Conclusive proof gearboxes are awesome.

[speedmd]

Hi Luke

Smoking ride against the tesla. WOW. Love to see the setup in person. Looks like you have the power in that setup to top 150 MPH in the quarter given the acceleration 50 -100 meters out of the blocks. Impressive for certain. Love the passenger seating also. Street legal?

http://endless-sphere.com/forums/viewtopic.php?f=6&t=63107&view=unread#unread

 

[liveforphysics]

Hi Luke

Smoking ride against the tesla. WOW. Love to see the setup in person. Looks like you have the power in that setup to top 150 MPH in the quarter given the acceleration 50 -100 meters out of the blocks. Impressive for certain. Love the passenger seating also. Street legal?

http://endless-sphere.com/forums/viewtopic.php?f=6&t=63107&view=unread#unread

It's as street legal as any electric assist bicycle, yet a bit more utilitarian than most with the seating for two now.

Speedmd my friend, it seems a motor misconception you may still have remaining is the nature of KV in a motor. Spend an hour to educate yourself on it, and you will no longer ask questions related to voltage/torque/RPM, and your misperceptions in interpreting simulator data will clear up as well.

Then you will realize, electric drive offers the capability of simply making the torque you want over the speed range you want, from any pack voltage if you design a system around working with that pack voltage. For example, my deathbike could run from 12v and have identical performance, or even higher top speeds or whatever if I chose to build the system around 12v. The system would weigh a few pounds more in conductor bus mass though, and MOSFET power transfer is optimized around ~80vdc right now, so for an ultimate peak performance (torque and speed and power and efficiency etc) build I would be decreasing my system voltage from 28S to ~20S.

As you gain knowledge of the function of an electric motor, the limitations you perceive of the capabilities of a drive-drive topology will be revealed to exist only in your mind and do not exist in reality.

 

[flathill]

torque production is roughl proportional to machine size

while power is unlimited

more power more rotations

when you fly you dont use gearboxes

younsize the motor to the torque you need for ur app

 

[speedmd]

Speedmd my friend, it seems a motor misconception you may still have remaining is the nature of KV in a motor. Spend an hour to educate yourself on it, and you will no longer ask questions related to voltage/torque/RPM, and your misperceptions in interpreting simulator data will clear up as well.

It is not as easy as it sounds. Too many years dealing with gasers I guess and information on the high end stuff is somewhat concealed. I can see that the mid speed range (visually looked like 20- 90 mph) your set up is a rocket and it would cover nicely most of what you would encounter in a road coarse. I understand what your suggesting is ideal with low turn motors and controller that can handle it. A friend that worked in locomotives a bit is saying the same thing, and claiming they push well over 1000 volts into the motors to get the power/speed they need. Wish the type of motor and controllers you are using were on the simulators that I could play with a bit to get a better feel for what your able to get from them. May need to take the plunge on one of those zero motors at some point.

Question I still have remaining is if you were going for a land speed record, would you still suggest you would be best suited with a single speed setup, or would you start to get into eddy current losses that are hard to overcome at the top end of the rpm range or have a motor that is too difficult to properly drive with currently available controllers at lower speeds?

 

[liveforphysics]

It is not as easy as it sounds.

Only until you gain awareness that it is.

I can see that the mid speed range (visually looked like 20- 90 mph) your set up is a rocket and it would cover nicely most of what you would encounter in a road coarse.

I was not WOT until about 40-50mph because what you can't see from the video is that I'm lighting the tire up and fishtailing if I go more than about ~60% throttle for the first 100ft of the track or so. Keep in mind, I didn't configure the bike for drag racing, this is it's kart-track racing configuration where the longest straight section is an 1/8th mile or so, so it's got ample speed overhead beyond what I can use.

