Recent content by major

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

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...

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...

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...

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...

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

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...

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...

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...

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...

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...

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.

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...

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...

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