## Search found 112 matches

Dec 27 2019 12:55am
Forum: Motor Technology
Topic: Homopolar Switched Reluctance Motor
Replies: 15
Views: 1993

### Homopolar Switched Reluctance Motor

I found this paper about an interesting type of motor. https://fdocuments.in/document/a-new-two-phase-homopolar-switched-reluctance-motor-for-electric-vehicle-applications.html They actually researched it specifically for electric vehicles like ebikes and escooters. It has some interesting features....
Dec 11 2019 2:19am
Forum: Motor Technology
Topic: Non self starting 1-phase induction motor?
Replies: 2
Views: 598

### Non self starting 1-phase induction motor?

I know that a single phase induction motor uses an auxiliary winding 90 degrees apart to allow self starting... My question is, are there any examples of a 1 phase induction motor WITHOUT this? I just want to see what one looks like and study it. Searching online just revealed tons of info about how...
Dec 02 2019 3:14pm
Forum: Motor Technology
Topic: Motor with Electromagnets on Stator and Rotor?
Replies: 2
Views: 1121

### Motor with Electromagnets on Stator and Rotor?

What if you had a normal BLDC DD hub motor, but instead of magnets on the rotor you had another set of electromagnets? To make this work you could have separate batteries spin with the rotor, so no cord would get twisted. I'm imagining an even number of poles on the stater and rotor, which line up t...
Jan 11 2019 1:02am
Forum: Battery Technology
Topic: DIY Super Capacitors, and Robert Murray-Smith
Replies: 31
Views: 8769

### Re: DIY Super Capacitors, and Robert Murray-Smith

But 100 x 18 = 1800, while 10,000 x 1.8 = 18,000. What am I missing here? Anyway I should probably save further general capacitor questions for a different thread so I don’t clutter this one up.
Jan 10 2019 8:31am
Forum: Battery Technology
Topic: DIY Super Capacitors, and Robert Murray-Smith
Replies: 31
Views: 8769

### Re: DIY Super Capacitors, and Robert Murray-Smith

No, 278Wh would take at least a quarter of an hour (closer to 20-30 minutes, actually, due to current falling off as voltage increases) on a 1kW charger (278Wh / 1000W = 0.278h) Yeah no idea why I said under 5 minutes, it’s clearly 15+ like you said. No, it's still the same wh/L, because it's at 1/...
Jan 08 2019 1:59pm
Forum: Battery Technology
Topic: DIY Super Capacitors, and Robert Murray-Smith
Replies: 31
Views: 8769

### Re: DIY Super Capacitors, and Robert Murray-Smith

Thanks for the explanations on series vs parallel, I think I get it now (mostly at least). Just like to point out Robert has posted a new video showing off a production ready capacitor of his (though in prototype packaging) https://youtu.be/s0ryom-E7u0 Each cell is 1000F and 1.8v. He’s arranged 10 i...
Dec 05 2018 11:22pm
Forum: Battery Technology
Topic: DIY Super Capacitors, and Robert Murray-Smith
Replies: 31
Views: 8769

### Re: DIY Super Capacitors, and Robert Murray-Smith

I'v also heard that, about how capacitors do not increase the energy capacity when in series . If anyone has an extremely simple explanation for why that is, i'd love to hear it (was confused when reading other explanations). If capacitors were to power ebikes for example, wouldn't you want to devel...
Dec 04 2018 5:39am
Forum: Battery Technology
Topic: DIY Super Capacitors, and Robert Murray-Smith
Replies: 31
Views: 8769

### Re: DIY Super Capacitors, and Robert Murray-Smith

Good points. I was kind of exaggerating/generalizing a fair amount and probably should have mentioned that. Though in practice i think some of my points would hold true in a very general sense. For example charging may not be instant but it's still extremely fast and probably limited by the power so...
Dec 04 2018 1:46am
Forum: Battery Technology
Topic: DIY Super Capacitors, and Robert Murray-Smith
Replies: 31
Views: 8769

### Re: DIY Super Capacitors, and Robert Murray-Smith

I'v also followed him for a while. He's recently posted some videos showing his new space he's setting up for producing batteries to actually sell. His initial plans were to make a more automated setup with expensive equipment, but ended up going for a more manual approach. It seems the building is ...
May 10 2018 11:49am
Forum: Motor Technology
Topic: Single phase PM hub motor?
Replies: 3
Views: 689

### Re: Single phase PM hub motor?

If I understand correctly, once manually started it would run poorly at low rpm, mainly due to high torque ripple? If so wouldn’t adding more poles help? Assuming you could get it running smoothly/quietly enough, and didn’t mind no self starting, wouldn’t you end up with a much simpler and more powe...
May 10 2018 11:07am
Forum: Motor Technology
Topic: Single phase PM hub motor?
Replies: 3
Views: 689

### Single phase PM hub motor?

Although I’m still very noob, I like researching and learning about different motor types and how they work... For example this image I found which I believe is a single phase PM out-runner. But I have a few questions... https://i.stack.imgur.com/ip5PT.jpg - Woundn’t this motor provide very high tor...
May 04 2018 4:54am
Forum: EBike General Discussion
Topic: 1 Series Ebike?
Replies: 2
Views: 347

