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  1. M

    Poles per revolution, Bafang 350W hub?

    Looks like this thread might help. https://endless-sphere.com/forums/viewtopic.php?f=9&t=106233&start=25 I have several of these motors/wheels and would like to obtain and use a control for them. Please share what you learn. Regards, major
  2. M

    Exro Technologies

    Listed in "headlines" sent to me by google. First I've heard about it. Anybody have anything on it? https://seekingalpha.com/article/4392202-exro-technologies-is-disruptor-in-electric-motor-industry Looks like an awfully lot of hoopla over 10 milliseconds of torque. Just an improved method...
  3. M

    Milwaukee battery out of balance

    I've had good luck with Milwaukee. But had a cell fail on Craftsman C3-19.2V Li. I replaced the bad cell, just the one out of five. Used solder. As long as I had it open with tools handy, I installed a JST plug. Even though new cell is a mismatch battery seems to function o.k. I have it plugged...
  4. M

    APL's DIY axial-flux motor

    Hi APL, Without straying too far off-topic, envision a clamp style ammeter. Like this: Image from: https://www.fluke.com/en-us/learn/blog/clamps When both leads pass thru, it reads zero. Because the current vectors cancel. Same with 3-phase. You need to clamp around one leg only to get flux...
  5. M

    APL's DIY axial-flux motor

    The difference from most other axial coil arrangements is they use closed loop coils whereas this guy has essentially "open loop coils". In other words, the 40 armature coils are not each closed loops on themselves. All 40 coils close just once. The big circle, as Lebowski puts it, is like a...
  6. M

    APL's DIY axial-flux motor

    Maybe. I don't think distance matters. However, if that "circle" around the steel carries a balanced 3-phase current, would any eddy currents be induced in the shaft steel? major
  7. M

    Need help : number of pole pairs

    Hi Maciek, "Pole pairs" is not the number of coils in the motor. The # of pole pairs is equal to the # of magnets divided by 2, assuming each magnet has a single pole facing towards the air gap arranged in a N S N S .... sequence around the rotor. Most BLDC motors use a stator having a # of...
  8. M

    Reversing a Trolling Motor

    Hi Peno, The brush shift (many call it 'advance') is advantageous due to armature reaction under load distorting the main field flux distribution asymmetrically. For wound field motors the steel pole faces provide path for armature flux perpendicular or tangentially, whereas with ceramic...
  9. M

    Reversing a Trolling Motor

    Hi, For trolling, the standard design of the 2-pole ceramic PM motor aligns the brushes directly with the center line of the magnetic pole. This puts the armature field in quadrature with the stator field. Magnetic neutral = mechanical neutral. No shift (advance) is used. If direction of...
  10. M

    DC Load test large battery packs. Rheostat?

    Hi, Take a look at my load bank. Rack houses 24 locomotive braking resistors, 1.2kW each. Can easily series parallel reconnect for desired load. Most I've done was 200V, 400A. Gray box on side is 1000A contactor with homebuilt IGBT buck converter. Resistors were surplus buy at $7 each...
  11. M

    APL's DIY axial-flux motor

    Hi APL, Actually laminations are used to minimize Eddy currents, not hysteresis loss. Hysteresis is dependent on metallurgy, not shape. Eddies depend on the path and resistance of the path as well as the path orientation to the changing magnetic flux. Eddy current and hysteresis losses are two...
  12. M

    APL's DIY axial-flux motor

    Hopefully that is a link to a download of paper about the subject motor. Looks interesting. Complex/complicated for ? gains. Regards, major edit: link didn't work so here's a screenshot. Hope that helps.
  13. M

    ME1003 Motor

    Cool (no pun intended). How do you measure winding temperature? You know, most times brushes are set to neutral on PM motors. Without steel pole faces near the armature, the armature field distorts the main field much less. The same thing would be true for a PM generator. But whatever works...
  14. M

    APL's DIY axial-flux motor

    Hi APL, Too bad you're having difficulty. Often one pays close attention to the electromagnetic assembly overlooking basic machine design. I've been studying that cross sectional layout of yours. Can't say as I've ever seen where bearing outer races are not completely covered by the housing...
  15. M

    What is this Boat?

    Looks nice and my guess is it would work with series connected pack. But for reliability, I've used multiple units for many years without a single issue, my money would go to Minn Kota. major
  16. M

    What is this Boat?

    BTW, if bilge pump runs off 12V, 2 of the 6V batteries, you'll have uneven discharge across the 4 pack. Then issues using a 24V charger. I'd consider getting a Minn Kota 2 by 12V marine charger. It'll at least equalize to 12V. I've never seen a 4 by 6V charger. major
  17. M

    What is this Boat?

    My guess is it is a PM (permanent magnet) motor. Maybe a Honeywell or Pacific Scientific, maybe Peerless, doesn't look like an Ohio Electric. So likely ceramic magnet stator, guessing 2-pole, wound rotor. Brushes and commutator prone to overheat on overload or long runs on hot days. 2-speed...
  18. M

    APL's DIY axial-flux motor

    APL, Saturation starts limiting at higher flux density, in units of Tesla, which is equivalent to Webers per square meter. So it is the cross sectional area normal to the flux path. A longer tooth means increased magnetic path length which is counterproductive except perhaps providing room for...
  19. M

    APL's DIY axial-flux motor

    It's really the CSA, cross sectional area, which is important to keep the flux density below saturation of the core material. If you're under the saturation level by sufficient margin, the center would be logical place lose material as to keep magnetic circuit paths shorter. But then why not...
  20. M

    APL's DIY axial-flux motor

    The two coil sides cancel. Need area between the conductors carrying current in opposite directions. major {edit} The method shown nets zero current per slot.
  21. M

    Deal on motors/wheels

    I got my order last week. One of the motor leads was cut off so near the axle (like 1/4") it will be impossible to splice. So I popped it open. It's a gear drive so it slipped out of the ring gear. Photo attached.
  22. M

    Deal on motors/wheels

    Thanks. Regards, major
  23. M

    Deal on motors/wheels

    Hi all, A box with 2 wheel-motors was delivered today per my order. Brake calipers and nuts/bolts included. All appears in good condition although obviously used somewhat. Does anybody have a link to the motor spec sheet or better yet, a manual? Would be appreciated. Thanks. major
  24. M

    Deal on motors/wheels

    I received a FedEx tracking number today. Says June 9th. I did send inquiry email yesterday. Fingers crossed. major
  25. M

    APL's DIY axial-flux motor

    Two layers of five is better than single layer of ten turns needing longer core. Proximity of turn to steel core is insignificant magnetically, according to Ampere's Law. Folks have a hard time believing that. Regards, major
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