ZFM Advanced Explorations Part II

[Yaro1776]

6 Pole Phase 2

The machine shop came through with the motor parts today. The parts completed were the Timing rotor and the 6 Pole Neo rotor. Tried a dry assembly of the Neo magnet components along with a steel rod through the center of motor rotor as a magnetic assist. All was good until the placement of the last Neo, then the rotor assembly flew apart damaging two of the Neo's and ending up with two groups of high strength Neo's clustered together. Put this on the Not to Do List, for sure. Separating this mess was tedious.



For attaching the Neo's to the Aluminum rotor a Loctite AA 332 adhesive will be used. This works well, the Neo skin fails before the adhesive. Game plan is to assemble the rotor step by step and use my Weber grill to cure the rotor adhesive at 200F, fact of life when the outside ambient is less than 20F. Indoors the odor from this adhesive can be toxic, never mind the smell.

You will note that the Timing rotor has three sets of holes 120 degrees apart for the 1/4"D mini Neo's. In combination with Reed switches spaced 180 degrees apart, the BP switch board will fire every 60 degrees. Of course the appropriate timing Neo's selection must be in place for this to happen. Another obstacle!

Remains to be seen how all this works out - just an experiment with displaced air core coil poles.

Ho! Ho! Ho!

[dennis foyil]

Yaro, Sincerely, consider bolting those in place along with the epoxy. The neos that is. regards, dennis

[Aaron Murakami]

Yaro, Sincerely, consider bolting those in place along with the epoxy. The neos that is. regards, dennis

Strapping tape works well - both Peter and John used that on top of gluing the magnets.

[Yaro1776]

Yaro, Sincerely, consider bolting those in place along with the epoxy. The neos that is. regards, dennis

Thanks for the concern Dennis and Aaron.

The dry Neo assembly was done to check the fits and forces involved on the rotor prior to applying the adhesive. The rotor was not in the motor and this was part of figuring out the proper Neo mounting sequence. The adhesive will lock everything in place with the strapping tape as a backup - standard procedure in these parts for operation between 6,000-10,000 RPM.

[Yaro1776]

6 Pole First Spin

Another day in the continuing adventure of the 6 Pole ZFM started with mounting two opposing N-S Neo's on the rotor. Rotor was then installed to check the overall pole displacement for each coil. The Neo's are 2"Lx1/2"Wx1/2"T. A certain amount of anticipation here.

Well, as it turns out the coil pole displacement of 60 degrees was not achieved, only 55 degrees - Bummer! It appears that the longer Neo's, with the 1/2" width, behave a bit differently on the 45 degree coil than the 1"x1"x5/8" Neo's. Certainly, there are other influences that modify the coil pole positions.

No matter - time for the spin test; the motor was wired up and then powered up at a conservative 12v for the first trial. No problem starting up and rotating at a couple of thousand RPM. Shutdown at this point to assess the successes and failures before going forward.

Another, more thorough calibration, will be completed within a week and the coil positioning tweaked a bit more based on the calibration data. The intention here is to test this present configuration to establish some initial performance baselines. The coils will be rewound at a later date to adjust for the 5 degrees, however another 6 pole rotor with 2"L Neo's will be tried prior to this modification.

More pics and a video in the next posts.

[Dave Wing]

Thanks for the concern Dennis and Aaron.

The dry Neo assembly was done to check the fits and forces involved on the rotor prior to applying the adhesive. The rotor was not in the motor and this was part of figuring out the proper Neo mounting sequence. The adhesive will lock everything in place with the strapping tape as a backup - standard procedure in these parts for operation between 6,000-10,000 RPM.

When it comes to strapping tape this stuff is the best I have found and it can be picked up most anywhere. I have never thrown a magnet when using this tape. http://www.bunkerincorp.com/hurricane.htm

I hear some of you guys have issues with throwing magnets at high rpm, this tape will prevent that unsafe event from happening period. Run as much tape as your air gap will allow, make sure each wrap around the rotor is applied under tension so each consecutive wrap will apply more compression, holding your magnets tighter to the rotor. You want close to an 1/16th of an inch for wrap thickness when the rotor is taped. Do this and you can run any rpm you want on smaller machines like the ones on this thread.

