Two dynamo electric motors connected via the axes
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- Опубликовано: 29 сен 2024
- In this video the same motors of the other video are connected, by coupling the axes, it is noted that the current absorption is higher than the transmission with magnets.
The other video: • Electricity generated ...
Power is what's important. Measured in watts it is calculated using volts * amps. Comparing amps on one side with Volts on the other doesn't tell us how much power is involved. Multimeters are $10 each so for $20 you will be able to fully characterise this circuit by measuring amps and volts on *both* sides.
While I agree it would be straightforward, if you use some deductive reasoning, you'll find the system to be adequately defined.
Your original claim was in favor of the direct coupling: " The losses due to friction would be the same (or better?) and energy losses would be smaller."
We see that for the same setup, output voltage remains the same and input current was reduced (1.74A for magnetic coupling, 2.24A for axial coupling, 29% difference in current).
LED bulbs are constant current driven, so at the same voltage we should expect the same power draw. These lights are 5W 24V rated. Assume 80% power conversion efficiency.
The battery will be 12.6V open circuit and 12.2V loaded at 2.24A because the datasheet for the battery says so. Therefore, the battery draws approx. 21.3W in the first instance and 27.45W in the this instance. This also implies a 29% power difference.
If we are to assume that the LEDs are exactly drawing 5W each, including losses, then the output always draws 20W.
Therefore, this means the losses between the two motors in the first test was 1.3W, leading to a conversion efficiency of 94%
Lastly, in the second test, the losses from the direct coupling were 7.45W, therefore, the conversion efficiency was 73%.
edit: formatting
@@Infinion you are making guesses and assumptions. A couple of multimeters is an easy way to *accurately* measure. The fact that you think the battery is a certain voltage shows your total lack of understanding. Try measuring the voltage on a battery over time before wasting time on a keyboard.
@@wd41 I know the battery is at a certain voltage because I looked that voltage up in the datasheet for the given C rate discharge of this model of battery clearly visible. Come on man, seriously? The information is at your fingertips.
@@Infinion - We do not know if he topped off(charged up) the battery for the second test?
@@imaginarypoint That's true, so lets quicky entertain the possibility that it wasn't recharged between tests. We'll take some measurements and see how much of the capacity was used and whether this would have significantly (greater than 5%) changed the voltage in the second test.
estimated Battery Ah consumed in test 1:
0.55A for 20 seconds
0.6A - 1.7A transition for 10 seconds
1.74A 20 seconds
1.7A - 0.55A transition 5 seconds
0.55A for 17 seconds
0.6A - 1.7A transition for 12 seconds
1.71A - 1.65A 32 seconds
1.72A 15 seconds
1.7A - 0.55A transition for 3 seconds
0.52A for 14 seconds
0.55A - 1.67A for 14 seconds
1.68 - 1.62A over 43 seconds
*Calculation: *
remembember 1 amp multiplied by 1 hour = 1 amp-hour or 1 Ah
1 amp for 30 minutes = 1*30/60 = 0.5Ah
adding it all up (remember 3600 seconds = 1 hour) and feel free to plug this into google sheets or microsoft excel:
sample:
0.55*20/3600+average(0.6,1.7)*10/3600+1.74*20/3600+average(1.7,0.55)*5/3600+0.55*17/3600+average(0.6,1.7)*12/3600+average(1.71,1.65)*32/3600+1.72*15/3600+average(1.7,0.55)*3/3600+0.52*14/3600+average(0.55,1.67)*14/3600+average(1.68,1.62)*43/3600
The result: 0.073 Ah consumed out of 5.4Ah, this is 1.35% of total capacity.
Since the second test is discharging at 1.7A/5.4 = 0.41C, we can follow the discharge curve in the DJW12-5.4 datasheet for the battery.
Since the previous test consumped approximately 0.073Ah, this would place the starting discharge at the 2 minute vertical line intersection in the graph. If we compare the voltage at this point to the time = 0 voltage for this discharge rate, it appears there is no voltage difference.
How long would the first test have to run for for there to be a significant difference in battery voltage? According to the discharge curve, longer than 10 minutes at 0.4C would have the battery voltage transition from a constant voltage region to a region with rapidly decreasing cell voltages.
Conclusion: it's safe to assume that the results would remain accurate whether Robert33 charged the battery between tests or not. As long as the test is being done in the constant voltage region of the battery discharge, the calculation is accurate.
This was used almost since 100 years ago when you needed high voltage ~200V DC from a 12V battery in order to supply tubes. It was called a Dynamotor and was mainly used for military and avionics. Car AM receivers had to use a device called "Chopper" which was a relay that turned on and off many times per second. They were a lot less reliable than Dynamotors.
Nice video, and a surprising result. The fact that it appears to show a direct coupling to be less efficient than the previous eddy-current drive, really goes to show how deceptively complex this apparently simple system is. It's easy to make lots of apparently logical assumptions which turn-out not to hold true in a real system. Here are a few potential gotchas:-
1. The efficiency of the motor and dynamo will vary with the speed they run at. The dynamo is running faster now than it was before. The load appeared to be quite well matched to the dynamo speed before, so it's likely that there is a mis-match now and the dynamo efficiency is much lower.
2. Making an efficient mechanical coupling is possible, but not particularly easy. With two shafts end-to-end like this, alignment is super-critical to efficiency. Various couplings are available to help make things easier.
3. Without measuring the load current, we can't really tell how much power is being used by those "5W" LED bulbs. They are a complex system in their own right. Their power draw when over-volted like this could be very un-predictable.
