Eddies and cogging are different.
That’s what I’ve been saying. No cogging. More iron loss
It absolutely is, there was no argument about that. But cogging is not what is causing the motor to slow down in unpowered use. While it feels notchy, it is not the source of the resistance.
Then what is it. Don’t tell me eddies or hysteresis again. They don’t express as high torque at very slow speeds
you store some kinetic energy as potential energy during part of the rotation, and convert potential energy to kinetic in another part… no net loss
Thrn the motor rolls like a regular wheel…but it doesn’t
What do you want the answer to be? Magnets passing over conductive material causes a opposing magnetic field which induces electrical resistance that converts to heat and lost energy.
Listen to this: can have the same magnets pass at same speed over MORE conductive material (slotless motor) and get no cogging.
Slotless motor has more material exposed to magnets
Yes, it will have no cogging, in fact, take a motor and short all the phase wires. no cogging. but shit won’t roll at all.
Cogging happens unrelated to the wire. I know u can short phases. So what.
YES, you’re proving my point. Cogging is unrelated to the drag of the motor. 2 separate problems. Cogging is magnet staggering to stator. Resistance is the magnets moving over conductive shit. You can have one problem without the other.
Think about why a motor stops cogging when all the phase wires are shorted.
So iron losses are the dominant loss at slowest speeds, then virtually disappear and reemerge following their know pattern…one linear and one exponential with speed later? That’s not the known way they represent
Okay you’re combining 2 things. The generation of EMF from a motor free spinning, vs losses when you actively put electricity into the windings. You’re looking at 2 separate calculations and putting them into 1 idea.
You need to calculate these 2 things entirely separately. Because when you start actively generating a magnetic field that is attracting/opposing the magnets, the magnetic strength in the stator is now saturating more than what the free spinning magnets are doing to the stator.
It’s straight forward. Cogging also overlays on the motor torque when powered. There when not powered and also there powered. To do w magnets and iron
Need not be saturating at all
give a good explanation that makes sense and doesn’t contradict what’s know about iron losses. Forget saturation were talking way before then w cogging
Yes, because powered and unpowered, the magnets are still staggered, so there is a time when the magnetic strength is stronger between magnet and stator, and when it’s weaker. This will show whether the motor is under power or not. BUT, this is simply a phenomenon due to the staggering of magnets, but it has no relation to momentum loss.
Here read this
I didn’t read it all but I’m assuming w magnet segments the goal is less eddies in magnets. Sure. Not less cogging though.
There is momentum lost w cogging. Maybe converted to heat maybe not from what I read.
You can make a super motor with thinnest laminations and segmented magnets and it will cog as much. Low eddies though. But eddies are not a noticeable loss at 60 rpm. Not something that will stop ur slow coasting
It’s not a maybe, it’s 100% to heat, because the motor is not near 99% light speed to turn into mass.
The question is how is the heat being generated.
I read somewhere how it need not be a transformation to heat. I don’t have the writing around. I’ll find it and bring it. I don’t have an answer as to what cogging torque is but shoot down eddies and hysteresis as in their normal production we can calculate them pretty well based on erpm and we know this isn’t that normal curve. Vibration doesn’t fit. You all seem to like eddies. Hysteresis someone else. no one can give a solid answer why it’s not net zero to begin with when a magnet is passing iron in a motor.
How about the cored slotted pm motor w all N magnets facing up?
Eddies? Hysteresis? Cogging?
You do know that eddy current can happen in the magnets themselves as they are conductive. If you read page 40-42 of what I linked earlier, it thoroughly describes cogging vs eddy current. You’re calculating the eddy current loss of electrical current through a stator via power input. You never considered that a free spinning motor will heat up the magnets themselves. In fact it goes to mention electrically insulated magnet lamination too.
Eddy current will happen any time a magnet moves past something metal. Regardless of which way it is facing or how the core/whatever is. Drop a magnet through a copper or aluminum tube. It will slow down. Eddy current.
Hysteresis is a description of what causes eddy current. The lagging magnetic field is the source of back EMF.
Perhaps you should look into how a magnet induces EMF any time it moves past a conductive surface, rather than start in a motor.
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Skewed. But I’ll read it
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