I understand what your suggesting is ideal with low turn motors and controller that can handle it. A friend that worked in locomotives a bit is saying the same thing, and claiming they push well over 1000 volts into the motors to get the power/speed they need. Wish the type of motor and controllers you are using were on the simulators that I could play with a bit to get a better feel for what your able to get from them. May need to take the plunge on one of those zero motors at some point.

Yes, using a simulator that features only motors built for the purpose of being the cheapest possible to manufacture solution to make a bicycle move is not representative of what is possible to achieve with properly designed electric drive systems.

Question I still have remaining is if you were going for a land speed record, would you still suggest you would be best suited with a single speed setup, or would you start to get into eddy current losses that are hard to overcome at the top end of the rpm range or have a motor that is too difficult to properly drive with currently available controllers at lower speeds?

If I were going for a land-speed record, I would ABSOLUTELY and EXCLUSIVELY use direct drive. You need as much power as you can deliver to the wheel for top speed, and you also need long duration of sustained high power durability. Adding any stages of loss and added failure modes in that drivetrain would be asking for poor performance and reliability.

 

[speedmd]

Thanks Luke for putting up with my rather thick southern Italian skull. You have me. I'm ready to sip. Where do I find the cool aid. :lol:

cheers

 

[liveforphysics]

Thanks Luke for putting up with my rather thick southern Italian skull. You have me. I'm ready to sip. Where do I find the cool aid. :lol:

cheers

Excellent! It is my pleasure to help raise awareness my friend. It's a duty I do with passion, because I enjoy seeing the revolution take steps in the right direction, the efficient and mechanically simple and robust direction.

You've acquired a thirst for what is the inevitable future of EV drive topology performance.

Now for the tricky part, if you want to taste of this delicious nectar, you have to create it. It's not sold in bottles off the shelf yet, because too many good minds are still dwelling on misconceptions related to overcoming the inherent weaknesses of ICE stuff.

As folks learn to embrace making torque, we will begin to see it bottled on the shelf.

 

[speedmd]

Thanks Luke. Now to D.B. 8.0. Traction / stabilization (keep it straight and not flipping over) control? Also thinking what is needed to keep it accelerating hard all the way to the line (keep the motor driving on a stronger torque curve in the last 1/8) in a electrical "over drive" of some sort. Certainly an interesting challenge on the control side. Look forward to the developments.

cheers

 

[Punx0r]

Then you will realize, electric drive offers the capability of simply making the torque you want over the speed range you want, from any pack voltage if you design a system around working with that pack voltage.

Ahh. This was the missing piece of the puzzle and I now understand the significance of a 1-turn motor. The confusion was caused by playing with relatively high inductance motors for years.

 

[liveforphysics]

Also thinking what is needed to keep it accelerating hard all the way to the line (keep the motor driving on a stronger torque curve in the last 1/8) in a electrical "over drive" of some sort.

Yes, it's currently configured for kart-track racing. I've outlined my plan for it's use as a drag-specific vehicle in another thread, I will repost my drag-specific iteration plan here as well.

It's a 1st prototype and development test motor for what became the 2013 Zero motor. It's an extremely efficient PMAC 3 phase air cooled inrunner. I have fitted, dyno tested and tuned, and raced with a Perm132 (modded), an Agni 95R (brushes setup by Cedric Lynch himself), the big brushless MARS, the 5kW golden motor and the biggest 10kW golden motor.

This motor has higher continous power capability than any 2 of them combined. This motor also isn't saturated even if you pump in enough current to make > 200ft-lbs. (I'm going to be pumping enough current into it to do that soon.)

I'm running a Sevcon gen4 size 6 controller setup with special firmware. It draws >700A off the battery, which is 117vdc fully charged. It's currently a 50Ah pack, but I'm thinking about going 8p 28s with 56 of this 4s Nanotech pack.

http://www.hobbyking.com/hobbyking/stor ... _tech.html

Then removing the heavy duty GP superbike dual disk front end, and replacing it with a light weight bicycle front and brake again. Possibly a road bike fork and aero rim/tire setup. It has no front brake, and for drag I think it's regen is adequate brake alone.

