Search found 10716 matches

by Miles
Nov 09, 2017 4:43 pm
Forum: Motor Technology
Topic: Motor comparison spreadsheet
Replies: 548
Views: 35179

Re: Motor comparison spreadsheet

Just an idea here but since we've now added the ability to input a custom motor on the ebike simulator page ( see https://endless-sphere.com/forums/viewtopic.php?p=1324922#p1324922 ), you could in principle add a column to this spreadsheet that uses the string and math functions to produce a direct...
by Miles
Aug 23, 2017 4:21 am
Forum: Motor Technology
Topic: Optimal Hub Motor design? Break down of BionX D-Series
Replies: 69
Views: 3240

Re: Optimal Hub Motor design? Break down of BionX D-Series

Do you think the values are realistic, or to good to be true? They are undoubtedly on the optimistic side. It was never meant to be an accurate predictor of performance. Justin's simulator is much better for that, especially after he's tested the motor on his dyno. The spreadsheet is still useful a...
by Miles
Aug 22, 2017 1:51 am
Forum: Motor Technology
Topic: Optimal Hub Motor design? Break down of BionX D-Series
Replies: 69
Views: 3240

Re: Optimal Hub Motor design? Break down of BionX D-Series

Great thread! Thanks madin88

I've entered all your data into the Motor Comparison Spreadsheet (see attached). It's the entry in the second row. You can change the values in the columns with a white background.
by Miles
Jul 07, 2017 10:23 am
Forum: Motor Technology
Topic: Idiots guide to rewinding Revolt 120 pro
Replies: 295
Views: 15849

Re: Idiots guide to rewinding Revolt 120 pro

@Miles, what would be your educated guess for improvement by segmenting the magnets? What magnitude of change can be expected under the current circumstances with larsb's revolt? It really is a guess but, I would have thought 50% reduction in rotor losses should be achievable... Lars has obviously ...
by Miles
Jul 07, 2017 8:30 am
Forum: Motor Technology
Topic: Idiots guide to rewinding Revolt 120 pro
Replies: 295
Views: 15849

Re: Idiots guide to rewinding Revolt 120 pro

madin88 wrote:exactly! halbach motors usually have a high peak ETA and can do high RPM, but the torque is quite low (there is no stator iron)..
You can design to achieve parity re. airgap flux density. It's more that the benefits, if any, wouldn't be worth the trouble, for a motor like this....
by Miles
Jul 07, 2017 4:41 am
Forum: Motor Technology
Topic: Idiots guide to rewinding Revolt 120 pro
Replies: 295
Views: 15849

Re: Idiots guide to rewinding Revolt 120 pro

I've been reading up on rotor material and it seems like rotor backiron material also does matter for the losses. From the research papers i've come across it's clear that the losses can be large in rotor backiron but how extreme or representative their researched motor types are i can't judge. Som...
by Miles
Jun 12, 2017 3:44 am
Forum: Resources & EV Related Parts and Services
Topic: Power calculator
Replies: 33
Views: 23422

Re: Power calculator

Thanks for the feedback. Do let me know if any errors surface during use.

I saved it as an Excel file using Libre Office.
by Miles
Jan 09, 2017 12:08 pm
Forum: Motor Technology
Topic: Idiots guide to rewinding Revolt 120 pro
Replies: 295
Views: 15849

Re: Idiots guide to rewinding Revolt 120 pro

Have you wound many stators with that type and size of wire? What tools and procedure would you advice? I don't have much winding experience, I'm afraid. The 2:1 ratio wire is definitely easier to work with than square wire, which does its own thing despite your best efforts to keep it from twistin...
by Miles
Jan 09, 2017 12:02 pm
Forum: Motor Technology
Topic: Idiots guide to rewinding Revolt 120 pro
Replies: 295
Views: 15849

Re: Idiots guide to rewinding Revolt 120 pro

Lars, PM me your address and I'll put a piece in the post. I bought some to see if it would be feasible to wind my 36t inrunner with. It wasn't. Inrunners are more tricky to wind than outrunners. They usually require greater manipulation of the wire so, work hardening of the copper is more of an iss...
by Miles
Jan 08, 2017 5:50 am
Forum: Motor Technology
Topic: Idiots guide to rewinding Revolt 120 pro
Replies: 295
Views: 15849

Re: Idiots guide to rewinding Revolt 120 pro

Lars,

I have a coil of the wire that you're intending to use.

It measures 2.65mm x 1.35mm including the insulation.

