Endless Sphere

Punx0r wrote: ↑

Mar 02 2020 5:07pm

Interesting he was cleared of riding without a licence as he seemed to be bang to rights on that one, irrespective of the impact.

Yes, I found that surprising too...

Does England have the legal concept of contributory negligence, where a percentage of the fault can be assigned to the respective parties, or is it all or nothing? Yes, it does. Some aspects of its use have been quite contraversial.... See: http://thecyclingsilk.blogspot.com/2014/12/inquest-into-de...

Balmorhea wrote: The late Val Kleitz of Seattle used to modify antique Bendix 2-speed hubs to function as shiftable fixed/free hubs. That's now a few degrees removed from practical.

Interesting. BSA made a shiftable fixed/free 2 speed hub called the 'DP'. There were cables controls to both sides of the hub.

It was called the 'Fix-Free' drive. You won't find anything about it online though... I still have the leaflet that came with mine.

viewtopic.php?f=28&t=8644

viewtopic.php?f=28&t=8644&start=50

Some background for those not up to speed....:

https://www.bbc.co.uk/news/uk-england-b ... s-49393998

You're on a roll, Lars :) Thanks for the useful references. Interesting how little the resistance between surfaces needs to be to avoid conduction of eddys.... I guess that's why you can get away with a thin oxide layer on stator laminations. With regard to finding the likelihood of serious rotor lo...

Awesome adventure Justin! Thanks for sharing the experience, all the way from conception.

Can't wait to see your hybrid rowing boat! Rowing generator; pedals; batteries; solar panelled roof/sail; propellor............

Topic split to here: viewtopic.php?f=30&t=95487

Topic split at the point where the discussion of eddy currents in the rotor starts. Let me know if it needs any further attention...

Furthermore, I just posted what my friend in the UK has told me several times. That electrical conductivity is not the issue. He just told me that NOT having gaps between the magnets is creating the heating and losses in the magnets in higher RPM motors. Which I just posted here earlier today. He m...

Hi Cole,

It's 8P 24T which is an integer-slot winding.
Best to wind it as a single layer winding to get a winding factor of 1. That means the coil will span 3 slots.
See here for more information: https://www.emetor.com/windings/

Everything needs to be balanced. There has to be enough iron in the teeth to avoid saturation etc.

There's no ideal distance. It varies a bit depending on the scale of the motor. For our uses around 0.6mm to 1.4mm. Obviously, the shorter the distance the greater the flux for a given magnet.

Ok so the end TURN if not contributing to the Pole flux at all or at least significantly can be kept short by having more slots/teeth closer together in the core thus increasing the number of stator slots thus increasing the number aka total active length of the windings increasing the motor torque...

I further suspect that even though the full turn of the coil does not contribute to the Lorentz calculation that this does NOT mean it has no effect, this is merely a side effect of that particular analytical approach to the solution. Both the permanent magnet field, and the coil field exist in the...

Ok now for the end turns...I mean the wire between the coils around a stator tooth ... The entire length of the end turn is ... The circumference of the stator core ... No, that's not what we're discussing in this thread. It's the section of each turn of the coil returning it to the other side of t...

Buk___ wrote: ↑

Mar 18 2018 3:29pm

Look around their site, and see if you can find them referring to their motors as BLDCs. They certainly don't fit most descriptions.

https://www.thingap.com/industries/

Brushless Permanent Magnet Motor Design - Duane C. Hanselman But start with the first chapter of: Electric Motors and Drives - Austin Hughes https://books.google.co.uk/books?id=jjuTYtKokc8C&printsec=frontcover&dq=fundamentals+austin+hughes&hl=en&sa=X&ved=0ahUKEwjlyNaWhZ_LAhVHthoKHaAuDtIQ6AEIJjAA#v=o...

In the interest of balance: http://www.mpoweruk.com/machines.htm

More misinformation http://web.mit.edu/first/scooter/motormath.pdf