Dave Wing

[Yaro1776]

Dave,

Thanks for the lead on the Uber strapping tape. Checked out the url and it appears worthy of a trial. As the rotors increase in diameter and the Neo's become bigger every little bit of extra retention helps. The Neo's skin usually fails first!

[Yaro1776]

First Run 6 Pole YZFM w/ Two Opposing N-S Neo's

After all the trials and speed bumps the 6 Pole ZFM was assembled this past weekend. It took a number of hours to properly align everything and to get the timing as close as the Reed switch method allows. Not perfect as yet...

The motor accelerates well for a 2 out of 6 Neo config and the low RPM torque is fairly robust. The bare two finger toque test manages to heat up the finger tips rapidly. All of this is just the beginning of another most excellent adventure.

So for the video the basic operating parameters are 30.24 volts at 1.15 Amps with 3980 RPM.

The motor is still being broken in and needs a bit of run time. The expectation is that it will work easily up to 48 volts in these initial trials. The timing/coil arc does need a bit of work to fully develop the potential power capabilities, however this will be for a later date.

Next step is to do a number of trials with the other twin Neo 1"X1"x3/4" rotor. After removing the first rotor the additional 4 Neo's (2"x1/2"x1/2") will be glued to it and cured. Need to observe how the bigger (1"x1"x3/4") Neo's operate with the 60 degree coil pole displacement. Right now the coil pole arc is at 52 degrees with the smaller Neo's.

Thanks for your attention.

[Joster]

Most excellent work Yaro as always. That is the nicest Bedini Cole Switch PCB I have ever seen. Looking forward to more updates!

[Yaro1776]

Further Experimental Data for Two Neo 6 Pole

Well, I could not leave this 2x1/2x1/2 config alone and decided to torque test it just to say it was done.

The last torque test for this config demonstrated that for a 2 pole it is pretty gutsy. It is capable of starting under load from a rest position with 550 grams of weight and accelerating to 2410 RPM at 37.01v at 1.69A. It was not pushed! Plenty of low end torque and it gets up to speed rapidly with this load. There still remains the sense that the machine is fighting itself due to the extended firing duration of over 50 degrees. There is a ways to go for an improvement in performance.

Ancient history for now that the rotor has been updated to to the full complement of 6 Neo's with the new timing duration of about 42 degrees, though a bit under the target powered duration. Nevertheless, ready to be installed on 12/20/19 after the obligatory fiberglass wrapping tape procedure. Pic of the new fashion Rotor:



The assembly procedure used here was to clamp the rotor in a vice and use a pair of wood clamps to handle the Neo's for assembly - a much safer procedure than using the fingers. Used an AA 326 Adhesive (Loctite) with an SF 7649 Primer yielding a rapid cure to full strength. Low odor and readily available versus the AA 332 adhesive, but with about 75% of total strength. Let's see how this works out as the experiment progresses.

Pic of rotor with Mag Film:



In closing, the other bigger rotor performed up to expectation, but more definitive data may be posted after a new rotor design has been machined and tested. That may be a ways out based on the shop's work load and available design time.

Season's Greetings and Happy Holidays from the back hills of Vermont.

[Yaro1776]

Taming the 6 Pole Beast

Happy Christmas to all,

A quick up date on progress for the 6 Pole ZFM. Most of the past week has been spent working with the ZFM timing and getting the machine to perform such that it be ready for prime time.

The current timing method with the reed switches does work well enough to make this motor perform and it does demonstrate that the 6 Pole is a different Beast of the ZFM family. It is a low speed motor in comparison to the 4 Pole and with very good torque over a wide range. The torque is such that the existing Torque device is not adequate to measure the maximum torque at higher than the 1000gr levels.

The timing is a bit touchy/sensitive, but can be worked to provide good and consistent data. It has been operated up to 6000+ RPM and 48volt, and it can easily be pushed up to 60 volts to expand the torque curve.

Best efficiency to date with the current config has been 45%, and perhaps the 50% barrier may be achieved over the next several days - wait and see on this.

Ready to present a video of the 6 Pole beasty shortly. Ho! Ho! Ho!

