20kW Powerstage for "Infineon" 12 mosfet Controller
- Thread starter h0tr0d
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johnrobholmes
10 MW
He has a good point. You won't be able to match acceleration with gears above 1/2 the wheelspeed of your 20kw motor. Lets assume the 20kw motor is geared for 50 and the 10kw motor has first gear of 25 and second gear of 50. In first gear the 10kw motor can match acceleration in a perfect world, in second gear the acceleration will be half as strong as the 20kw motor. No matter how you slice it, you can only meet or beat the 20kw in acceleration with a 10kw at 1/2 the rollout or slower.
h0tr0d
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johnrobholmes said:
20kW will get me to my performance goals, given my foreseeable aerodynamic losses and weight objective.
The "3 speed box" is not THE solution, it's part of the package to make my goals come true. From my estimates, motor and controller limited to 150 phase Amps are cheaper, by a significant margin, then a 600~1000 transient amps motor and controller. With the saved money a gearbox, with all the associated efficiency benefits.
johnrobholmes said:
All of the above. The EV revolution needs all those requirements. Power density above all.
h0tr0d
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johnrobholmes said:
Arlo1 said:No matter how many gears you have a 10kw motor can't accelerate faster then a 20 kw....... I am lost in how you think this is going to work better maybe the thread should be how do I make the worlds fastest bicycle even then Luke will woop you every time
An example you both understand:
Honda CBR 600 120hp using all the gears available.
Kawasaki ZX 14R 200hp using ONLY 4th gear.
So topspeed is around 250km/h in both bikes.
Who wins a drag race?
You are comparing oranges to applesh0tr0d said:
First electrics Have full torque at 0 RPM
Second the motor of the ZX1400 might lonly weigh a bit more then the 600 and still has a tranny
SO take the motor of the ZX1400 and give it no tranny removing the weight locking it with one gear which is = to 4th then make it have full torque at 0rpm
Remember the ZX1400 needs to rev to get to its torque range. But if it had all the torque at 0 rpm it would be different. Then make sure the amount of the weight you added in the tranny of the 600 = to the weight of the more power you get from the 1400.
The reason a lot of Big cars for racing use trannys is because the motor and controller doesnt exist to make up for the weigh of the tranny so they use the best motor controller they can build and use a tranny to make up for it.
Tesla only needs a certain top speed they are not here to set land speed records they are here to sell cars.
h0tr0d
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Arlo1 said:
Arlin, you've made your point. You either don't understand or don't want to understand because you are building a single speed bike. Fine by me, I've tried my best. I know I'm right on this one.
Please let's NOT discuss this further here.
If you would like start a new thread on this matter, i'll participate.
John in CR
100 TW
h0tr0d said:
Five seconds to 62mph and 93mph top end. I can do that easier without a tranny than with one. With a 120lb rider, high voltage brushless controllers, and very good aero it would be a piece of cake.
The point you're missing h0tr0d is that ICE powered vehicles have gearboxes because they need them. I can see a use for a 2 speed for an electric, maybe a 3rd special granny gear, but only, as someone stated before, if an adequate isn't available. Tesla found out the hard way because the gearbox needed for an electric needs to be far stronger than one for an ICE because the torque curve is totally different, so it's better to invest that weight in more motor instead.
I race my ebike against motorcycles on almost a daily basis. I back off at 80kph because it's not appropriate to go faster in these areas and my acceleration tapers off a lot more above 80 anyway. Of course I don't try against sports bikes, but I do beat a lot of bikes I shouldn't. When I get them is when they shift to 2nd where their poor shift and loss of torque bites them in the ass, because I'm just getting to peak power and my bike just keeps pulling continuously without interruption. Most of the time it's against little 110, 125, 175cc etc cheap delivery motos that are everywhere down here, and they really have no chance. It's funny to hear them behind me trying to wind it out and then I hear their sound fall off sharply when they give up. They really have no chance when the only time they meet or beat my torque at the wheel is in first gear for an instant while the motor passes thru it's narrow prime band.
My efficiency may have a prime band, but like Arlo1 was trying to impress upon you, my full torque starts at 0 rpm. Gearing an electric motor properly is only for the launch, and you add to top speed by adding voltage as long as your motor is up to the power. Get the "gearing" right and size your motor right, and then you get both in a single speed. Look at LFP's Deathbike. It's a single speed, has WAY more torque at launch than he can possibly use, and it will also do 100mph. That's because he has a big mofo moto, with a controller and battery pack capable of feeding it. No matter what multi-speed you come up with he will absolutely slaughter it to 100kph, because no matter how well you shift to 2nd, he will be gone when you do. That's you just halved your torque at the shift (or whatever the gearing change is), and his torque just keeps pulling. When you have a powerful ebike it's that continuous pull that is so addicting.
John
Tranny's in EV can be usefull. I found a german article about it thats shows that gearboxes increases efficiency and acceleration. Here is the link: http://www.heise.de/autos/artikel/Doppelkupplungslos-mit-eDCT-1802337.html maybe you can read it if you use google translate.
