Le Toy II electric street bike

[AussieJester]

With the energy it takes to produce a battery, ship a battery, plus the charging energy, I can't say that I feel it is more "green" than an efficient guzzler. Would be an interesting study if you are into carbon footprints.

"environmentally friendly" disposal of used cells would have to be added to the list too wouldnt it?

You saw this right?

Imagine that motor on your next machine!!!, Imagine that motor on your next machine!!!

Nope haven't seen it have zero interest in AC motors Safe even less if it weighs 36lbs, Perm motor is lighter has more power and probably a **** site cheaper. If you can find a AC motor that weighs lil more than a can of coke but smaller size has ~8hp and cost under 150 bucks im all ears till then i will use the motor i have that HAS the pre-listed specs

KiM

 

[safe]

The stock RD400 motor (from the old days) produced about 43 hp and required a sturdy frame and wheels to deal with the horsepower. With aftermarket pipes the power was more like 60 hp. Bikes these days make 100+ hp.

That AC Induction motor has 36 peak hp and so the reality is that it would be literally too much power to handle. Your parts would break, wheels would pull out their spokes, chains break, etc. So it's unrealistic because of too much power. (great power-to-weight ratio of 1lb to 1hp)

What is needed is a 10 lb AC Induction motor that can put out a few hp and have a nice wide powerband at 48 volts. (no geardowns, no multispeed gearing needed)

Hey... that's what I'm working on...

You are correct though... there are no AC Induction motors that are "stock" that will work right now for what we want to do... but it does point the way to the potential. The power-to-weight of industrial motors is deceiving people into believing that it isn't possible. (they were never designed with weight or peak performance in mind)

What is the power-to-weight ratio of a brushless permanent magnet motor?

5lbs for 5hp? ...if so then you are getting about the same performance.

AC Induction motors "will happen" it's just a question of "when".

(the physics supporting it is too strong to think otherwise... of course... this is assuming that we all don't give up on electric in a few years like in the 1970's)

 

[johnrobholmes]

A quality PM bldc motor made for performance will have about 2 to 2.2hp per pound at continuous ratings, a shade over 1hp/lb at peak efficiency, and peak power will depend on batteries and controller more than the motor.


Induction will happen if we get controllers and motors mass produced. The attraction to induction motors is the low cost contruction and low cost controllers. Unless scale of economy gets into our niche, they may not materialize. Typically you can expect about twice the motor weight in an induction motor vs PM bldc for an equivalent performance.

 

[safe]

Those old industrial AC Induction motors were designed for the shop floor, not EV's. What seems to be happening is that AC Induction motors are being rediscovered because if you design them for performance they equal the permanent magnet motors on a power-to-weight basis, but then you get the added powerband width. AC Induction motors can have twice the powerband width that permanent magnets have. For ebikes this is especially good news because... think about it... what are the issues we constantly deal with:

The need for geardown units to take rpms from thousands to hundreds.

The need for multispeed gearing (at least two) in order to offer peak performance at both top speed and on hill climbs. (on my old bike I have six speeds and that doesn't seem like enough)

...since we would normally want to run the motor power through a bicycle derailler things are actually worse because you have to first gear the motor down to pedal speed, then back up again for the rear wheel. Every time you do geardowns you lose a few percentage efficiency. (5%)

Also another thing is that the efficiency of AC Induction motors is tied not to motor rpm, but to load. Higher loads are more efficient than lower loads and for that reason the "traction motor" behavior adds to the benefits. (you can hold the throttle wide open and not have to worry about being inefficient)

--------------------------------

One might say that "in theory" the permanent magnet offers a lower power-to-weight ratio, but with the added losses for the geardown, the weight and the complexity "in practice" it never works as well as "in theory". As a completed unit the AC Induction motor looks to be the better solution... though it's by no means easy to attain with what is out there now.

Did you see the link?

http://www.greenmotorsport.com//products_and_services/3,1,388,17,12958.html

...the state of the art is now roughly 1 lb per 1 hp. (peak)

An industrial motor might weigh 50 lbs for only 2 hp, so that's 25 lbs per 1 hp and so the difference between the old industrial motors and the high tech ones is a ratio of 25 to 1. If nothing else that's an impressive improvement.