Switching battery and front end should shave ~55lbs, and the second size6 controller and cables will be maybe another 12lbs.
So net reduction in weight of ~40-45lbs, 2x torque and HP, and re-gearing it for ~165mph.


My calculations predict this arrangement should be completing the quarter mile in the ~8's, provided the chassis doesn't fold up under the torque or something silly like that.

This stuff is really not hard to do when you take the simple path. People often make EV drivetrain's complex and fragile with lots of moving parts and associated inefficiency and failure modes and things out of a lack of awareness that it can just be simple, efficient, and robust instead.

 

[speedmd]

Hi Luke

I wish they made a less powerful and thinner pancake (Same diameter with less laminations) version of your motor that would fit easily in a normal BB width. What kind of efficiency are you getting out of it? I can see the D.B. 8.0 going well under 9 seconds with some better launch control and top end dialed. Serious speed!

cheers

 

[liveforphysics]

Hi Luke

I wish they made a less powerful and thinner pancake (Same diameter with less laminations) version of your motor that would fit easily in a normal BB width. What kind of efficiency are you getting out of it? I can see the D.B. 8.0 going well under 9 seconds with some better launch control and top end dialed. Serious speed!

cheers

It's >95.5% peak efficiency. It's efficiency curve is >90% for almost all of the curve (obviously at 0rpm it's 0% efficiency like all motors).

There are no material world limitations on making one fit in normal BB width, it's simply a matter of the market not asking for high performance motors because the market tends to be driven by the cheapest solution to make a bicycle move rather than spending a little extra cost in design/materials to make something good.

 

[speedmd]

Sounds like an incredible power plant. Can you share some details like, turns, pole and tooth counts. Miles had some numbers approaching these in several of the build threads that looked very promising.

 

[kenkad]

It's >95.5% peak efficiency. It's efficiency curve is >90% for almost all of the curve (obviously at 0rpm it's 0% efficiency like all motors).

LFP,
Amazing! Can you post the RPM vs Eff plot for us to see?

Here is an example of Remy's motorcycle engine info.

http://remyinc.com/docs/HVH410R2.pdf

kenkad

 

[major]

Here is an example of Remy's motorcycle engine info.

http://remyinc.com/docs/HVH410R2.pdf

kenkad

Do you know of a motorcycle using that Remy motor? I know a few using the 250 size, but that link goes to the 410 size typically used in buses. I always thought one of those 410 monsters would make a hellofa quick drag bike, but haven't heard about anyone actually doing it.

 

[kenkad]

major,
That motor was brought up in a home built aircraft forum thread and Remy does make motorcycle motors, as you have pointed out. I thought it was worthwhile to reference it because that PDF shows the RPM vs efficiency/torque plot for these advanced inrunner technologies. LFP keeps saying that he has a motor that is >90 % efficient (except at 0 RPM of course) and I thought it would be nice to see such a graph, like in the Remy PDF. Nowdays, it is always easy to say something, but, it is better if we can actually see the proof. Not some simulation (like Miles does from time to time) but actual real data. I have been involved in motor design simulations and the actual data does not typically look the same. I am simply saying that if you make a statement, please be kind enough to show the real relevant data.
kenkad

 

[speedmd]

Hi kenkad

What type of setup is needed to effectively produce the RPM vs efficiency/torque plot. BTW, does Remy make (or possibly entertain making) a narrow alternator size motor that may be suitable for light ebike use? Parts possibly?

 

[major]

What type of setup is needed to effectively produce the RPM vs efficiency/torque plot.

Hi speedmd,

I hope you and kenkad don't mind that I chime in. I've done that type of motor testing at about 100kW and 12,000 RPM. An instrumented dynamometer and power supply are required. The torque sensor alone cost $10k. If you need data on the motor separate from the inverter, then a 3 phase power analyzer is needed.

