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[briogio]

Just curious what you guys think, I'm putting it, or them, in Ducati Monster chassis and so far dual Agni's seems to be the way to go ...

[Bogan]

you should be able to do 100mph with just the one motor, keep the weight down and keep it simple. Certainly some of the really high powered ones run a single motor. Maybe go to AC tech as it seems a lot of the higher power bikes are running them. But I am not sure if the off the shelf AC stacks up to off the shelf DC currently.

[briogio]

you should be able to do 100mph with just the one motor, keep the weight down and keep it simple. Certainly some of the really high powered ones run a single motor. Maybe go to AC tech as it seems a lot of the higher power bikes are running them. But I am not sure if the off the shelf AC stacks up to off the shelf DC currently.

Thanks for the reply, but I don't know what you mean by you're "not sure if the off the shelf AC stacks up to off the shelf DC currently"?

[Bogan]

I can't recall any AC motor/controller combos you can buy that offer the same power/weight as DC, it may be the high powered ones are custom jobs. But I haven't had a very good look, so post up if you find any as I'd be interested in what is available too.

From your original post I'm guessing the cost isn't too much of an issue? considering a monster and dual agnis isn't a low budget operation!

[Biff]

My Ninja 250 does about 100mph and the spec sheet says the (internal combustion) engine is 27kW

With some aerodynamics and other tweaks I would bet that you can get 100mph with 20kW peak motor, maybe 15kW, but I think that would be really pushing your luck.  Has anyone here gone 100mph with a 15kW motor?

There are a bunch of DC motors out there that can get  you that performance, the Agni, the Mars Me0709, the Perm132 are probably the most common.

To go to AC, there is one I haven't heard mentioned much, that is the green Motorsports 18kW AC motor.  I don't know anything about it besides what is on their website
http://www.greenmotorsport.com/green_motorsport/products_and_services/3,1,388,17,12958.html

I imagine that could get you to 100mph quite nicely and it is just a bit heaver than the DC motors I mentioned.

-ryan

[briogio]

To go to AC, there is one I haven't heard mentioned much, that is the green Motorsports 18kW AC motor.  I don't know anything about it besides what is on their website
http://www.greenmotorsport.com/green_motorsport/products_and_services/3,1,388,17,12958.html

I imagine that could get you to 100mph quite nicely and it is just a bit heaver than the DC motors I mentioned.

-ryan
[/quote]
Thanks a lot for that!, I did see that motor last year but I forgot all about it. I really like the idea of a sealed, water cooled motor, especially in a motorcycle. It's nice and compact too with all the matched bits in one kit. I don't really understand the difference in characteristics between AC and DC motors though, what are they?

[Biff]

Thanks a lot for that!, I did see that motor last year but I forgot all about it. I really like the idea of a sealed, water cooled motor, especially in a motorcycle. It's nice and compact too with all the matched bits in one kit. I don't really understand the difference in characteristics between AC and DC motors though, what are they?

As far as the rider is concerned, there aren't any differences.  They both produce full toruqe at low speed, and produce that full torque for quite a while.  AC Induction motors don't have Permanent Magnets, so you can run them a little hotter.  Most magnets these days don't want to see over around 130 - 150C, where as the insulation of the wires is the temperature limiting device on an AC induction motor, so that is around 200C.  With that increase in temperature it makes it easer to transfer heat out.  For weight, a well designed PM motor will be lighter than a well designed Induciton motor.  The rotor on an induction motor will be slightly heaver than that of a PM machine, so that could affect handeling of the motorbike a bit I guess. The controllers are essentially the same for a PM brushless motor and an AC Induction motor, they just need slightly different feedback.  A PM motor needs position feedback and an induction motor needs rotor speed feedback.  DC brushed motors have simpler controllers, but the control of those motors is limited through the commutator which limits the top speed and power of brushed motors.

-ryan

[Bogan]

that does look like a very good option 27.5kW for 5 mins, with good cooling i wouldn't be surprised if you could run it at that continuous. Weight is pretty good too I reckon, 15kg, very competitive with DC for power/weight.

[briogio]

Thanks a lot for that!, I did see that motor last year but I forgot all about it. I really like the idea of a sealed, water cooled motor, especially in a motorcycle. It's nice and compact too with all the matched bits in one kit. I don't really understand the difference in characteristics between AC and DC motors though, what are they?

As far as the rider is concerned, there aren't any differences.  They both produce full toruqe at low speed, and produce that full torque for quite a while.  AC Induction motors don't have Permanent Magnets, so you can run them a little hotter.  Most magnets these days don't want to see over around 130 - 150C, where as the insulation of the wires is the temperature limiting device on an AC induction motor, so that is around 200C.  With that increase in temperature it makes it easer to transfer heat out.  For weight, a well designed PM motor will be lighter than a well designed Induciton motor.  The rotor on an induction motor will be slightly heaver than that of a PM machine, so that could affect handeling of the motorbike a bit I guess. The controllers are essentially the same for a PM brushless motor and an AC Induction motor, they just need slightly different feedback.  A PM motor needs position feedback and an induction motor needs rotor speed feedback.  DC brushed motors have simpler controllers, but the control of those motors is limited through the commutator which limits the top speed and power of brushed motors.

 I like the fact that the Green Motorsport AC motor is water cooled, that makes sense to keep temperatures in a specific range, and it's sealed from the elements unlike Agni's etc., also it's more compact/smaller. Does 3 phase work like 3 gears? Yeah the weight does seem competitive, I'm definitely leaning towards the GM motor.

[Bogan]

3 phase industrial motors can be wound in either star or delta configurations which act like different gears. So it is possible that the swap could be done on-the-fly to get two different 'gears'. Never heard of it being done though.