(this is why you just can't install an industrial motor into an EV... the performance is really awful for the weight)

Anyway... I'll get off my soapbox... but at least take a look again at AC Induction motors as an option.

You also might study these guys:

http://www.chorusmotors.com/technology/index.shtml

...they specialize in high performance small sized AC Induction motors using higher phases. Very interesting stuff. (download their demo)

http://www.chorusmotors.com/technology/simulator.shtml

 

[johnrobholmes]

...AC Induction motors ....equal the permanent magnet motors on a power-to-weight basis, but then you get the added powerband width.

No they don't. You lose flux density without magnets. Copper coils just can't compete with the flux of a magnet, thus you need more copper to equal the same power capability. Your 1hp per pound peak is way off a PM motor. I wonder how many HP peak a 50lb PM motor would have?


I'm not trying to shoot down induction motors here, I am just being real. Sure they have benefits, but they are nowhere near the power density of a PM motor.

 

[safe]

I'm not trying to shoot down induction motors here, I am just being real. Sure they have benefits, but they are nowhere near the power density of a PM motor.

I think you have accepted a kind of "gossip" as truth. The AC Induction motor can achieve very high power levels on a power-to-weight basis if you design for it.

Think about it...

...in the old days (50 years ago) they built these electrical motors for the shop to run things like conveyer belts and stuff. There was no motivation to produce high power and low weight motors.

Check the power-to-weight on this motor:

http://www.greenmotorsport.com//products_and_services/3,1,388,17,12958.html

...GreenMotorSport started with a PM motor and set records with it, but now they are "moving up" to AC Induction motors.

Do racers that want to win choose technology that does not give an advantage?

...my advice is to rethink your "gossip".

PM Motor : 11 kg (24 lbs) - 9kW (12 hp) ~ 2 lb per hp

AC Motor : 15 kg (33 lbs) - 18kW (24 hp) ~ 1.4 lb per hp

 

[johnrobholmes]

If you would take the owner of Castle Creations, the head of my IMSE engineering department, and a few motor manufacturers as "gossip"- then sure I will accept gossip as truth. I have been researching induction motor for years Safe, for practical application and production. The bottom line is that they are heavier for a given power, and more expensive than PM motors in our target size because of low to nil production volumes.


PM is lighter, induction has a broader power range. Have I not already stated that both have their inherent advantages? You don't read what I say. Now stay out of my threads and stop polluting them with off topic dribble that you have stated before.

 

[safe]

I didn't realize this was your thread. My apologies.

(still, GreenMotorSport seems to have pulled it off... maybe they are lying?)

 

[johnrobholmes]

Back on topic here (after safe realized that PM motors are indeed of higher power:weight ratios and started multiple threads on them )

I got the motor mounted up for a RC style power system. I will be using a Castle ICE HV160 for now while an EV controller I am developing is in design phase.

Power system:
Astro 3010-6
12s 10ah or 20ah zippy lipo
ICE hv160
Magura throttle
Home made DSP for throttle to PWM converter
Hyperion 12s charger or raw DC power supply for charging
Battery Medic devices for balancing


I also laced up a matching rear 17" motorcycle wheel for it, I think it looks boss and I will be keeping it this way. A shot with 26" tires is in there for comparison.

All I need to do is tidy up the wiring, make a battery rack, and get chain tensioners and chain lines dialed in. And a rear brake would be handy

 

[Bobocop]

I didn't realize this was your thread. My apologies.

What is that suppose to mean ?
Are you saying that if it was my thread instead of johnrobholmes's you would try to get attention from it ? Is that what your saying ?

Your always looking for attention Safe.
Even if it wasn't his thread, would you still not get in there? (because you need attention, you want to be above everyone else)

I didn't realize this was your thread.

Why not just stay out of other peoples threads, unless you have something good to say, About Their Threads, AND NOT TRY TO PULL PEOPLE TO YOUR IMAGINARY THREADS. (15 Posts And then say OK i'm going on to something else)

johnrobholmes, do you have any pics of it?

EDITED: OK, Sorry, i got the links to the pics (above)
Do you get any vibration while riding from the motor being in that spot ?