOT measure unloaded voltage and then multiply by the short circuit current.

You need a flywheel on the fast gear set to maintain speed and store energy momentum. For the big generator just get a slight faster speed and wala!

Getting the gearboxes to spin faster: mounting them with bolts/screws would be a great idea so you didn't have to hold them down for the spinning. This may look like a heavier-duty more industrial stand than what you've been printing, but that way, you could both get a faster and more consistent turn of the crank. And, speaking of the crank, if you increased the distance between the crank shaft and crank handle, you'll have significantly increased leverage, and thus an easier time to spin quickly and consistently. Seeing a metal gearbox would be fascinating. It would be a great way to compare the friction outputs of similar gearboxes with different materials; not to mention spin speed and electrical output differences.

Great video! But unfortunately as others have pointed out, you didn't measure power correctly. It doesn't look like anyone has explained how you should really do it, so try this: You should buy a power resistor. A 100 Ω resistor rated for 25 W would work fine and only costs like $5. BTW power resistors can also greatly exceed their power ratings for short periods of time, so it's fine if you produce over 25 W. Once you have it, connect it to the output leads of the generator, and hook up your multimeter to measure the voltage across it, and do some simple math. If you have a 100 Ω resistor and see 12 V across it, then you know your current because 12 V ÷ 100 Ω = 0.12 A. You'll also know how much power you're generating because 12 V × 0.12 A = 1.44 W. Good luck to you! PS. I don't know if you'd be interested, but I have a bunch of experience in 3D printing entire electric motors and have dabbled into 3D printing magnetic gearboxes. It might be cool to collaborate on something.

Nice work on the gears, looks like you've stepped things up a lot in how you've designed/put these gears together. Question though: You're measuring the voltage without load, and the current is being measured with the meter acting as a dead short.

3:27 if you are wondering why he doesn't just hold its handle. it's because for some reason when it's connected to something it's meant to power it becomes extremely difficult to move and feels almost impossible to get a good grip on

i have been wondering this for ages thank you so much im gonna subscribe since you did this.

You need to do comparisons on a standard load not just the open load voltages or currents. Although its ok for simple scenarios. You can also start with the law of conservation of energy or just the fact that if gear ratios increase or decrease speed, they do the inverse for torque.

A fun little test. and thanks for that, I really like your videos. But it just does not quite work out in reality. You will need to measure the energy you are getting into the system at the same time to get an idea of the output. And you can not measure voltage and amp separately, it must be done simultaneously with 2 multimeters. In the test you use 2 different generators, it will certainly also give different results. Suggestion: how about setting a motor to drive the input shaft, use the same generator at different gears, measure amp and voltage simultaneously.

That makes sense from a mechanical perspective as well. If you're riding a road bike, you can pedal the smaller gear ratio a lot faster to pick up speed and get going, and the big gear ratio, while requiring much more force, outputs a lot more power.

Thanks for this!

As someone who rebuilds industrial DC generators for steel mill conditions, I can tell you that most of the MG sets run at 1200-1800 rpm but I have seen some slower. They have a synchronous motor (an AC stator with a DC rotating field element that maintains a consistent speed without slippage) coupled to several (separately excited or series excited) DC generators on both ends of the motor. There is a direct mathematical relation of work done in HP to the output voltage and supplied possible amperage output. Horsepower = Torque x RPM / 5,252 and 1 HP = 745.7 Watts. Knowing this, you can deduce that the rpm can vary but what really leads to a higher output is the torque in the system. You can build a DC generator to maintain a certain EMF at variable rpm by adjusting of your excitation field in response (the bread and butter of series excited generators) but the actual amp(flow) output under load leans more on the torque of your driving force. AC generators are a completely different beast and are more dependent on RPM over torque with the speed being the deciding factor in the output frequency. Most run at 3600+ rpm with 3600 being more common in the United States in order to make that 60Hz frequency.

On that high speed gearbox, you need a bushing on the crank handle hole. This will spread out the forces, prevent enlarging of the hole itself, and make for a more secure crank handle. A bushing and bearing would work even better, but as we see in the video, even trying to use that crank for only a short bit wallowed out the hole it was in.

You should try covering the gears with magnets and surround it with a lot of copper wire to make your own generator

Nice work!

