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Triple Rewind of Unite 500W Motor
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duivendyk
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That's just silly,good cyclists manage about 20-25 mph by themselves,so this 'boost' of 250W max would only come into play,when accellerating or climbing it seems to me.
safe
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Europe and Australia are 250 watts.
Canada is 500 watts.
America is 750 watts.
...but this is on top of the pedal power. Pedal power is for a professional cyclist about 400 watts for a few hours. So even 250 watts added on top of the cycling power is a lot of extra power to have.
The human powered speed record is 82.33 mph and that's done with about 750 watts of human only power for a short distance.
So somewhere in that mix of regulations and performance possibilities there will emerge a racing organization that satisfies people's need for speed while still making the machines ebikes and not emotorcycles.
That's why too much of an emphasis on increasing power is a waste of time. The rules are bound to cap as a limit some power level. The goal should be to "tune" your motor so that it achieves the target power level while also being as efficient as possible. (and be able to do it without exotic batteries or controllers) The idea of a racing class for ebikes should revolve around a basic bike design that is inexpensive to make otherwise people will be slow to enter the sport. That's why I'm trying to build something that is low tech and yet performs well so that it can be sold cheaply for a mass audience of people. Most people will buy one of these "electric bicycle road racers" and just ride around town with them, but a few will trick them out and go racing with them. At least that's the concept I'm working towards...
Canada is 500 watts.
America is 750 watts.
...but this is on top of the pedal power. Pedal power is for a professional cyclist about 400 watts for a few hours. So even 250 watts added on top of the cycling power is a lot of extra power to have.
The human powered speed record is 82.33 mph and that's done with about 750 watts of human only power for a short distance.
So somewhere in that mix of regulations and performance possibilities there will emerge a racing organization that satisfies people's need for speed while still making the machines ebikes and not emotorcycles.
That's why too much of an emphasis on increasing power is a waste of time. The rules are bound to cap as a limit some power level. The goal should be to "tune" your motor so that it achieves the target power level while also being as efficient as possible. (and be able to do it without exotic batteries or controllers) The idea of a racing class for ebikes should revolve around a basic bike design that is inexpensive to make otherwise people will be slow to enter the sport. That's why I'm trying to build something that is low tech and yet performs well so that it can be sold cheaply for a mass audience of people. Most people will buy one of these "electric bicycle road racers" and just ride around town with them, but a few will trick them out and go racing with them. At least that's the concept I'm working towards...
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duivendyk
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What about this 15 km assistance limit?
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Fuzzo
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First to 20km could be interesting. A wattage limit makes sense. My bet is that the winner will be riding a bike that cost more than my actual motorbike, and they will be a very strong cyclist.
A speed limit under electric only would make no sense at all in a race, unless it is in hilly terrain. The entire race would be spent over that limit, under human power, and that would be best done on a bike carrying no extra weight (including battery-motor).
As for which set of laws makes the most sense, it's hard to say. Speed limits and wattage limits can be fiddled to come to much the same thing. Unless the speed limit was calculated on the ACTUAL rider's weight and typical load, rather than an 'average person'. Probably speed limit actually makes more sense from a legislative point of view, since it's easy to measure, and goes to actual safety. Wattage is a bit more nebulous - with the right gearing you can go pretty ****ed fast.
My own bike has the motor on a separate chain straight to the axle, so it stops contributing at a certain rpm, usually around 25 kmh. But it's easy to see that if it was going through my gearing system then I'd have a lot more control and would be able to get a higher top speed (and better power low down on hills too). About the only advantage to this configuration from my point of view is that gear changes are very smooth because the motor is still powering the wheels, so I can slack off the pedals during the shift without losing the motor's contribution.
A speed limit under electric only would make no sense at all in a race, unless it is in hilly terrain. The entire race would be spent over that limit, under human power, and that would be best done on a bike carrying no extra weight (including battery-motor).
As for which set of laws makes the most sense, it's hard to say. Speed limits and wattage limits can be fiddled to come to much the same thing. Unless the speed limit was calculated on the ACTUAL rider's weight and typical load, rather than an 'average person'. Probably speed limit actually makes more sense from a legislative point of view, since it's easy to measure, and goes to actual safety. Wattage is a bit more nebulous - with the right gearing you can go pretty ****ed fast.
My own bike has the motor on a separate chain straight to the axle, so it stops contributing at a certain rpm, usually around 25 kmh. But it's easy to see that if it was going through my gearing system then I'd have a lot more control and would be able to get a higher top speed (and better power low down on hills too). About the only advantage to this configuration from my point of view is that gear changes are very smooth because the motor is still powering the wheels, so I can slack off the pedals during the shift without losing the motor's contribution.
safe
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Good question.
Some of these motors have holes drilled into the brush mounting metal sleeves and what you do is insert the brush and compress it inside the sleeve, then push a thin wire into the hole so that it will block the brush from springing back out. You then assemble the motor and at the last minute before closing things up you pull out those thin wires and the brushes drop down to where they are supposed to be.
Now on the 500 watt Unite motor I've been rebuilding it's a little different...
For these motors you need to pry back the spring and wrap it back onto the outside of the metal sleeve until you find some spot with enough friction to have it be able to hold itself in place on it's own based just on friction. If necessary you can scratch the outside of the metal sleeve someplace so that the spring grips enough to keep it from dropping back down in and forcing the brushes out. Anyway... if you manage to get all four springs to get hung up outside the sleeve you can then assemble the motor and at the last minute reach a screwdriver inside and pop the springs back into their metal sleeves.
