Luc:

It's a very nice build, but you are dealing with essentially the same issues as were seen in your generator clip using the Dremel.

The efficiency of the drill press is unknown.  So you have about 150 watts of power consumption and about 5 watts going into the load resistor.  It's simply too difficult to know how many mechanical watts are going into the rotor because that is "buried" in the unknown efficiency of the drill press setup.  One thing that we do know is that the faster electrical motors run, the better they tend to perform.  That likely explains your observations when the drill press runs at a higher RPM.

When you disconnect the load resistor the power draw of the drill press goes up.  When current is flowing through the generator coil, that reduces the cogging.  We see from the beginning of your clip that the cogging is very strong.  When you disconnect the load resistor you actually hear the cogging kick in.  That's the main reason the power draw increases, because of the nasty cogging acting like a disturbance torque on the motor.

Note that you have two conflicting trends.  When you add a load resistor in theory the power draw from the prime mover increases.  In reality that does happen.  But at the same time, adding a load resistor results in current flow, and that reduces the cogging resulting in a decrease in power draw from the motor.  Even though in theory the cogging is energy-neutral, in practice you can literally hear the increased stress on the system when the cogging is happening.  These two conflicting trends make it nearly impossible for you to get the real data that you are looking for.

So, you can make measurements, but between the unknown and variable efficiency of the drill press setup, and the conflicting trends of adding a load resistor and at the same time time decreasing the cogging, it will make it essentially impossible to extract any useful data.

Note that Thane Heinz's experiments suffer from a similar problem.  The power inefficiency of his transformer setups is ignored and he just focuses on his differential power measurements.  He ignores the power inefficiency that does nothing more than produce a lot of waste heat.  His differential "efficiency improvements" are buried by all the inefficient waste heat being produced.  The waste heat is always larger than his actual power measurements.

So what is the solution?   I certainly don't know the best solution but I do know a tried and proven solution.  It's the same old thing:  If you had a big flywheel on a very good bearing, and you knew the moment of inertia of the flywheel, then you could use that as your power source.  Doing this completely eliminates the unknown efficiency of the drill press setup.  When the flywheel drives the rotor you can make a precise measurement of its deceleration.  Then you crunch the numbers and calculate the mechanical power being output by the flywheel for various test setups.  If the flywheel is large enough, then you will not have to worry about the cogging at all.  The energy-neutral cogging will not affect the flywheel like it affects the motor.

Perhaps somebody has a better idea, but the only way I can envision extracting real data from your tests is to do flywheel spin-downs.

MileHigh

Excellent posts MileHigh!

I appreciate your effort and honest opinion. I'm sure if we all work together in a supportive way to better understand how to best test and deal with this kind of effect we will get there.

You mentioned flywheel, how about I add a flywheel above the C core?... would that not smooth the cogging so we would get more stable power readings?

To everyone else, please share your thoughts on a way to obtain reliable power measurements of such a setup.

Regards

Luc

Here are two test i did with this flux gate generator setup using 2 ring magnets...

Here is one test setup with 1 small coil...
https://www.youtube.com/watch?v=B1FavPfg_Tc&list=UUNk6nZuUrTLRnp__hAgAqjw

And here's another test i did with a longer coil...
https://www.youtube.com/watch?v=m_rP9Pf2IeU&list=UUNk6nZuUrTLRnp__hAgAqjw&index=2

The reason i'm placing the coils on the edge is that there is the spot for the most output...

Man,that rotor anf flywheel are that well machined i can hardly seem them spinning lol. I see the woodwork is stil up to scratch TJ

Im looking a lot deeper into this delayed magnetic field effect,and as you will see in my next video,i have an induced magnetic field that comes from !i dont know where! lol.-Advanced and delayed magnetic fields will be my new topic-watch for it.

Luc:


The efficiency of the drill press is unknown.  So you have about 150 watts of power consumption and about 5 watts going into the load resistor.  It's simply too difficult to know how many mechanical watts are going into the rotor because that is "buried" in the unknown efficiency of the drill press setup.  One thing that we do know is that the faster electrical motors run, the better they tend to perform.  That likely explains your observations when the drill press runs at a higher RPM.


MileHigh

Dear MileHigh.

With respect, your statement above is incorrect.