2:05 You are using your multimeter in 2mA range, so you arent getting 200mA from that motor, you are getting less than 1mA (0.234mA), and 2:43 you set it into 20mA range, so from that bigger motor you are getting 2-3mA - barerly to light up an LED, you can connect LED and see how much power you are really generating. For generating power purposes you should always use brushless DC motors, because they use permament magnets

Saving this for the power comparisons, but would still like to see the gear stack work on the large motor

So amazing video and explaining

Somthing that would probably help you is getting a solid surface you can turn better plus use triangles to help with the turnes and make the gears closer together

3:58 love this he already knew all his views have common electrical sense

I was looking at this as a means to make a gravity "battery" more efficient, as in needing the weight to fall more slowly, thus decreasing the distance it has to fall. Over a certain weight, the torque would be irrelevant, for all practical purposes. A flywheel might help even further, though it might not be necessary.

Multiplying Voltage with nothing else connected by short-circuit current does not yield achievable output power. You will have to attach a decent load resistor and measure Voltage AND power under that load. What constitutes a decent load depends on the specifics of the generator. If you don't have those specifics, measure it's resistance while it is stationary and use that value for the load resistor.

may I know why you still avoid planetary gears for this gear up ratio ?

Better bearings would greatly narrow the margin between high speed low torque, Vs. Low speed, high torque. The gears themselves, look really good. If they spun on precision ball bearings, that would reduce the losses of going through that many stages. I would start with a good crank bearing, since that's the one that takes the most severe radial load. making the axle longer, to put space between the bearings, will make them more stable against the cantilever loading caused by turning the crank by hand.

generators have a perfect speed at which they have the highest productivity, but the input energy also matters - the harder you crank the handle the more power you put in, but lots of gears invite a lot of friction, which is power lost. Makes sense a bigger generator will be more productive. When you hooked up to measure current, the multimeter became a load, and that resistance of the generator was the effectiveness of converting input energy to current. The small one didnt give much resistance, which means its not an effective generator.

Soooo which one can charge my phone?

2:22 when you dont use the handle, and create a false reading

What would happen if you were able to drop a weight from a height as input to drive the crank? Already out of my wheelhouse ...would adding a capacitor after generator help to reduce the start force needed?

Das pretty sick man.

Do it! Do a metal version of this!

Great description! Finally someone addressed the power vs speed principle

Anyone who knows a bit about friction knows the answer up front. Still a nice Video

Damn, the devs knew what we would try to do. We will find infinite power!

Well, you need to connect a voltmeter and a currentmeter together since the open circuit voltage and the loaded voltages are diffetent. And also when the probe is in the 10A range, switch the meter to 10A range.

2:50 "When you're measuring current [amps], there's a lot of resistance in the motor." I've been using a multimeter my whole long life, but I don't remember ever reading this in the instructions. In fact, Googling text instructions about this produced nothing. It was only when I looked for video instructions on how to measure generator current that anyone mentioned this. Learn something new every day! 🤔

I'd be interested to see you use a higher gear ratio for more spins, attach the bigger motor, extend the handle way out at about 75°, then add a heavy weight at the end. The handle will only turn roughly a quarter but the spins a power generated should be high.

Nice 👍

One flywheel added on motor rotor and make last spike wheel gear with one direction free rotation mechanism will provide greater afficiency

I would like to see a full metal version of the gearbox

Make the gears from metal!! That would be great to see

seems like, for this to be a fair comparison, you'd have to use the same alternator for both setups. different sized alternators will have different efficiencies.

May i suggest adding small heavy flywheel to start the first momentum and help for the next momentum

4:20 He clearly is a cultured man.

You need to calculate watts with a resistor in line because the voltage will drop some so if the 12v drops to 6v that's big or if the 3v dropped to 2 or 1

the speed to power generation potential of your gearbox will directly correlate to what kind of induction motor your using, if your using a high RPM low torque motor then high speed will work better but if your using a low RPM high torque motor the opposite will apply, that's why they use high torque for water turbines and low torque for wind turbines

In theory, yes; theres a major increase of torque required and on top of that quite a bit of energy is lost to friction and entropy.

hi, what are your dimensions of the gears? for a science project :) thx

Its interesting, in general we could describe de open load voltage of a CC machine in terms of speed and exciting magnetic flux, for permanent magnets we could say that the magnetix flux is going to be constant, so your open load voltage is going to be speed dependent only. Besides that the amount of mechanical power you inject in a system is equal to torque times rotational speed en rad/s. You have to consider that the amount of mechanical power wasn't exactly the same for both cases. Whatever it was a nice experiment though :) .

