Mostly Permanent Magnet Motor with minimal Input Power

[Khwartz]

Hi Luc, an all.

I come back on this post of you, Luc, for MH.

Hi MH,

Today I found there is a difference between the coil connected in parallel vs series.
In today's tests the best efficiency results for the coil to move up against gravity was with it connected in series. However, I think the gain could be mostly from the boost in Inductance. Gyula suggested a way to measure the Inductance and the results are 8mH vs 30mH in series. So I think this would need to be considered.

indeed, as inductance expresses the ration of magnetic flux, in Webers (Wb) against the current flow in Ampers (A). So this is a kind of efficiency ratio. Higher the inductance is, higher is the magnetic flux will be for the same current. (But you probably know that ).

The problem, as I see it, is that inductance goes much with the number of turns.

You want to increase the number of turns to have better inductance but then you get, if same wire section in mm², a higher resistance if you increase the length of the wire in the same time.

Then, it may be ask what would be the optimum solution.

One can increase the voltage for example, to compensate the higher resistance.

As a matter of fact, there is no analytical formula for now, which allows to get the answer in terms of length of wire, number of turns, length of coil, inner and outer diameters. Only formulas exist for specific configurations.

I have worked these days on a spreadsheets and I have tried to test each characteristic, against an efficiency ratio I made: FLUX under INPUT POWER; which is, imho, the very ratio we need to work against.

The first results I have on a specific formula are, that the efficiency (having all the other factor maintained constant):

1. drops with voltage (very at the opposite I was thinking! ^_^)
2. doesn't really change with the inner diameter
3. drops with the wire diameter (because it change the outer diameter?)
4. increases with the number of spires (remember: all the other factor remain the same, so for a same wire length! will mean shorter coil...)
5. increases with the number of layers (which is equivalent to a shorter coil).

These are in my opinion important data to check and know to go in the right direction of researches and suggest that pancake coils would be the most efficient by this ratio.

Nevertheless, it should be noted that the flux here is gotten through the whole section of the coil while it is not necessarily what we are looking for in we want to concentrate to flux in the core of the coil.

BTW, all these results were for air coils.

Today's tests
All tests done with low voltage.
To maintain a stable low voltage through the coils power stroke, I used a 650F Super Cap fully charged and stable at 2.7vdc 
By using this low voltage the coil moves up slowly and resulted in less losses as these were the most efficient results to date.

so, this looks to verify my result number 1.

Using the coils maximum upward travel stroke of 23.5mm it used 1.2J connected in parallel and 0.94J in series.
If we use the 0.94J and we subtract 0.54J which would be the unity amount needed for the coil to travel 23.5mm (if my calculations are correct?) then we are left with 0.40J under unity.
However, by having the coil travel to the maximum height I was able to collect (in another cap bank) 0.32J as the coil fell back down with most speed.
So if we deduct that we are basically 0.08J under unity.

Very Great you had, Luc, the idea to make this calculations 

So it looks like at best around 90% efficiency.

No so bad

Now that it's confirmed the device is Under Unity, can you please help me to rate it as it's ideal work solution, a Solenoid.

I would need some of you guys, make systematic tests of different kind of coil so I could analyse it and produce a spreadsheet able to give the optimum coil in any case against any factor.

I have work indeed on existing formulas but I am not too confident in their behaviour compare to the reality, especially when we try to push a factor towards a certain limit. But seeing how many of us work with coils, I think it is most sad not having any real complete tool to calculate and predict the ideal coil for a specific use. We could work together all here on that research. What do you think here guys?

There must be an established protocol to test Push or Pull force vs power

Maybe, but remember they are not same kind of quantities cause FORCE missing the TIME DIMENSION and even the LENGTH DIMENSION. I remember you power goes with A MOVING FORCE IN A CERTAIN LAP OF TIME.

If you don't care of the time, then you deal with ENERGY, while ENERGY [Joule] = FORCE [Newton] * DISPLACEMENT [meter].

But you may indeed make yourself a ratio of power consumption against the pulling force of your coil as you have already done several times.

and stroke to rate the efficiency of a Solenoid as I've found charts in some solenoids pdf data (see below)

This would be of most help

Thanks

Luc

The protocol is just what you do: measuring pulling force against electrical input power, and for torque: not forgetting to divide the pulling force by the radius of the application point of the dynamometer.

[gotoluc]

Thanks Khwartz for your interest and posting your ideas.

Looks like no one knows how solenoids pull charts are done or they are not interested.

If OU is not a possibility or claimed, people are just not interested, even those who believe OU is not possible.

Luc

[synchro1]

I'm drowning in pink, what gives?

[MileHigh]

Well nobody ventured an idea when I said that the variables being tracked for Luc's experiment were wrong.

Luc was quoting pull force per watt of consumed power.  What is wrong with that?  Well, I will use hypothetical data as an example.  Let's say that it's 10 watts for 100 grams of pull force.  Then we keep the same identical setup except we change just one thing.  Let's say we increase the diameter of the wire slightly, say from 32 gauge wire to 24 gauge wire.  You repeat the test and now you get 7.5 watts of power for 100 grams of pull force.  What conclusions can you arrive at after looking at that data?

For the commercial solenoid, Luc posted diagrams from the manufacturer that showed pull force vs. distance for different power levels.  Why is the manufacturer posting that data?  It's taken for granted that the higher the power you put into the coil the more pulling force you will get from the solenoid.  So what is the REAL reason for the manufacturer to post that data?

[phoneboy]

@gotluc, might help??