Roger Borg Posted December 29, 2024 Posted December 29, 2024 Prefacing that I've not personally dug into the guts of any dc fans, but admit that I always find the spherical design to be alluring. HC, eck, jandus, emerson, ge, fitzgerald (and I imagine others I'm not thinking of offhand), had completely spherical or nearly spherical motor bodies. (Some in this category weren't completely spheres, but more pill shaped or otherwise rounding if noy spherical). Why is this motor body shape generally found on dc/universal fans? Was it a visual cue that it was DC as opposed to AC, and thus a common signifier across brands? Or is there an operational reason this shape is better suited for direct (or universal) current. Similarly, I've noticed DC fans have no (or fewer vent holes). Also curious as to the logic. Thanks... Quote
Michael Bouthiller Posted December 29, 2024 Posted December 29, 2024 I personally have a ball motor K&D Quote
Michael Bouthiller Posted December 29, 2024 Posted December 29, 2024 And all star rite nickel plated fans had a pill shaped motor Quote
Martin Carena-Santiago Posted December 29, 2024 Posted December 29, 2024 A lot of those DC counterparts didn't have cooling vents, as opposed to the AC models that did. Maybe in some cases it was an easier way to cast the housing for fans that already maybe weren't being produced in as high volume as AC counterparts? I will note that my DC Westinghouse Vane still has the same shape as the AC tank, just without any vents and the additional protrusions on the rear housing for brushes. I also have a unuversal frigid with a ball motor. 1 Quote
Russ Huber Posted December 29, 2024 Posted December 29, 2024 https://patentimages.storage.googleapis.com/06/fe/a7/8c268fab78b72b/US627488.pdf 2 Quote
Roger Borg Posted December 30, 2024 Author Posted December 30, 2024 2 hours ago, Russ Huber said: https://patentimages.storage.googleapis.com/06/fe/a7/8c268fab78b72b/US627488.pdf Hi Russ, thanks for the info. After reading, what I still don't follow is how a spherical body is better for the magnetic fields as he claims. Eck says "As the lines of magnetic force act in continuous curves, it has been found by experience that a spherical frame or yoke is conducive to a higher working efficiency," but doesn't elaborate further. Don't all single phase motors, AC, DC, or universal, have similar rotating magnetic fields? His primary point is that it's better for manufacture/assembly, and kinda seems to then throw the efficiency claim on top without substantive supporting references. He goes on to say that spherical construction affords "a circuit for the magnetic currents in which disturbance by mechanical imperfections has been reduced to a minimum." What is considered a "mechanical imperfection"? And back to the original question, why does a spherical case outperform a cylindrical case (which if taken at outer dimensions, a cylinder has more volume than a sphere). Lastly, although this is his patent, it seems Lundell had the shape earlier. (Maybe others I'm unaware of also predate, so is his pattent trying to lay claim to a shape already adopted?) I'm still curious as to how the sphere is better for dc magnetic fields, with the understanding that not all dc models changed shape from their AC brethren (tank, jandus, maybe others). Thanks... 1 Quote
Russ Huber Posted December 30, 2024 Posted December 30, 2024 1 hour ago, Roger Borg said: Hi Russ, thanks for the info. After reading, what I still don't follow is how a spherical body is better for the magnetic fields as he claims. Eck says "As the lines of magnetic force act in continuous curves, it has been found by experience that a spherical frame or yoke is conducive to a higher working efficiency," but doesn't elaborate further. Don't all single phase motors, AC, DC, or universal, have similar rotating magnetic fields? His primary point is that it's better for manufacture/assembly, and kinda seems to then throw the efficiency claim on top without substantive supporting references. He goes on to say that spherical construction affords "a circuit for the magnetic currents in which disturbance by mechanical imperfections has been reduced to a minimum." What is considered a "mechanical imperfection"? And back to the original question, why does a spherical case outperform a cylindrical case (which if taken at outer dimensions, a cylinder has more volume than a sphere). Lastly, although this is his patent, it seems Lundell had the shape earlier. (Maybe others I'm unaware of also predate, so is his pattent trying to lay claim to a shape already adopted?) I'm still curious as to how the sphere is better for dc magnetic fields, with the understanding that not all dc models changed shape from their AC brethren (tank, jandus, maybe others). Thanks... How do you sleep at night, Roger? Quote
Russ Huber Posted December 30, 2024 Posted December 30, 2024 Roger, try not to over analyze the DC sphere and its purity. Eck's field casting has no breaks, seams, or segment halves like Lundell. However, be it Eck or Lundell, it is just a silly small fractional fan motor and both will run just fine to cool you down. No different than the laminated stator DC fans. They work just fine to cool you down. 🙂 1 Quote
Russ Huber Posted December 30, 2024 Posted December 30, 2024 (edited) Pure cast DC frame, Roger. But a Westinghouse DC with drawn steel frame and laminated stator will run just as good. 🙂 Edited December 30, 2024 by Russ Huber 1 Quote
