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EVcycle replied to the thread Adding a centrifugal clutch to the drag bike..
" DC motors seem to transfer the energy more quickly. That is why a lot of drag racers have been using them at the expense of the brushes, added weight and lower RPMs. I still have a DC motor in my street ridden Cafe racer.
The AC motor seems to need a bit more rotation before it gets rolling, but after that is is a torque monster up to 8000 RPM and the only issues (to me anyway) is a bit more cost and getting all the programming right in the controller.

The bike is running well with the Sevcon/AC motor, but that will be ungraded soon ( bigger motor and controller).

Like anything in the world of EVs, it depends on the application on what you want / need. "

8 Hours Ago

EVcycle clicked Likes for this post: Adding a centrifugal clutch to the drag bike. by Spoonman

8 Hours Ago

EVcycle clicked Likes for this post: Adding a centrifugal clutch to the drag bike. by Stevo

8 Hours Ago

EVcycle replied to the thread Stacking chargers (Just in case you wanted to know.).
"
Quote Originally Posted by Stevo View Post
Are you going to add your own reverse protection?
I was not planning on it. I am the one that made the error so I paid the price. The new ones have that. "

8 Hours Ago

EVcycle clicked Likes for this post: Stacking chargers (Just in case you wanted to know.) by Stevo

8 Hours Ago

Stevo replied to the thread California bans ICE cars and trucks by 2035 - but not bikes.
" Ya...dimwit politics as usual. As long as we keep voting these morons into office we'll keep getting more of the same.
But it's all good because we have an endless money supply

Stack Sats and chill my friends... the show is just starting "

10 Hours Ago

Richard230 replied to the thread California bans ICE cars and trucks by 2035 - but not bikes.
" I had the same observation regarding his announcement yesterday. But then I am not surprised. When was the last time that electric motorcycles were ever mentioned by a government official or legislator? BTW, by 2045 big-rig trucks are to be gas-free too. Another thing that wasn't mentioned in the announcement was a plan for updating the state's infrastructure so that it will be able to supply the power needed by all of these new electric vehicles. Apparently, just forcing people to purchase EVs though regulation will somehow overhaul our entire power transmission system so that the necessary electrical power can be distributed to electrical refueling stations that someone else will build. Likely not Big Oil, though. "

15 Hours Ago

MegaWatt replied to the thread 1970 Honda CT90 Electric Conversion.
" I finally received a reply from Buchanan Spoke & Wheel. They have a 1.4" wide 17" aluminum wheel, so the conversion is back on track. When I tear the bike down for the conversion, I'm going to send them the front hub to lace in a aluminum wheel so both match. "

18 Hours Ago

Spaceweasel created the thread California bans ICE cars and trucks by 2035 - but not bikes.
" Gov. Newsom just signed an executive order banning the sale of new ICE cars and light trucks after 2035.
https://www.gov.ca.gov/wp-content/up...79-20-text.pdf

Conspicuously absent from this is mention of electric motorcycles. Given the rapid advancement of battery tech I expect ev bikes will be plenty competitive on range/weight/power by then. I'm sort of surprised he didn't include them. "

1 Day Ago

Stevo clicked Likes for this post: Adding a centrifugal clutch to the drag bike. by Spoonman

1 Day Ago

Spoonman replied to the thread Adding a centrifugal clutch to the drag bike..
" Acceleration under gravity is certainly a constant.
Accordingly, velocity builds linearly to the point of aerodynamic significance.
Displacement is a second order function alright, but not either of the others.

With the bike, if we can assume full current from 0 RPM then, winding effects neglected, the torque will be a constant up to the point where the BEMF comes into play.
Consequently the acceleration must also be constant, and hence the velocity gain linear (to the point of aerodynamic significance).

To your arse it won't feel like that though. "

1 Day Ago

Stevo replied to the thread Adding a centrifugal clutch to the drag bike..
" Attachment 8509


Is Acceleration exponential at the start?
When you drop an object from a tall building, it takes an acceleration constant to reach max velocity, then the speed varies by wind drag, but the initial acceleration from a dead stop isn't linear. If you dropped a heavy Pb ball and a really light ball same size, they should still fall at the same velocity. But that is gravity, not emf.
Maybe your feeling that initial exponential acceleration in the seat of your pants! "

1 Day Ago

Stevo replied to the thread Stacking chargers (Just in case you wanted to know.).
" Are you going to add your own reverse protection? I used a solar panel diode between my 2 Mean Wells. I had one on both power supply's + outputs and probably not necessary as these MeanWells have reverse protection built into them. One of the diodes fried on the + to battery pack output after months of charges. They are rated for 50 amp. I havent had any more issues for months of charging now.
I was wondering how others are charging their packs. Thanks for sharing. "

1 Day Ago

Spoonman replied to the thread Adding a centrifugal clutch to the drag bike..
" oh my goodness that's pretty! "

1 Day Ago

EVcycle replied to the thread Adding a centrifugal clutch to the drag bike..
"
Quote Originally Posted by Spoonman View Post
When you say AC you're referring to PMAC not squirrel cage I expect yes?
Yes, A Motenergy 1507. "

1 Day Ago

Spoonman clicked Likes for this post: Adding a centrifugal clutch to the drag bike. by EVcycle

1 Day Ago

Spoonman replied to the thread Adding a centrifugal clutch to the drag bike..
" When you say AC you're referring to PMAC not squirrel cage I expect yes?

You've answered my question in any case - it sounds like there's a necessary lag until sufficient angular velocity is developed to really launch the thing (which makes perfect sense of course), so having something in there which permits you to have it spun up before you try and move certainly makes sense alright. "

1 Day Ago

EVcycle replied to the thread Adding a centrifugal clutch to the drag bike..
"
Quote Originally Posted by Spoonman View Post
How sure are you that this isn't more to do with how your controller is programmed than anything else?
If you're dealing with some sort of software limit on the ramping rate for current, then the flywheel dump may not help as much as you expect as the controller is still going to attempt to regulate the rate of change - granted if any such rate is RPM linked then it may not try quite so hard... but the point is that there are a substantial number of unknowns there.

Once the magnetic fields are established (for which I would expect there will be a larger time constant in the case of induction than PM), then the torque should be pretty much instant in any practical terms. Only reason for this not to be the case is if something is the control stages is trying to be too clever.
AC motors.....100% torque at zero RPM is still not moving HP. This is not always a bad thing as in Drag racing you do not want to "blow your tires off"

I have everything running at 100% in the controller (2 different controllers and motors) The start seems soft until I get to about 100 RPM or so.

I recently had an interesting chat with one of the leading AC motor manufacturers explaining my 100 RPM theory and was surprised to find out that the was the magic number to get things really rolling...100 RPM. The had proven it on a dyno.. (go figure)
Depending on your gearing, you may get to 100 RPM very quickly so it may not be noticed, but I have two vehicles with no transmission and am drag racing them to 100+ MPH in a 1/4 mile.

I still think a centrifugal clutch would help us with our ET.

Ed "

2 Days Ago

EVcycle clicked Likes for this post: Adding a centrifugal clutch to the drag bike. by Frank

2 Days Ago