What if you designed a small custom motor that is specifically designed for the small and fast gear setup? You did mention the coils and magnets play a big role in current generation so perhaps making an hybrid motor will improve the output?

You can just buy metal gears from SDP/SI and it would be a lot cheaper than 3D printing them.

I love how the video ends at 4:20

i instantly know the big one should be better if you have the same watts of input bcs of the resistance on the gears

you can put motor at the input so you can generate big volt on output (generator)?

Instead of a hand crank could a heavy weight on line that unravels as it falls (slowly due to the resistanceof the gear ratio), maybe the height of the room for prolonged duration?

I see the handle is very loose on the fast gearbox, making it metal would be a good decision, if you oiled it.

I imagine that you could run quite a few small generators on that setup though. I'm curious how many you could fit and what those numbers would look like.

Yes, please make the solid version.

there's a problem in your calculating . When you measure the voltege across the motor , the internal impedence's motor is zero. Because it's like an open circuit (the impedence of a multimeter has to be very high, in this way the current flow is almost zero). So you can get an accurate voltage's value. But when you connect the motor to the tester, for measure the current, in this case the impedance of a tester is almost zero, so the motor sees two impedances, that of tester and internal motor. You have so a drop voltage that you're not considering.

i think bearing will help to use handle and improve the stability and use it insted of manual pusing gear using hands

Does it matter which direction the generator is turned? If it was turned in one direction for an hour & then the other direction for an hour, is there are generator that would work in both directions?

Any generator will provide more electricity if driven at a higher speed but there will be an optimal speed above which the output will begin to fall as mechanical and electrical losses increase. The losses will appear as heat.

Do you carry out live streams?

You should try this with planetary gear sets

He can try using the power outcome of the gearbox to spin the gearbox.

Try increasing the length of the lever for more of that sweet, sweet, leverage.

Try making the crank longer, thus you get more torque

Nice

No. It's about how much power you input into the gear, minus the friction loss, times the efficiency of the generator.

If you make a model out of metal try to get the tolerances as tight as possible

You should make a self cranking gear box for you to bypass cranking it yourself

Better to connect the motor wires to a known resistor, then calculate power via: Power = (Voltage^2) / Resistance

4:20 vid length. Nice

Use ball bearings from rod to gear, for smoothening the spin

Can you explain how to start 3d printing from scrach.

Can you like make gear box like this which like makes the last gear spin soo fast that in a hour atleast you can power up your whole house for 10 minutes, it would be such a energy saver

As a control I think he should be using the same generators for both gear ratios. Metal and nice bearings will help so he can crank of them as hard as he wants

Do a full metal one

Please put up where you got the big generator

What would happen if you swapped the gearboxes though? Which would make more power then?

The short answer is yes, unless it has a voltage regulator on it. Because otherwise a alternator would create more voltage as rpms increase, but it doesn't create more than 14.?? Volts at any given time.

Ahhh time to make a toast *spinning intensifies* Toast pops YEEEA

Could an unwinding spring be used to automate the crank for some time? A big, strong spring like the ones used in garage door openers? And for that matter, wouldn't increasing the time it takes for the first gear to revolve once (maybe by adding gears to the system then compensating for the added necessary force with a stronger spring?) mean that the spring would take longer to unwind, thus elongating automation? How far could that be taken? How long could an unwinding spring automate the system? If it could. I'm no engineer and I'm sure the nature of my questions reveal my ignorance. But I thought it seemed like a simple enough mechanism with potential.

which 3d printer do you use?

Great gear builds. Too many variables at once tho. You change one variable at a time while doing the scientific method for accurate results.

Add a flywheel to your design so you can produce the torque you need to push the big generator

Your multimeter looks exactly like mine.

It's simple the RPM must be above the motoring speed such that it goes into generating mode.😎

Apply a significant load and there will be great difficulty keeping up higher RPMs.

make a big size gear box that can generate torque enough to rotate the big generator

Did you measure the force applied ?

*sees video length* Nice

I think you should use small motor for volt and big motor for amp to make good generator😀

Which motors didi u use

If you are up to the task you can DIY a foundry and cast aluminum gears with sand

Do a metal version pls

This confirms that size does indeed matter

On top of what others have pointed out, have you made sure you're inputting the same amount of wattage into each system? Sure, the small one produced less, but how do you know this isn't just because you were inputting less energy?

Please do the metal one