Announcement

Collapse
No announcement yet.

The bistander thread

Collapse
X
 
  • Filter
  • Time
  • Show
Clear All
new posts

  • Quantum_well
    replied
    I just feel that Bro' either doesn't understand or won't accept the value of torque/rpm analysis. With a proper set-up the drive motor size (within reason) has no bearing on the power it is outputting. The example I gave was doable by most who post on here and it avoids a $2000 dollar investment in the kit needed to use a rotary sensor.
    Having said that I really enjoyed the YouTube links Bro' put on. There's a huge amount of skilled work in reconditioning these big motors. I had always wondered how all those coils were put into a motor.I had a go at rewinding a small motor and I managed to get it looking somewhat like although it never ran satisfactorily.

    Leave a comment:


  • BroMikey
    replied
    All these motor video's are not going to make your thread look intelligent but if you insist. Get a good look.

    Leave a comment:


  • BroMikey
    replied
    HOW ABOUT THIS MOTOR FOR YOUR 8 OZ ROTOR?

    https://www.youtube.com/watch?v=itDcOSK_5Rg

    Leave a comment:


  • bistander
    replied
    Originally posted by Quantum_well View Post
    This YouTube guy has the right idea. There's no way most of you lot are getting accurate results with drive motor current and it's all too easy to fool yourselves.

    https://youtu.be/1Pd0lUKWe7o

    I wonder if the video will pass bistander scrutiny?.
    Thanks.
    I like this guy. He does a nice job. He flies past the dynamometer trunion bearing mounting pretty fast. But I watched his other vid and he covers it in detail. I don't see where he balances (static calibration) the torque arm system, but overall he's got a good system.

    Another thing comes to mind. He treats the dynamometer as a motor with his power supply. Realize it is actually a generator so needs an electrical load to apply torque opposing rotation and dissipate power. I've used shunt wound DC motors with an adjustable power supply on the field and big low ohm resistor across the armature. A PMDC motor will work for the dynamometer needing no power supply but using a variable resistance across the armature.

    His other vid. * Nice vids from this guy. I approve.
    bi

    *Hmmm. Edit. Just checked video link. Looks to be same as supplied by q_w. I must have somehow skipped part the first time I viewed it. Oh well.
    Last edited by bistander; 05-30-2021, 03:05 PM.

    Leave a comment:


  • Quantum_well
    replied
    This YouTube guy has the right idea. There's no way most of you lot are getting accurate results with drive motor current and it's all too easy to fool yourselves.

    https://youtu.be/1Pd0lUKWe7o

    I wonder if the video will pass bistander scrutiny?.

    Leave a comment:


  • BroMikey
    replied
    Originally posted by bistander View Post


    Notice the precision popsicle stick shims.

    Screenshot_20210529-001620-283.png

    Think his core is dead nuts to +/- .001"?

    (Images previously posted on this forum by BM.)

    bi
    Here is what needs to be understood about this giant motor using a plastic rotor with small weak magnets and a coil the size of a spool of thread. The motor will consume 65% of it's FLA with no rotor. With the rotor that is so small the amps will not change. With a coil and rotor the 65% mark would still not be reached. A motor like this is a poor choice for accurate testing UNLESS a VFD is used to dial past this problem. It is possible. A motor like the one in the picture might have a FLA (full load amps) of 10 amps and so 65% would be 6.5amps regardless.

    What we need is a small record player motor that teeters on the edge of barely turning the rotor BEFORE cogging coils are added one after another. Then you can see slight increases where on a motor this large you might need a 30" rotor with 10-20 one pound magnets to reach this limit. 6.5a X 120v = 780 watts. I run a rotor this size on 10 watts.

    And that coil holder bolt will giggle like a Palm tree.


    Last edited by BroMikey; 05-29-2021, 10:15 PM.

    Leave a comment:


  • bistander
    replied


    Notice the precision popsicle stick shims.

    Screenshot_20210529-001620-283.png

    Think his core is dead nuts to +/- .001"?

    (Images previously posted on this forum by BM.)

    bi

    Leave a comment:


  • BroMikey
    replied
    If anybody is interested here is the small school boy machine running at 1750 rpm's showing a 294 hertz or 294 divide by 10 magnet pole X 60 sec to get RPM of of hertz = 1750. Very slow where the big machine uses a 10" rotor with 20 magnet poles and runs at over 4000 rpm.

    Last edited by BroMikey; 05-29-2021, 09:42 PM.

    Leave a comment:


  • BroMikey
    replied
    Originally posted by bistander View Post
    Screenshot_20210527-234008.png
    Looks precision?

