Search found 66 matches

by KD5ZXG
Feb 14 2019 11:20pm
Forum: Motor Technology
Topic: HyMag tech boosts magnetic flux density of permanent magnets by 10-30%
Replies: 5
Views: 306

Re: HyMag tech boosts magnetic flux density of permanent magnets by 10-30%

https://www.electronicsweekly.com/news/research-news/rare-earth-free-magnet-made-from-cheap-materials-2016-05/ Its nothing new that various thin films can be made twice as powerful as bulk Neodymium Iron Boron. But the trouble is they are just thin films. Many rely upon strain, which cannot happen e...
by KD5ZXG
Feb 14 2019 7:47pm
Forum: Motor Technology
Topic: HyMag tech boosts magnetic flux density of permanent magnets by 10-30%
Replies: 5
Views: 306

Re: HyMag tech boosts magnetic flux density of permanent magnets by 10-30%

https://www.anl.gov/article/stronger-lighter-greener

Possible link to the original article? OP link roboplagiarized to the point of nonsense. I mean, "Neodymium" somehow changed to "Niobium"? Same things only completely different, nobody cares if we change a few facts...
by KD5ZXG
Feb 13 2019 12:54am
Forum: Motor Technology
Topic: APL's DIY axial-flux motor
Replies: 181
Views: 3831

Re: APL's DIY axial-flux motor

Dip end of Litz bundle with lots of flux in a pool of molten tin. Enamel will usually burn itself off, unless its not real enamel. Pure tin melts about 48C hotter than regular lead/tin solder. May be part of the magic when burning off enamel? Our pool is pumped more like a fountain or volcano. Can r...
by KD5ZXG
Feb 12 2019 7:47pm
Forum: Motor Technology
Topic: APL's DIY axial-flux motor
Replies: 181
Views: 3831

Re: APL's DIY axial-flux motor

You post gold filled square copper wire and complain Litz costs too much?
by KD5ZXG
Feb 12 2019 3:42pm
Forum: Motor Technology
Topic: APL's DIY axial-flux motor
Replies: 181
Views: 3831

Re: APL's DIY axial-flux motor

Rectangular Compacted Litz.

Skin effect may not matter for reasonable motor frequencies.
But proximity effect still matters, as does breaking up eddies.
https://en.wikipedia.org/wiki/Proximity ... magnetism)
by KD5ZXG
Feb 11 2019 5:56pm
Forum: Motor Technology
Topic: APL's DIY axial-flux motor
Replies: 181
Views: 3831

Re: APL's DIY axial-flux motor

Neodymium magnets are 14 parts iron to three parts other stuff. 2 parts neodymium. 1 part boron. So much for eliminating iron... Samarium Cobalt: 5 parts Cobalt to one part Samarium. Extremely brittle, but won't corrode, and takes heat better. Definitely not saying Cobalt makes a better motor than i...
by KD5ZXG
Feb 07 2019 3:55am
Forum: Motor Technology
Topic: APL's DIY axial-flux motor
Replies: 181
Views: 3831

Re: APL's DIY axial-flux motor

For no backing iron entertainment purposes only:
try searching: "Halbach Array"
by KD5ZXG
Jan 30 2019 12:43am
Forum: Motor Technology
Topic: APL's DIY axial-flux motor
Replies: 181
Views: 3831

Re: APL's DIY axial-flux motor

https://en.wikipedia.org/wiki/Magnetomotive_force Word I was thinking of earlier but couldn't recall. Will need unreasonable large current, lots of turns of tiny wire to push big flux through empty space. Only because empty space is reluctant to pass flux that you can do work against it, and store e...
by KD5ZXG
Jan 29 2019 11:48pm
Forum: Motor Technology
Topic: APL's DIY axial-flux motor
Replies: 181
Views: 3831

Re: APL's DIY axial-flux motor

Maybe I don't totally get Faraday, or Topology, but a field might orient itself through the middle of the coil no matter how you bent it. What you going to do if this coil's field is perpendicular to your permanent field? Am I imagining the picture from too far to see some local effect you are tryin...
by KD5ZXG
Jan 20 2019 10:41pm
Forum: Motor Technology
Topic: APL's DIY axial-flux motor
Replies: 181
Views: 3831