Roger Borg Posted December 30, 2024 Author Posted December 30, 2024 40 minutes ago, Russ Huber said: Pure cast DC frame, Roger. But a Westinghouse DC with drawn steel frame and laminated stator will run just as good. 🙂 I sleep like a baby. Wake up every few hours soiled and bothered. Oh wait, no i don't. Anywhichway, eck was the example you gave as a reason for spheres. In what i read, beyond build efficiencies, the patent pages didn't satisfactorily explain HOW this shape was better for the operation of a DC motor beyond the brief generalities previously mentioned. If it boils down to those manufacturing benefits, so be it, but I am still hoping there is a more sciency understanding out there than what the patent provided. What benefit do AC motors derive from being more cylindrical in form, and DC/universal more spherical or rounded? As always, thanks for putting up with my inquisitiveness. Hope it's not an inquisition. Any motor guys want to chime in? Thanks in advance... Quote
Bill Dunlap Posted December 30, 2024 Posted December 30, 2024 I was under the impression that solid field cores were only used with DC fans. I got a surprise recently when a Marelli I repaired with solid field cores ran just fine on AC. Never say never, I guess. I recommended, however, that it be run at half voltage and DC simply because DC fans run sweeter and cooler than induction motor fans, typically. And I love efficiency and DC motors satisfy in that way. cheers, Bill Quote
Roger Borg Posted December 30, 2024 Author Posted December 30, 2024 27 minutes ago, Bill Dunlap said: I was under the impression that solid field cores were only used with DC fans. I got a surprise recently when a Marelli I repaired with solid field cores ran just fine on AC. Never say never, I guess. I recommended, however, that it be run at half voltage and DC simply because DC fans run sweeter and cooler than induction motor fans, typically. And I love efficiency and DC motors satisfy in that way. cheers, Bill Hi Bill, thanks for chiming in. If DC fans run cooler, seems that explains the no / fewer vents in the motor body. Any feedback on why DC fans run cooler? What about a DC armature / stator vs AC stator / rotor accounts for the reduced heat? I recognize shaded pole AC run hot, and capacitor AC run comparatively cooler and more efficiently, but how does DC compare and why does a commutator motor run smoother and "better"? Many thanks... Quote
Russ Huber Posted December 30, 2024 Posted December 30, 2024 1 hour ago, Roger Borg said: In what i read, beyond build efficiencies, the patent pages didn't satisfactorily explain HOW this shape was better for the operation of a DC motor beyond the brief generalities previously mentioned. Just place your faith and trust in Charles Eck and sleep well. Quote
Russ Huber Posted December 30, 2024 Posted December 30, 2024 41 minutes ago, Bill Dunlap said: I was under the impression that solid field cores were only used with DC fans. I got a surprise recently when a Marelli I repaired with solid field cores ran just fine on AC. Never say never, I guess. Did the tag on the Marelli state alternating current? I had a small Holtzer-Cabot motor that was demonstrated to me by the seller on AC wall current. It ran well for the brief period of demonstration the seller ran it. When I purchased it and saw the tag it was for DC. When I got home and popped the bell it was a cast field. What doesn't change with a DC cast field is the negative effects of AC eddy currents. Quote
Bill Dunlap Posted December 30, 2024 Posted December 30, 2024 I seem to recall it was labled DC, which I assumed was DC only. I only tried it on AC because it was a 220V fan and that seemed odd to me. I also assumed that on 220VDC that thing would have spun itself to death. I'm really just a functional practicioner of these motors rather than an expert. We do have experts here so I'm wondering if they won't chime in and enlighten us. Cheers, Bill Quote
Russ Huber Posted December 30, 2024 Posted December 30, 2024 1 hour ago, Bill Dunlap said: I'm really just a functional practitioner of these motors rather than an expert. We do have experts here so I'm wondering if they won't chime in and enlighten us. Cheers, Bill The more informative segment of the YouTube video regarding the effects of AC eddy currents on an iron core as opposed to a laminated core can be seen starting about 2 minutes 30 seconds in. Quote
Roger Borg Posted December 30, 2024 Author Posted December 30, 2024 2 hours ago, Russ Huber said: Just place your faith and trust in Charles Eck and sleep well. He has a motor company bearing his name, I don't. Yet, unless it is simply magic, I'll still respectfully ask for more than faith alone. Don't all motors create magnetic forces? Aren't all magnetic forces in continuous curves? I'm still wanting for something concrete about what it is about electromagnetism caused by direct current that is better suited by this motor body shape... Quote
Bejon A. Boranian Posted December 30, 2024 Posted December 30, 2024 5 hours ago, Roger Borg said: He has a motor company bearing his name, I don't. Yet, unless it is simply magic, I'll still respectfully ask for more than faith alone. Don't all motors create magnetic forces? Aren't all magnetic forces in continuous curves? I'm still wanting for something concrete about what it is about electromagnetism caused by direct current that is better suited by this motor body shape... ...Ok, I'm totally NOT an expert... That said: Doesn't our planet function like a Huge spherical motor? "Magnetic curves" go in and out. It's a huge magnetic field of inspiring proportions 😎 ... ...Perhaps, the builders of these motors of old, looked no further than the Earth itself for spherical design and proposed benefits. Quote
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