I know... it all sounds very crude...
One last trick is that you can insert the iron core / commutator / brushes inside the shell AFTER you get the brushes all installed. How I do this (and it's a scary part of the assembly process) is I insert my hand inside the shell (where the magnets are) and gently lower the shell onto the iron core / commutator assembly. There is a point where the magnetic attraction SUDDENLY attracts the two parts together so be ready for that... but the nice thing about doing things this way is that you can inspect the brushes to be sure they are perfect before you get to this final assembly phase. Stand over the top of the shell and drop it down onto the core while it sits on the ground... you need the core to be on the ground and your hand needs to strongly be pressing it so that when the magnetism attracts it doesn't jump at you.
Just be careful with your fingers, be sure to have your fingers inside the core or you are going to get a painful pinch.
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safe
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Power Limit Debate
We are in the pioneering days of ebike racing and things are still evolving.
My strategy has been to build a bike that would be able to be "detuned" so that when it was sold it would satisfy the American laws for ebikes:
Must have operable pedals.
750 watts output.
Maximum speed (as geared) 20 mph.
...the "no brainer" way to get around the law is to sell the bike with a comically low gear with a one speed transmission. The buyer then gets the bike home and adds a multispeed transmission (derailler or a multispeed hub) and they then expand their performance significantly.
The law is designed to allow the manufacturer to sell things legally. Enforcement after that is up to the local police. When it comes to the racetrack the police are absent, so the speed limits are off, but the motor itself has a limit that I personally think should be maintained.
My idea is to have a 1000 watt (input) limiting circuit that is able to automatically multiply together the voltage and the amps that are being delivered. This way you get a PRECISE power level no matter if it's a 24, 48 or 72 volt system. The circuit would deliver less amps if you had more voltage. Also, as the battery drains it will tend to voltage "sag" and this circuit would compensate for that and so the power level would be the same on lap one as it would be on the final lap.
The idea I'm copying is the "restrictor plate" concept... restrict the power entering the motor and then it's up to the motor designers to tune that as close to perfection as possible.
This is where rewinding is going to be important... in order to optimize the 1000 watt allowed input you would want to as perfectly as possible match your equipment to that limit.
...I'm already thinking way ahead on this stuff. (so rewinding is an advanced trick for a sport that doesn't yet exist and for a bike I haven't even completed yet
)
My guess would be that the brushless motors would eventually dominate over the brushed. However, there is another motor type that I can envision as being dominate (if perfected) which is the "Switched Reluctance" motor that behaves as an induction motor. That would permit a much wider powerband. But that's stuff that is waaaaaaay down the road. For now the permanent magnet motor is the only way to go and brushed is cheaper (and less complicated) than the brushless.
As the saying goes:
"Keep It Simple Stupid." (KISS)
...for now the goal is low tech and high performance. (get the best out of the cheaper technology)
We are in the pioneering days of ebike racing and things are still evolving.
My strategy has been to build a bike that would be able to be "detuned" so that when it was sold it would satisfy the American laws for ebikes:
Must have operable pedals.
750 watts output.
Maximum speed (as geared) 20 mph.
...the "no brainer" way to get around the law is to sell the bike with a comically low gear with a one speed transmission. The buyer then gets the bike home and adds a multispeed transmission (derailler or a multispeed hub) and they then expand their performance significantly.
The law is designed to allow the manufacturer to sell things legally. Enforcement after that is up to the local police. When it comes to the racetrack the police are absent, so the speed limits are off, but the motor itself has a limit that I personally think should be maintained.
My idea is to have a 1000 watt (input) limiting circuit that is able to automatically multiply together the voltage and the amps that are being delivered. This way you get a PRECISE power level no matter if it's a 24, 48 or 72 volt system. The circuit would deliver less amps if you had more voltage. Also, as the battery drains it will tend to voltage "sag" and this circuit would compensate for that and so the power level would be the same on lap one as it would be on the final lap.
The idea I'm copying is the "restrictor plate" concept... restrict the power entering the motor and then it's up to the motor designers to tune that as close to perfection as possible.
This is where rewinding is going to be important... in order to optimize the 1000 watt allowed input you would want to as perfectly as possible match your equipment to that limit.
...I'm already thinking way ahead on this stuff. (so rewinding is an advanced trick for a sport that doesn't yet exist and for a bike I haven't even completed yet
)My guess would be that the brushless motors would eventually dominate over the brushed. However, there is another motor type that I can envision as being dominate (if perfected) which is the "Switched Reluctance" motor that behaves as an induction motor. That would permit a much wider powerband. But that's stuff that is waaaaaaay down the road. For now the permanent magnet motor is the only way to go and brushed is cheaper (and less complicated) than the brushless.
As the saying goes:
"Keep It Simple Stupid." (KISS)
...for now the goal is low tech and high performance. (get the best out of the cheaper technology)
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duivendyk
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The only sensible approach is to allow each rider a certain energy supply per race and no other restrictions.Do what you want with it.Then it would be a test of both rider & technology,which is what this ought to be about, as far as I'm concerned
Ok thanks Safe, I just put two together now which is why I posted the Q, I ended up using sticky tape to the side of the sleeve depressed the brush brought the tape over the front of the brush to hold it depressed then taped down to the outside of the cap, four times, slotted the commutator/armature in and removed the tape, walah! The same as you said after that, drop the magnet shell over the armature being careful and slow. I wonder how they do it at the factory tho, there must be a faster way, maybe like you said the pins etc.
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