I could send you a piece to play with, if that would help.
by Miles
Jan 02, 2017 9:48 am
Forum: Motor Technology
Topic: Open Source DIY non-hub motors
Replies: 55
Views: 4529

Re: Open Source DIY non-hub motors

spinningmagnets wrote:So I gues we have to choose which compromise we hate the least?
Right. That sums up motor design!
by Miles
Jan 02, 2017 5:19 am
Forum: Motor Technology
Topic: Open Source DIY non-hub motors
Replies: 55
Views: 4529

Re: Open Source DIY non-hub motors

Ron, There are examples of that configuration in the link that I posted. If the teeth are separated, the body of the tooth acts as a lever in transfering the rotational force to the joint but you can take the advantage of using grain-oriented steel. If the tooth tips are connected together, you get ...
by Miles
Jan 01, 2017 3:34 pm
Forum: Motor Technology
Topic: Open Source DIY non-hub motors
Replies: 55
Views: 4529

Re: Open Source DIY non-hub motors

Thanks Miles. When you say "sufficient material in the yoke to make interconnection", does that mean that a larger yoke cross sectional area is needed for a segmented stator than a one-piece stator? It's more that it sets a lower limit. For mechanical purposes (some kind of joint for registration e...
by Miles
Dec 31, 2016 1:58 pm
Forum: Motor Technology
Topic: Open Source DIY non-hub motors
Replies: 55
Views: 4529

Re: Open Source DIY non-hub motors

Cool video. I like the idea of the separately wound segments. Interesting that the stator tooth tips are non-existent to allow this type of assembly. Perhaps the motor design experts can chime in on that... Looks like the coils are only retained at the end turns (but all that glue holds it together...
by Miles
Dec 26, 2016 3:33 am
Forum: Motor Technology
Topic: Various types of dc motors for traction application
Replies: 9
Views: 399

Re: Various types of dc motors for traction application

ElectronS wrote:is there a thread here or calculator that tells you how to size motor for weight , incline angle , speed and most importantly wheel friction ???
https://endless-sphere.com/forums/viewt ... 55#p312555
by Miles
Dec 09, 2016 1:31 pm
Forum: Motor Technology
Topic: Motor Design Software
Replies: 7
Views: 357

Re: Motor Design Software

MotorCAD is the industry standard for thermal analysis of motors but they now have an electromagnetic module that works in conjunction. All the commercial software is extrmely expensive. I would rough out the design in Emetor before choosing anything more sophisticated.
by Miles
Dec 07, 2016 4:52 am
Forum: Motor Technology
Topic: FEMM Help needed
Replies: 7
Views: 342

Re: FEMM Help needed

I can't get my torque ripple below 12.5%. I'm also unsure if I should bother trying to skew the stator half a tooth. If you post your simulation here, we can make suggestions. I got torque ripple at nominal torque down to 0.3% when simulating my design. There are a lot of factors.... Anyway, low to...
by Miles
Dec 02, 2016 9:38 am
Forum: Motor Technology
Topic: FEMM Help needed
Replies: 7
Views: 342

Re: FEMM Help needed

I've only used FEMM for magnetic circuits. Now I do all of my motor design in Emetor. Unless your design requires an IPM rotor, I'd recommend you try it. https://www.emetor.com/
by Miles
Nov 05, 2016 7:56 am
Forum: Motor Technology
Topic: Seeking Motor Designer
Replies: 24
Views: 1107

Re: Seeking Motor Designer

Altair wrote:...which goes against my hope of trying interlocking individual poles on the stator, à la Transmagnetics.
Indeed...
by Miles
Nov 05, 2016 2:40 am
Forum: Motor Technology
Topic: Seeking Motor Designer
Replies: 24
Views: 1107

Re: Seeking Motor Designer

Increasing the pole count allows a reduction in the cross sectional area of the active material needed for the flux path in the stator and rotor yokes.
by Miles
Nov 04, 2016 3:15 pm
Forum: Motor Technology
Topic: Seeking Motor Designer
Replies: 24
Views: 1107

Re: Seeking Motor Designer

Altair wrote: The motor specs are:
Mid-drive in-runner design
1250W rating continuous
Rated for 44-48V
Kv of 30 to 35
Stator O.D. 5.06"
Low-weight design
Hi Altair,

So, it will run at up to 1500 rpm and requires the ability to produce around 9 Nm of torque continuously.

What does "low weight" mean, to you?
by Miles
Aug 12, 2016 2:20 am
Forum: General Discussion
Topic: Astronomical Photography
Replies: 5
Views: 237

Re: Astronomical Photography

I live a few minutes walk from the Old Royal Observatory in Greenwich. Every year they host the exhibition of the winning entries in the Astronomy Photographer of the Year competition. http://www.ibtimes.co.uk/astronomy-photographer-year-2016-spectacular-images-inspire-you-enter-prestigious-competit...
by Miles
Jul 29, 2016 3:35 pm
Forum: Motor Technology
Topic: help me chose a motor for my electrathon racer
Replies: 20
Views: 1357

Re: help me chose a motor for my electrathon racer

Unfortunately, I am on a computer that does not have the space to install Open Office and Excel keeps 'fixing' your .ODS file by removing the equations,....... My mistake again.... There should always be an .ODS and an .XLS version in the first post of the thread. I seem to have uploaded the .ODS v...