The gearbox/no gearbox discussion that has been ragin in every thread of ES is starting to look dumb. Facts are drowned down by anectdotes.
Firstly, Tesla use a induction motor, this doesn't have a constant V/f like a permanent magnet motor. A gearbox don't have the same appeal in Tesla's case.
Secondly, a gearbox adds power and efficiency to a permanent magnet motor system (inverter + motor). Remember that power [W] is given by torque [Nm] and angular speed [Omega]. You can produce whatevermuch torque you want, if you don't have any angular speed - there isn't any power behind it.
Thirdly, "awesome electric torque kills gearboxes". No. ICE torque production is rougher in terms of peak torque, not that it really makes a difference. Size the gearbox correctly, use the right lubricants and you will not have any problems. I've sized wind-turbine gearboxes - they have in the order of 1400000Nm on the shaft. Compare that to your ~250Nm.
Fourthly, Luke's bike will be beaten with time. It is allways just a question about time. As Luke has stated himself, the way he reaced xx mph was with brute force, explaining that the same could be done with aero and 2kW. I don't think he's overly happy about being idolized, but that is pure speculation on my part.
Firstly, Tesla use a induction motor, this doesn't have a constant V/f like a permanent magnet motor. A gearbox don't have the same appeal in Tesla's case.
Secondly, a gearbox adds power and efficiency to a permanent magnet motor system (inverter + motor). Remember that power [W] is given by torque [Nm] and angular speed [Omega]. You can produce whatevermuch torque you want, if you don't have any angular speed - there isn't any power behind it.
Thirdly, "awesome electric torque kills gearboxes". No. ICE torque production is rougher in terms of peak torque, not that it really makes a difference. Size the gearbox correctly, use the right lubricants and you will not have any problems. I've sized wind-turbine gearboxes - they have in the order of 1400000Nm on the shaft. Compare that to your ~250Nm.
Fourthly, Luke's bike will be beaten with time. It is allways just a question about time. As Luke has stated himself, the way he reaced xx mph was with brute force, explaining that the same could be done with aero and 2kW. I don't think he's overly happy about being idolized, but that is pure speculation on my part.
h0tr0d
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True story...Teh Stork said:
"adds power and efficiency" BECAUSE of angular velocity!!!! Since we are sharing knowledge, let's be accurate.
Let's look at the graph: Gears vs no gears, constant torque same value on both. Since one uses gears, it can have greater speed at the motor for the same speed at the wheel. therefore, more power at the wheel.
True story again...
And let's stop the comparisons between my 20kW ebike and the 80kW Luke's monster...
That graph must be an automatic transmission with 0 losses?
Or something that can grab the next gear without releasing the first one like a RC nitro car tranny?
At the end of the day if you guys want to work hard on proving or trying to prove a different way and find some gains to be had thats a good thing. I base my knowledge off of real world experiance but there is always more testing to be done and when I get bored because everything is to perfact I will look for more testing to continue to push the envalope. Do you think you would try to prove use wrong if we didn't tell you that was the wrong way
Or something that can grab the next gear without releasing the first one like a RC nitro car tranny?
At the end of the day if you guys want to work hard on proving or trying to prove a different way and find some gains to be had thats a good thing. I base my knowledge off of real world experiance but there is always more testing to be done and when I get bored because everything is to perfact I will look for more testing to continue to push the envalope. Do you think you would try to prove use wrong if we didn't tell you that was the wrong way
999zip999
100 TW
Why is everyone picking on Luke ?
He just wants to go for a ride with his son on the weekend.
He just wants to go for a ride with his son on the weekend.
Thud
1 MW
That made me laugh!
999zip999
100 TW
Just triing to bring some cali. sun to a snowy Mich. day. That you Thud, gald you liked it bend triing to use that pic for some time. Just seems it bring a smile to my face everytime me thinks of it.
John in CR
100 TW
No need for comedy Zip.... We've got 2 people trying to say a gearbox "adds power". A gearbox adds parasitic losses in the drivetrain as it's only effect on power. A change of gear affects torque and rpm of the wheel in an inverse relationship leaving power output unchanged.
h0tr0d,
Since you're insistent enough to talk down to others on the matter, then the best way to settle it is with a race.
h0tr0d,
Since you're insistent enough to talk down to others on the matter, then the best way to settle it is with a race.
h0tr0d
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John in CR said:h0tr0d,
Since you're insistent enough to talk down to others on the matter, then the best way to settle it is with a race.
Are talking about gears or nutrition?
Either subject, it wasn't my intention to talk down to anyone.
Regarding gears, I think they'll be a very important part of the EV revolution, that's why I trying that all at least try a geared system.
I love intelligent debates, where people present facts not gut feelings or bro science. We need guys like you for proper debate.
Regarding nutrition and health, the EV revolution needs guys like Luke to be strong and healthy. Since large belly circumference is linked to heart disease, diabetes, autoimmune diseases and cancer, I advise all to follow the paleo/primal lifestyle.
Race? Against my future 20kW bike? What did you had in mind?
Thanks JCR