F.B.D.I.S.S.M - Flux.Boosted.Dual.Induction.Split.Spiral.Motor.

[Honk]

Sticky Spot force update:

I replaced the 25mm deep solenoid with a 12mm deep (shorter) solenoid.
It has the same type silicon steel core as the larger one and same face dimensions.
I used the same 160W input power when activated.

Test results when moving the lever from the Neo into the 12mm Solenoid area:
No power and no added backing neo     = 7.2kg force. (25mm Solenoid = 6.5kg)
No power but added one backing neo    = 5.8kg force. (25mm Solenoid = 5.5kg)
160W input and no added backing neo  = 4.1kg force. (25mm Solenoid = 3.2kg)
160W input but added one backing neo = 2.4kg force. (25mm Solenoid = 1.5kg)

As you can see the results became worse when using a shorter solenoid.

These tests have shown me how a Solenoid reacts to the fields of a permanent magnet.
In order to design the strongest Solenoid possible to help attract the rotorheads past the
sticky spot it must have the same depth as the NdFeb rotor magnet
E.g, if the rotor neo is 5cm thick then its field will reach out approx 5cm at strong flux levels.
This field will enter the solenoid core and get attracted to the field genererated within the core.
If the solenoid was made any longer e.g 10cm, then the 50% of the energy going into the coil
would not affect the neo magnet because the other end is located to far away to contribute any force.
The flux field of a solenoid is always taking the shortest return path, and this is actually inside the core itself.
This is the reason of solenoids having a very weak field at the ends, but the inside of the core is strong.

The next step is to test a Solenoid at 50mm depth to see if my understanding is correct.

[Gregory]

Hi Honk!

Interesting...
I would thought it should work better with a shorter solenoid. Maybe the rotor magnet can more easily saturate the shorter solenoid's core, which is smaller in volume than a thicker one?

By the way, I noticed that you used only one rotor magnet in the earlier test, but now you are using two magnets stacked. This changed the setup and can change the outcome too! So because of this, I think you cannot compare the results.


Another thing... Though it is not for magnetic simulations, I have done some simulation of the spiral motor's principle in Wm2d, and noticed a few things I would like to question in case you have the spiral track completed or tested one before.

If you release the rotor from the starting point just after the solenoid, where will it stop? (without activating the coil)

Does it stop at the last magnet before the coil, or does it stop sooner?
And if you start the rotor from 90 degrees to the coil or even closer, does it stop in the same position?

I think these are important things to check it out.

[Honk]

By the way, I noticed that you used only one rotor magnet in the earlier test, but now you are using two magnets stacked.

No I didn't use just one magnet in the first set of tests. Please see quoted text from my earlier message
"1pcs of N45 40x18x20mm representing the larger rotor magnet"

The picture I posted was showing just one rotor magnet, but I did not use this setup in the solenoid tests.
I switched to 20mm thickness (2 magnets on top) before testing any of the various combinations.

If you release the rotor from the starting point just after the solenoid, where will it stop? (without activating the coil)

I don't know. I have no complete spiral of stator magnets. But I don't believe it will stand still simply because the torque
from the other rotor magnets well inside the stator spiral will thrust forward with great power.

Does it stop at the last magnet before the coil, or does it stop sooner?

Without speed it will stop a little bit, perhaps 1 or 2cm, before the Solenoid.
But at speed it cannot stop right on the spot. It will travel well past the last stator magnet but it will travel a lot easier
when being helped by the Solenoid. My wodden test rig show a great difference in how far the rotor magnet travels.

[Honk]

I just bought a gaussmeter at eBay. It's capable of measuring up to 3 teslas, both AC and DC.
Now I can measure the face flux on the solenoids and magnets very precisely.

[Gregory]

No I didn't use just one magnet in the first set of tests. Please see quoted text from my earlier message
"1pcs of N45 40x18x20mm representing the larger rotor magnet"

The picture I posted was showing just one rotor magnet, but I did not use this setup in the solenoid tests.
I switched to 20mm thickness (2 magnets on top) before testing any of the various combinations.

Ok, I took back my bad words on that.


I uploaded the simulations in case someone would like to have a look at them.
These simulations cannot be compared to a real world device, only show a rough approximation of the main principle involved.

I found that in these sims, the sticky spot appears not exactly at the end of the spiral, but some degrees before. And because of this, the motor worked the best (per input ratio) when the operation of the electromagnet was asymmetrical both in timing & field strength, so giving a greater pull for more time, and a smaller push for less. This may or may not be true in a real motor, however I found it interesting.

I would be interested to know about the differences regarding these things, when compared to an operating real world model of the motor.

Have a Good work!