On all but the most sophisticated Drill presses the drive motor's shaft speed remains near constant. Spindle speed change is effected by changing the drive belt ratios under the top cover.

Cheers Grum.

PS. There are also three rather nifty flywheels already built in !!  In the form of the Cast Iron multi stage pulleys. 

Tinman noted:

Im looking a lot deeper into this delayed magnetic field effect,and as you will see in my next video,i have an induced magnetic field that comes from !i dont know where! lol.-Advanced and delayed magnetic fields will be my new topic-watch for it.[/size]

The "delayed magnetic field effect" and induced B fields are of great interest.  Looking forward to your vid.

Now let's look at the case where the there is a generator coil with a core, but there is no load resistor.   In this case, the rotor magnet is attracted as it approaches TDC of the generator coil and that's a pull.   When the rotor magnet passes TDC you get a push.

So in this case, you get a "pull-push" type of cogging.  This is in theory energy neutral.

In Luc's case, it's a "big-pull-big push."  This stresses the rotor and the stator assembly and you get mechanical hysteresis losses.  In other words it's like bending a coat hanger and the bending point gets hot.   However, my gut feel is telling me the main source of the losses are in the motor itself because the motor does not like being yanked around by the big-pull-big-push.

In Luc's case, when he disconnects the load resistor while the drill press is running you clearly hear the "thwack! thwack! thwack!" of the big-pull-big push cogging.

So why does the sound of the cogging go away when Luc's connects the load resistor?

In this case you have two things happening at the same time, the cogging from driving the load resistor and the cogging from the attraction to the "core."

From the load resistor:      big-push-big-push
Form the core attraction:   big-pull-big-push

The net result:                  "cancellation"-bigger-push

In other words, the Lenz drag from the rotor approaching TDC, and the attraction of the rotor to the "core" tend to cancel each other out.  This cancellation effect tends to mitigate the cogging.   Even through past TDC the Lenz drag and the rotor attraction add up and produce a bigger push, it's still a "smoother ride" for the rotor will less overall disturbance happening.

Your ears give you the reality check.  It's very obvious that the "thwack! thwack! thwack!" gets much louder and the electrical power draw of the drive motor goes up the moment Luc disconnects the load resostor.

MileHigh

Dear MileHigh.

With respect, your statement above is incorrect.

On all but the most sophisticated Drill presses the drive motor's shaft speed remains near constant. Spindle speed change is effected by changing the drive belt ratios under the top cover.

Cheers Grum.

PS. There are also three rather nifty flywheels already built in !!  In the form of the Cast Iron multi stage pulleys. 

That's an excellent point.  In looking at Luc's clip it looks more likely that there is a belt drive for the drill press.  So I may be wrong in my earlier comments about this.  Another thing to consider is that the with the drill chuck assembly plus the rotor spinning at higher speed, there is more rotational inertia and so you are possibly back with a "smoother ride," especially for the motor itself.  Perhaps that partially accounts for Luc's observations at higher speeds but I am really not sure.

MileHigh

P.S.:  TK thanks for the vocabulary lesson!

Yes MH, the drill press is belt driven and not a direct drive. To change speeds you have to physically re-position the belt on a different  pulleys size. See pic

Thanks for your new update due to this fact

Luc

Good to clarify this.  My micro drill press has both a variable speed motor control and the 3 position stepped pulley arrangement.

Bill

Hi everyone,

as some of us have been suspecting the higher RPM seems to be storing magnetic flux in the core and possibly if it has no where to go when coil is not under load it discharges or causes a braking effect when the C core changes phase which may be the slaps sound we hear. When the coil is on load the stored flux gets out so the C core makes it through to the next phase with ease.

Here is a test example of the prime mover input power when the drill press is at medium RPM range.

120w just turning the C core with I core away
140W with I cores in position and coil not on load
135W with coil on 1 Ohm load and delivering 5W to load.

So there's 10W which is not accounted for and it's hard for me to believe that so much power is being wasted in such small cores as Eddy currents and heat losses. At lower RPM there is less losses but also less output. It all seems to be linear and under unity.
If we could come close to a break even point I would say we are on the right track but it's not looking that good at the moment.
I have tried different load values, RPM's and so on but there is always losses.
I will still try different combinations and give an update if I find something better.

Please keep in mind what I'm testing is a variation of the original idea shared in this topic.

Luc