    Please go back to your thread and post the results you've obtained with your machine.
    bi
    I see you are getting confused. There are 2 machines here. One is the big machine and the other is the School Boy sized machine. The smaller rotor you keep showing is the 6" and was designed for around the slow speed of 1500 rpm's, the other one is not shown and is a bit more precise tho it too has the adjustable stations where magnets are adjustable. Everything is also balanced.

    http://flyer.thenetteam.net/3battery...trandcoil4.jpg

    Last edited by BroMikey; 05-29-2021, 09:47 PM.

    Leave a comment:


  • bistander
    replied
    Screenshot_20210527-234008.png
    Looks precision?

    Please go back to your thread and post the results you've obtained with your machine.
    bi

    Leave a comment:


  • BroMikey
    replied
    Originally posted by bistander View Post
    This guy complaining about lack of precision and methods in my test rig posts up an example of his work here:



    Take a look and tell me where he gets off ranting at me.
    bi
    Thanks Bye Yes this video has a great alignment on the rotor but the guard is a bit of a chop job. The rotor is also a bit of a back yard chop job as stated. Here is what you missed. The rotor magnet holders on the rotor ARE adjustable. So what you didn't see was me setting up the 20 magnet holders that all can be locked into a perfect location. Here is what I did. I set up the 20 magnets dead nutz over a single core with an opposition core in the back. Each handmade and hand positioned magnet was aligned perfectly over the core both X and Y axis. The Z axis is also adjustable at the same time which the Z axis represents the distance the magnet is away from the core. All adjustable. You can set up one without a machine shop this way.

    Thanks for asking. See other video's on the 20 magnet rotor setup, not so easy as I make it sound. If alignment is off you may reset all of the locations which I did do a few times till I liked it. Most people just shell out a few grand to the machine shop. Machine shop fees are $75 per hour. Now if I was made out of money like another guy I know.......


    The 4th aspect of rotor design is balancing also explained. which is a completely different field of study called mechanical design, not to be short changed. All fields of study hold merit.

    Rotor magnet adjustments explained.

    Last edited by BroMikey; 05-28-2021, 05:27 AM.

    Leave a comment:


  • bistander
    replied
    This guy complaining about lack of precision and methods in my test rig posts up an example of his work here:

    Originally posted by BroMikey View Post
    In this test I told you I would come back and make more test
    ...
    This is an infinity generator.



    Take a look and tell me where he gets off ranting at me.
    bi

    Leave a comment:


  • BroMikey
    replied
    Originally posted by bistander View Post
    Using four magnets, all N facing, on the rotor, at 4800 RPM constant

    a magnetic circuit using PMs and wide air gaps will fringe and compensate for a great deal of misalignment. It is not like magnetic flux needs straight line pathways.

    bi
    DRAG, you can not get even close. give it up and make machined cuts. All this talking yourself into an 'it;s okay whatever' is a funny joke on you.

    Leave a comment:


  • bistander
    replied
    Using four magnets, all N facing, on the rotor, at 4800 RPM constant, adding 6 cores, one at a time, showed an increase in prime mover power of 2 watts each. 13 watts was required with no cores near the rotor and 7 watts at zero RPM (PWM energized set at zero duty cycle).

    While a single strand conventional wound coil may show some loss when unconnected, I doubt it can be detected at these frequencies with commonly available instruments.

    ​​​​​The test fixture can mitigate cogging using an opposition/neutralization magnet at 180, using 4 or 12 magnets on the rotor, indicating the desired response. Neither the rotor nor stator core or magnet are precision located but are adequately positioned to demonstrate the desired effects. Again, the flux in a magnetic circuit using PMs and wide air gaps will fringe and compensate for a great deal of misalignment. It is not like magnetic flux needs straight line pathways.

    bi
    Last edited by bistander; 05-27-2021, 09:29 PM. Reason: Typo

    Leave a comment:


  • BroMikey
    replied
    Originally posted by pmgriphone View Post

    Exactly. A coil has capacitance and inductance at the same time. So even if it is not connected externally, there is still an internal circuit where current flows and this current will impact the prime mover, especially if it is a resonant circuit where lots of energy piles up (thus high voltage on the capacitance of the coil (dielectric energy) and thus high current when this converts from dielectric field 0.5*C*V^2 into magnetic field 0.5*L*I^2)
    Yes all generators have coils and all coils pose a slight drag of induced static fields. Now having said this twice I will give you my example. My latest school boy machine used at school ran at right around 500ma to keep the rotor moving without a core and without a coil. Then a coil and core was connected. With a core and a coil the amp draw of the prime mower climbed up 50 ma at speed. I this case we were running speeds of 1200-1500 rpm. Keep in mind that no load was connected to the coil. Just a slight induced field into the wire and the cogging of the core, no opposition magnets either.

    Bye can not show the single opposition test because his rotor will not respond the same at 180 degrees. or 90 degrees. He has 4 rotor magnets randomly placed.

    Leave a comment:

Working...
X