Search found 80 matches

by KD5ZXG
May 17 2019 10:52pm
Forum: Motor Technology
Topic: 555 timer
Replies: 6
Views: 216

Re: 555 timer

http://www.ti.com/lit/ds/symlink/lmc555.pdf

Specs improved over the original version. 3MHz, 50mA.
I'm not reading in depth so maybe missing something...
by KD5ZXG
May 02 2019 3:30am
Forum: Battery Technology
Topic: I "finished" my first 10s10p battery using vruzend 1.5 kit
Replies: 2
Views: 220

Re: I "finished" my first 10s10p battery using vruzend 1.5 kit

Might make better balance to blend mismatched cells to matched sums for each parallel group? You say matched series strings, but I can't figure how that alone guarantees parallel balance. I have no prior pack building experience, could be misunderstanding how that works. Got a 36V mid motor, and eno...
by KD5ZXG
Apr 25 2019 3:25pm
Forum: Motor Technology
Topic: APL's DIY axial-flux motor
Replies: 340
Views: 14504

Re: APL's DIY axial-flux motor

Keep the plates and save your work. Just cut slots and shim with epoxy or other insulator. Not at the place where you have already tapped a set screw. Jigsaw an angle from one side (perhaps the clockwise side) of each stator to the outer edge. So you will still have one solid plate, but no shorted t...
by KD5ZXG
Mar 28 2019 7:19pm
Forum: Motor Technology
Topic: Induction Motors ?
Replies: 3
Views: 201

Re: Induction Motors ?

Once was a thing called "repulsion motor" that ran as a squirrel cage induction motor. But had liftable brushes for extra low speed torque and starting. I don't understand how it worked. Was good enough for trains...
by KD5ZXG
Mar 15 2019 11:25pm
Forum: Motor Technology
Topic: APL's DIY axial-flux motor
Replies: 340
Views: 14504

Re: APL's DIY axial-flux motor

Don't make the guts too inacessible. Huge stationary shorted turns remain about each end of the stator coils. Those shorts will eventually need to be jigsawed open before it works at reasonable RPM. You could still step with it at very low rate to measure torque. Near DC, shorted turns of the plates...
by KD5ZXG
Mar 04 2019 3:08am
Forum: Motor Technology
Topic: Why never see metal cast around wound stators?
Replies: 67
Views: 2332

Re: Why never see metal cast around wound stators?

If an ac current were being fed through the coils at a fast enough frequency to produce eddy currents the iron teeth would be heating up especially as it’s feromagnetic and would be heating through hysteresis as well as Eddys. But they don’t heat through these and the frequency is not fast enough. ...
by KD5ZXG
Feb 28 2019 10:59pm
Forum: Motor Technology
Topic: HyMag tech boosts magnetic flux density of permanent magnets by 10-30%
Replies: 25
Views: 1499

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

Either type of magnet weighs more than iron. SmCo Gives a temperature advantage over NdFeB in return for brittleness and slightly weaker field. Yes, we can get rid of backing iron. Replace with cobalt, or add more heavy magnets to make an array that needs no backing, but not always helpful to do so....
by KD5ZXG
Feb 28 2019 10:17pm
Forum: Motor Technology
Topic: HyMag tech boosts magnetic flux density of permanent magnets by 10-30%
Replies: 25
Views: 1499

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

Monkey see monkey do. Lams are always safe. Properly placed dead shorts can work significantly better. Not impressed. AC induction motors work entirely on eddies and nothing else. What would be the performance of this motor without them? 793px-Rotterdam_Ahoy_Europort_2011_(14).JPG What I speak of is...
by KD5ZXG
Feb 27 2019 4:26pm
Forum: Motor Technology
Topic: HyMag tech boosts magnetic flux density of permanent magnets by 10-30%
Replies: 25
Views: 1499

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

In fact there will be eddy currents induced within magnets and back iron, because the rotating magnetic field from the stator is spinning quicker as the rotor itself (ERPM vs. RPM). Stator field leads the rotor field by some angle of course, but is not spinning quicker. Maybe you are thinking AC in...
by KD5ZXG
Feb 27 2019 5:34am
Forum: Motor Technology
Topic: HyMag tech boosts magnetic flux density of permanent magnets by 10-30%
Replies: 25
Views: 1499

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

So, my suggestion of roller bearings in place of Maxon's brushes might not have been completely daft. Not sure how much current Bosch intends to push through these? Perhaps this illustration was just about bleeding some unwanted voltage that accumulates.
bosch.jpg
by KD5ZXG
Feb 26 2019 6:08pm
Forum: Motor Technology
Topic: HyMag tech boosts magnetic flux density of permanent magnets by 10-30%
Replies: 25
Views: 1499

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

Halbach is no magical replacement for backing iron. Nd2Fe14B is 72.3% Iron by weight. Twice as many magnets are then needed to form the array. So much for getting rid of iron... "Iron losses" aren't a problem in permanent magnets or their backing. Because a constant flux doesn't generate eddies. If ...
by KD5ZXG
Feb 25 2019 7:48am
Forum: Motor Technology
Topic: APL's DIY axial-flux motor
Replies: 340
Views: 14504

Re: APL's DIY axial-flux motor

I don't understand a single word. What do you mean with "shorted turn"? Exactly which part of "shorted turn" did you not understand? Currents induced in the plates will oppose those of the coils. Flux cancelled by an equal and opposite magnetomotive force. If the surrounding circuit is not opened, ...
by KD5ZXG
Feb 24 2019 9:45pm
Forum: Motor Technology
Topic: APL's DIY axial-flux motor
Replies: 340
Views: 14504

Re: APL's DIY axial-flux motor

Uh, wait. Am I just now understanding that your stator intends to alternate and present the rotating fields? I should have realized earlier... Eddies are the least of your problem. You need to do something about slotting those plates so they won't represent a shorted transformer secondary winding. I...
by KD5ZXG
Feb 20 2019 9:21pm
Forum: Motor Technology
Topic: Why never see metal cast around wound stators?
Replies: 67
Views: 2332

Re: Why never see metal cast around wound stators?

Eddy? Huge shorted transformer secondary more like it.
Not recommended for stator with an alternating flux.

Shorting ring (or bury in cast metal) might help a DC field
coil or permanent magnet rotor that doesn't change flux.
For fixed flux application, idea may not be entirely daft.
by KD5ZXG
Feb 14 2019 11:20pm
Forum: Motor Technology
Topic: HyMag tech boosts magnetic flux density of permanent magnets by 10-30%
Replies: 25
Views: 1499

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: 25
Views: 1499

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: 340
Views: 14504

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: 340
Views: 14504

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: 340
Views: 14504

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: 340
Views: 14504

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: 340
Views: 14504

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: 340
Views: 14504

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: 340
Views: 14504

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: 340
Views: 14504

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: 340
Views: 14504

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...