Re: APL's DIY axial-flux motor

Failure to address reluctance of flux return path around outside of coil. Not a big deal, just embed in a pipe of laminated iron or bailing wire. Taking care not to complete an electrical circuit, only magnetic. Failure to address reluctance of gap for coil to pass through. Failure to address eddies...
by KD5ZXG
Jan 09 2019 1:24am
Forum: Motor Technology
Topic: APL's DIY axial-flux motor
Replies: 181
Views: 3831

Re: APL's DIY axial-flux motor

Copy/Paste propaganda from JB's website. Q:How much heat can J-B Weld withstand? A:Original J-B Weld can withstand a constant temperature of 500º F. The maximum temperature threshold is approximately 600º F for a short term (10 minutes). Refer to individual product packages for more temperature info...
by KD5ZXG
Jan 04 2019 12:33am
Forum: Motor Technology
Topic: APL's DIY axial-flux motor
Replies: 181
Views: 3831

Re: APL's DIY axial-flux motor

I havn't yet read everything I should between page one and last of this thread, trying to squeeze this visit into a very short break. Back in the beginning, you were mixing up some epoxy and powder that you first called ferrite then iron. So I don't know exactly what you mixed... Now when I do this,...
by KD5ZXG
Dec 18 2018 6:25am
Forum: E-Bike Non-hub Motor Drives
Topic: New "TSDZ2 Torque Sensor Central Motor"
Replies: 4430
Views: 312569

Re: New "TSDZ2 Torque Sensor Central Motor"

very embarassing....i have broken half of the surrounding magnet....it is part of the 850C display. So my question: can the device still be working or is it impossible? if anyone knows enough about this kind of coil...it should be just the shield..so maybe I am in luck.. You have reduced the induct...
by KD5ZXG
Nov 14 2018 9:30pm
Forum: Motor Technology
Topic: Ferrite as a stator material?
Replies: 17
Views: 1436

Re: Ferrite as a stator material?

Then let me ask a few physics question that's been puzzling me. Why does flux in free space mushroom around the easiest path instead of the entirety taking the easiest path? I'm assuming its like different resistors in parallel, but I'm not sure. Then you got quanta, which means lines instead of a s...
by KD5ZXG
Nov 13 2018 9:39pm
Forum: Motor Technology
Topic: Solid State relays Controller?
Replies: 3
Views: 251

Re: Solid State relays Controller?

Solid state relays are bricks made of mosfets and isolated couplers selected for a different purpose. Why is this better than mosfets and isolated couplers selected for the purpose of driving a motor?
by KD5ZXG
Nov 07 2018 10:26pm
Forum: Motor Technology
Topic: Ferrite as a stator material?
Replies: 17
Views: 1436

Re: Ferrite as a stator material?

I've molded a few composite inductor cores of JBWeld (5% Ferrosilicon "steel" Filler). Can highly recommended for energy storage or flyback choke only, not for motor. Too much reluctance from too much distributed gap. Only conducts flux 3~6x better than air, which might be enough to guide the field ...
by KD5ZXG
Nov 06 2018 4:45pm
Forum: E-Bike Technical
Topic: Lithium battery pack repair help?
Replies: 7
Views: 309

Re: Lithium battery pack repair help?