[Aaron Murakami]

Merry Christmas Yaro, thanks for sharing - 45%! That's over double the original 20% from the other variations so definitely moving in the right direction!

[Yaro1776]

6 Pole ZFM with 6 Neo's Video Run

Hello to All,

Finally put together the first public video of the 6 pole rotor with all the Neo's in place. This motor does run strong and for the video a load of 770 grams was used throughout the experiment as a constant load factor for voltages from 24v to 60v in 12v increments.

Inadvertently a few data points in the video were omitted; included are the nominal voltages for the experiment:

2032 RPM 24.0v 0.22A No Load
1550 RPM 24.0v 0.52A w/ Load
2360 RPM 36.0v 0.65A w/ Load
3064 RPM 48.0v 0.73A w/ Load
3840 RPM 60.0v 0.78A w/ Load
4690 RPM 60.0v 0.43A No Load

It appears that this particular ZFM configuration has been tuned relatively close to its limits, but early days as yet. The overall efficiency comes in around 45% with several data points over 50%. This does show the inherent potential of the 6 Pole ZFM as a direct drive motor over a wide range of voltages.

The intention here is to add the spike recovery circuit to the configuration in the near future once all the necessary LAB's are collected and charged.

There is more, but the video process required numerous takes due to technical gremlins. More than enough for now!

Thank you for your attention and Happy New Year.

[Yaro1776]

Maximum Torque at 24v

Hello to all,

Things were slowed down a bit due to a bearing failure, but that has been corrected and deemed good. The subsequent experiments have been centered around a beefed up torque testing apparatus and this has allowed pushing the limit up to 1450 grams - nearly double the previous maximum.

The acid test here was to cold start the 6 pole ZFM at 24v nominal in a loaded condition (1450 gr) and this was easily accomplished yielding a speed of 1060 RPM at 1.17A. The no load speed at this voltage was 2304 RPM at 0.31A.

This clearly demonstrates the low speed torque capability of the 6 pole configuration. This load value is perhaps the maximum for this voltage's torque curve - overall efficiency dropped off from a nominal 45% to under 35%. The other voltages (36, 48, 60) were not impacted and continued to operate in the 45% efficiency mode under this load.

The last item on the agenda for this particular rotor config is to plug in the BEMF circuit and see how the collected wasted energy impacts the performance of this machine. The 6 pole configuration has significantly more BEMF than the 4 pole motor - this can be observed at the end of the last video in the prior post. More on this in the next post.

The 4 pole design is still very worthwhile for higher speed operation and it does have very good torque. One does have to bear in mind that the fruits of the 4 pole experimentation have been applied to this 6 pole config. A new build of the 4 pole, based on this prior experience, should also yield results that are comparable.

The new forum format works well for me - thanks Aaron!

Over and out for now!
Yaro

[Yaro1776]

6 Pole ZFM with BEMF Circuit

The last experiment in this series was to operate the 6 pole configuration with the Cole BEMF circuit in conjunction 24v LAB for power. The diagram for this circuit is below:
The BEMF circuit was attached to the coil power input and the BEMF circuit output was wired directly to the incoming 24v power leads. The ZFM was powered up and operated at the 24v provided by the LAB's with the following loads: 0gr, 775gr and 1460gr.

This data was then plugged into the spreadsheet and the values compared to a prior run without the BEMF circuit:
With BEMF Circuit (LAB)
2384 RPM 25.14v at 0.29A ; 0gr Load
1711 RPM 25.11v at 0.75A; 775gr Load 46% Eff.
1201 RPM 24.99v at 1.14A; 1460gr Load 40% Eff

Without BEMF Circuit (Power Supply)
2304 RPM 24.21v at 0.31A; 0gr Load
1535 RPM 24.26v at 0.74A; 775gr Load 43%Eff
1060 RPM 24.45v at 1.17A; 1460gr Load 35%Eff

The above does demonstrate that the circuit is a positive addition to the 6 Pole due to the high level of induced voltage. Furthermore this can be viewed graphically in the below pics. First pic demonstrates the smoothing action by the circuit. The second depicts the BEMF wave without smoothing on power down - a 60v pic was used for the sake of wave clarity. There is a third pic that depicts 60v operation without the recovery circuit.

Yaro