BTW, does Remy make (or possibly entertain making) a narrow alternator size motor that may be suitable for light ebike use? Parts possibly?

I was fortunate to have a tour of the Remy engineering development facility because they sponsored the Lightning bike. I am bound by the NDA but can address your question. They are a supplier to the OEM automotive and truck/bus market. They have deviated from the traditional approach of ignoring all other potential markets by offering the non-propitiatory design in the 250 size to smaller companies which they deem worthy such as AM Racing. That is how the product ends up in motorcycles and racecars.

I am certain that Remy would not entertain the idea of a new product development unless there was a viable customer with a multi-million dollar product requirement. A better approach would be to see if AM Racing would do it using some existing tooled Remy parts from their alternators. Even that's a long shot IMO.

 

[speedmd]

Thanks Major

Thanks for the test info. Though it would be somewhat out of reach for privateers.

Does not hurt to ask about new motor possibilities/ parts. The alternator size would be the berries. Even if we could re adapt spare/ obsolete parts, it would be killer. 250 size is just way too big for a light weight. The Plettenberg nova series seem to be one of the better choices, but domestic built is what I am hoping to find. Big Astro is not pancake enough, the smaller ones do look nice but a bit small diameter rotor/ high KV and noted cooling short comings.

 

[zEEz]

looks like nobody needs a gearbox anymore, well , pity, I could sell one used
In the end I foresee the gearbox remaining with its ICE and at a certain point it will be time
to restorate the entire bike that in the meantime became an hystorical piece that nevertheless was
and could again reach 130 kmph while using in average 20 km / L. Almost like a modern diesel car :?

Without gearbox I wish could do a semiscale replica of the deatbike Too funny the Tesla race video.
For were I am, considering the actual competition, even 15kW on a light bicycle frame with small double width
Bmx tyre could make the business, if staying below 90 kmph to avoid broken bones

plenty of fun!

 

[onloop]

Firstly let me say I have not yet read the entire 22 pages. Not from lack of interest, mostly due to lack of time.

But already I have a question..... So firstly I apologize if this sub topic/question i raise has been covered already.

My question: Is it possible to make a ESC that can increase the voltage supplied from the battery. A Voltage booster?

Is it called a transimpedence amplifier?

I use 6S, So take the nominal voltage and bump it up by a few (say 3.7 volts) in exchange for capacity. So you have 7S.

Then you can afford to mechanically gear the motors with larger reduction to maximise the torque output. (I'm thinking skateboards here)

However as we still also want to reach high top speed we then can use voltage boost for these times.

However this increase in voltage should only occur when the motor has minimal load.

For example: you are riding up a hill. The motor has lots of load. Then you come down the hill onto flat land and when you are able to travel at max RPM/top speed & when load is minimal/stable & not increasing above a set level, for a period 5 seconds etc, the ESC starts gradually increasing voltage.

Then if increased load on the motor is detected, due to hill climbing, the voltage boost is gradually turned off. Back to normal battery voltage.

Does this technology already exist?

 

[thepronghorn]

What you describe is called field weakening. Higher end controllers have it such as the sabvoton controller described by zombiess in this (motor technology) section of the forum. Basically field weakening uses current in the windings to oppose some of the magnets' field in order to effectively decrease the power of the magnets, which increases the kv of the motor.

 

[onloop]

What you describe is called field weakening. Higher end controllers have it such as the sabvoton controller described by zombiess in this (motor technology) section of the forum. Basically field weakening uses current in the windings to oppose some of the magnets' field in order to effectively decrease the power of the magnets, which increases the kv of the motor.

so does this actually work well? why not have this on all setups...

 

[Miles]

I thought onloop was describing something more like a buck/boost controller? The only one I know of is the Split Pi.

Field weakening, as pronghorn says, works by "adding current" in the d-axis, which reduces Kt, so the motor spins faster for a given voltage.

 

[onloop]

Yes. I was talking about boosting voltage.