Thanks for the comment.
This is just a video made in a few hours, practically having to do precise things, you should evaluate many factors, power calculations, frictions and other tests, which can only be done in a technical laboratory.
Roughly 29% less efficient than the magnetic coupling (2.24A vs 1.74A on input), very cool!
@@Infinion Sadly, you can't conclude anything about the efficiency of the coupling from this test. You can say that this *whole system* is running less efficiently than the other *whole system* , but that's about as far as you can go. Way too many things have changed from one setup to the other and they're all inter-related. The fact that the "conclusion" is so counter-intuitive should ring all-sorts of alarm bells about how solid it is.
@Colin Stamp, perhaps it is better that you express yourself more understanding, if you have to make some negative criticism that does not convince you of the authenticity of the video, you can write it.
@@ElectricExperimentsRobert33 I don't have a problem with the authenticity of the video. I'm sure we can take everything in it at face value.
The only problem is when conclusions are drawn which the evidence from the experiment doesn't support - namely that eddy-current drives are more efficient than direct mechanical couplings.
What the video shows is the motor drawing more current than in the previous setup. That is all. There are a number of important things it *doesn't* show. For example:-
How well set-up is the mechanical coupling? They can be made nearly lossless, but it needs some care.
How has the motor efficiency changed now it's running at a different speed and with a different load?
How has the load imposed by the LED bulbs changed now the dynamo is running faster?
How has the dynamo efficiency changed at the new speed and new load?
The video is a nice demonstration of voltage convesrion done the old-fashioned way, but it shouldn't be used to infer anything about the efficiency of different coupling methods.
If you put the proper polarity magnets on each opposite side of the motor case opposite polarities it will gain speed.
Здорово!!!!!
SHOW
So cool how you can hear the motor slow down when the load is applied to the circuit.
So direct coupling uses more amperage, is it due to the lack of leverage. It seems the other video you coupling used the lever effect. You should make another video with a larger copper disk and longer lever on the driven motor and see if it is the mechanical leverage or the lack of direct coupling that is making it more efficient.
Nice one, would be interesting to see, bulbs hooked to battery's side, and see power draw required , then hook to 2nd motor drive for comparison.. very interesting... Have thought about placing external magnets on motors cases.. seemingly get more power from the surrounding, Thom in Scotland.
Większe obciążenie niż na neodymach Brawo za poświęcony czas i pieniądze, eksperymenty kosztują
This should create hella free electrons. Enough of those is called electricity. Your a genious.
Your missing the post of the direct connection AND the spinning neos.😢
this is a good demo to show how a mechanical inverter worked...using 12 volts to step up to 24v through mechanical means to drive an appliance
yes that's right..
@@ElectricExperimentsRobert33 🐱👍🏿
@ElectricExperimentsRobert33 can I ask what happens if you put mechanical energy on two dynamos at the same time, can you combine their electrical outputs for a stronger result?
Gracias Roberto!! Buen vídeo.
HEYYYY!!! I have the same multimeter!!
Nice demo here! What are the odds Elon Musk is already working on a vehicle that charges itself? The "PerpMobile" maybe? ✌🤣
Is this better than the magnetic coupling (previous video)? I see more AMPs taken from the battery with same VOLTs in the output...
Good question. We don't know if the batt was re-charged for the second test?
For this specific setup with this specific load, and these dissimilar motors, the previous setup is more efficient. If identical motors were used, maybe this rubber coupler would have less amps than the eddy current coupler in the previous video.
@Imaginary Point in the comment thread with WD41, I calculated if this would play a significant role in the test. It did not.
I believe the takeaway here is that the previous setup act as a coupler with slip. This works like a speed reducer and allows a motor with a lower operating speed to run at a more efficient operating region, so the gains from motor efficiency outweigh the heating and magnetic losses by a large margin.
@@Infinion "..I believe the takeaway here is that the previous setup act as a coupler with slip. This works like a speed reducer and allows a motor with a lower operating speed to run at a more efficient operating region, so the gains from motor efficiency outweigh the heating and magnetic losses by a large margin..."
Yes! agree 100%. This is good stuff.
Experiments Robert33
2 years ago
234K subscribers
Thanks for posting 👍
Hi good test
i need to re establish the lathe panckake motor with washing machine dc motor with more multimeter voltage and amp reads please
excellent
wtf
нужно на скутер прикрутить чтоб заряжала аккумулятор 48 вольт
Still, there is always power loss.
In all the ways known so far, there is no system that there is no loss.
@@ElectricExperimentsRobert33 That is true, however we try to minimize wear too. Imagine if this had to work for 24 hours per day 7 days a week how much maintenance would it need, not to mention space and noise. That is why Inverters are used, cheaper to operate. It's nice to display the principals of operation or conversion but in the end the real world needs something with low cost of operation.
This video is just to highlight the mechanical versus magnetic efficiency I did in the other video, nothing more..
@@ElectricExperimentsRobert33 - Was the battery charged back up for test#2?
Conect 2 extra wires back to batery to recarge it same time ..
Not sure what this is demonstrating…
That by using the eddy current coupler shown in the other video, the motor draws less current when the same load is applied.
a mechanical inverter...using low voltage to step up to higher voltage mechanically to run a set of appliance
@@fidelcatsro6948 👍
I keep looking at both experiments and I'm still not convinced that the magnetic shaft is more efficient than the direct one. You really need those cheap 4usd ammeters(with both V and I showing) so we can see in real time the current for input and output.