One of the things a proper working BMS does is drain overcharged cells. Hopefully before they overcharge too much and become hazardous. However, draining generates heat. Too much heat to keep pace with a charger of reasonable speed. Therefore the charge may shut off before completion, and the high c...
by KD5ZXG
Oct 31 2018 12:29am
Forum: E-Bike Non-hub Motor Drives
Topic: New "TSDZ2 Torque Sensor Central Motor"
Replies: 4430
Views: 312569

Re: New "TSDZ2 Torque Sensor Central Motor"

A stack of washer rings as you linked (pic shure looks like BB30 and cassette might be same diameter) could work. You say its been done already, so lets say I trust. OTOH: Looks like Lingbei GP could be the rare exception, not wanting/needing a ring. Some sort of cone shape fits inside BB30 or adapt...
by KD5ZXG
Oct 30 2018 11:50pm
Forum: E-Bike Non-hub Motor Drives
Topic: New "TSDZ2 Torque Sensor Central Motor"
Replies: 4430
Views: 312569

Re: New "TSDZ2 Torque Sensor Central Motor"

This: AmericanMisfit.jpg Correction: Looks like this Bafang may have same problem, wanting same or similar ring. 01,02,HD, none are flat. What made me think they were flat? Better yet, why does Luna (who should definitely know better than I) make adaptors as-if all inside faces were flat??? another ...
by KD5ZXG
Oct 30 2018 11:12pm
Forum: E-Bike Non-hub Motor Drives
Topic: New "TSDZ2 Torque Sensor Central Motor"
Replies: 4430
Views: 312569

Re: New "TSDZ2 Torque Sensor Central Motor"

Luna shape probably works fine for Bafang. For TSDZ2, you need the green highlighted ring chainside, as shown on Bikewow adaptor. Else BB30 surrounding ridge of TSDZ2 is all that touches (red) an American bottom bracket. Taking side clamping force in a bad way. Red is not a problem with this adaptor...
by KD5ZXG
Oct 30 2018 1:31am
Forum: E-Bike Non-hub Motor Drives
Topic: New "TSDZ2 Torque Sensor Central Motor"
Replies: 4430
Views: 312569

Re: New "TSDZ2 Torque Sensor Central Motor"

I "bought" Sturmey hubs and several things I needed from a seller that took the money and never shipped. My remaining budget for 3D is zilch. Hopefully the CSA trade goes better. Buyers regret over a buck worth of chopsticks, when I could have used twigs from the yard.
by KD5ZXG
Oct 30 2018 12:18am
Forum: E-Bike Non-hub Motor Drives
Topic: New "TSDZ2 Torque Sensor Central Motor"
Replies: 4430
Views: 312569

Re: New "TSDZ2 Torque Sensor Central Motor"

Re Rydon, let me take a wild stab in the dark guess. No facts, just speculation: Don't see how you could backpedal without the motor backpeddlin' along with you. I mean, wouldn't that strip a gear trying to spin the motor? Therefore you prolly got 500W of coaster braking assist. More than you may ac...
by KD5ZXG
Oct 24 2018 1:08pm
Forum: E-Bike Non-hub Motor Drives
Topic: New "TSDZ2 Torque Sensor Central Motor"
Replies: 4430
Views: 312569

Re: New "TSDZ2 Torque Sensor Central Motor"

So, finding some new hope after losing a bunch of money on ripoffs. I decided was as good a day as any to bang out my bearing cups and try to fit TSDZ2 on the Electra I had originally intended it for. The hole through the cups was plenty bigger than 30mm, but the motor won't clear the bottom edge un...
by KD5ZXG
Oct 23 2018 1:35am
Forum: Motor Technology
Topic: Switched Reluctance Motors
Replies: 49
Views: 4245

Re: Switched Reluctance - Ideal for DD Hubs?

SRM has to add and remove energy from a rapidly changing inductance. Braindead sinewaves won't produce the smooth result you might expect. There may not be any simple simple fix for silencing audible bumps that are harmonics of any reasonable direct drive cog rate. Now on the other (not direct drive...
by KD5ZXG
Oct 11 2018 5:18pm
Forum: E-Bike Non-hub Motor Drives
Topic: Bafang BBSxx - fault finding and fixes
Replies: 1037
Views: 144722

Re: Bafang BBSxx - fault finding and fixes

The way I test N-CH FETs: 0) Disconnect any other source of power. 1) Disconnect any load that mimics a short (motor windings) 2) Using two volt/ohmeters to measure each other. Set one Ohms the other Volts. 3) Each need to output more than 4V on ohms test to have any chance of working. 4) Abuse one ...