### 1 Series Ebike?

I'm wondering just out of curiosity, would it be theoretically possible to make a 1 series ebike? Let's say you had a 500w motor, so with 3.7 volts you would need 135 amps. Is it possible to design an ebike motor (including hub motors) to run on this voltage, and could the whole thing work, why/why ...
Jan 07 2018 1:22am
Forum: Motor Technology
Topic: Switched Reluctance Motors
Replies: 50
Views: 8058

### Re: Switched Reluctance - Ideal for DD Hubs?

If self-starting isn’t required (which I would argue is the case for ebikes) would single phase not have some benifits for SR hub motors? I’m a total noob but I was wondering, would you not get better power (utilizing all poles at once), more balanced forces for less vibration and noise, and simpler...
Mar 29 2017 4:22pm
Forum: Motor Technology
Topic: Switched Reluctance Motors
Replies: 50
Views: 8058

### Re: Switched Reluctance - Ideal for DD Hubs?

Thanks I've search the website already and read most of these. I didn't seem to find a good explanation for why they aren't made, and just wanted some more opinions on their potential as dd hub motors.
Mar 29 2017 1:22pm
Forum: Motor Technology
Topic: Switched Reluctance Motors
Replies: 50
Views: 8058

### Switched Reluctance Motors

I have been learning about various kinds of motors including switched reluctance. It seems like they could make the ideal direct drive hub motor... Their advantages over pm motors include: - 0 drag when off/coasting - high efficiency over a much broader speed range (great for low rpm) - no magnets t...
Mar 28 2017 7:52pm
Forum: Motor Technology
Topic: Rotating windings?
Replies: 5
Views: 1006

### Re: Rotating windings?

If the bearings could do the job, maybe you could do a design with 2 electromagnetic rotors outside and a permanent magnet stator inside, and make each rotor 1 phase for a 2 phase motor. That way you won't need electronics inside the motor to direct the electricity after it passes the bearing. Hopef...
Mar 28 2017 7:22am
Forum: Stand-up EScooter/ESkateboards
Topic: 250w hub motor scooter mod log
Replies: 103
Views: 25408

### Re: 250w hub motor scooter mod log

Cool project, same idea I want to accomplish with the 2 hub motors. Those controllers are monsterous in size though, I bet if someone custom built a small single controller the size could come WAY down.
Mar 27 2017 3:14am
Forum: Motor Technology
Topic: Rotating windings?
Replies: 5
Views: 1006

### Re: Rotating windings?

What about using bearings to send electricity to the windings, would it be possible?
Mar 24 2017 3:06am
Forum: Stand-up EScooter/ESkateboards
Topic: Cogless dd scooter project
Replies: 6
Views: 1239

### Re: Coreless halbach scooter project

Well maybe a coreless axial halbach motor would actually have heat problems after all, so I'm looking at other options too. I have been trying to find information on induction and switched reluctance hub motors, but haven't found much (except for a post about a larger induction motor being built, wh...
Mar 18 2017 2:21am
Forum: Motor Technology
Topic: Rotating windings?
Replies: 5
Views: 1006

### Rotating windings?

I have an interest in coreless axial hub motors which are known to not tolerate heat well because of having no iron. I was thinking of how to improve this, and was wondering if there's a way to have the windings rotate with the wheel. That would mean they can directly transfer their heat to the case...
Mar 08 2017 12:56pm
Forum: Stand-up EScooter/ESkateboards
Topic: Cogless dd scooter project
Replies: 6
Views: 1239

### Re: Coreless halbach scooter project

My reason to go coreless, and one of the biggest differences to current scooters I've seen, is to have no cogging. It would roll freely like a normal kick scooter, meaning you could use it manually and have the ability to coast when using the motors instead of needing to constantly use the throttle....
Mar 07 2017 9:00pm
Forum: EBike Technical
Topic: Motor braking questions
Replies: 13
Views: 1155

### Re: Motor braking questions

For "eabs" wouldnt the motor efficiency when braking be the same/similar as when accelerating (when looking at the same vehicle speed) meaning when the motor is braking, it will become less effecient the slower you're going? If so stopping completely would only create as much heat as accel...
Mar 07 2017 4:35pm
Forum: Stand-up EScooter/ESkateboards
Topic: Cogless dd scooter project
Replies: 6
Views: 1239

### Cogless dd scooter project

Hi I'm making this post to discuss and ask questions about an electric kick scooter project I would like to research and build. Ever since I first saw electric gopeds (chain transmission) and small electric hub motors, I imagined making an electric kick scooter that was almost indistinguishable in l...
Mar 06 2017 3:52pm
Forum: EBike Technical
Topic: Motor braking questions
Replies: 13
Views: 1155

### Re: Motor braking questions

I'm trying to educate myself for a project I have in mind. It's actually for a kick scooter not an ebike but the principals are basiclly the same. I would like to eventually design and build my own motor for the project.
Mar 06 2017 3:26pm
Forum: EBike Technical
Topic: Motor braking questions
Replies: 13
Views: 1155

### Re: Motor braking questions

Ahh I see, so there's basically there's 3 kinds of electric braking. - Regenerative (Works as generator, charges battery, doesn't work with full battery) - Degenerative (Attempts to spin backwards, drains battery, doesn't work with empty battery) - Thermal (Generates heat like mechanical brakes, no ...