Damon,
Thanks for the info.
Where do I find this mystical motor magician Jim Husted?
I've been wondering about the freewheel myself. I've done quite a bit
of research on them though, so I may just get one anyway. They are,
from my experience, not available for 1" shafts without going to really
bulky high torque couplings. My drive shaft is 1" and the largest size
in the smallest coupling unit I've found is .750". Given the DC motor
will only put out half the original power of the ICE, I might just turn
the end of the shaft down to 3/4" to accommodate the coupling. I have a
spare shaft to try it out with.
The plan all along has been 72v, if not more. I'm just having a hard
time fitting batteries on the bike. I'm considering the "battery saddle
mount" approach, but was hoping to contain them all within the frame.
Seth
Date: Mon, 06 Aug 2007 16:54:38 +0000
From: "damon henry" <[EMAIL PROTECTED]>
Subject: Re: [ElectricMotorcycles] More on motors
To: [email protected]
Cc: [EMAIL PROTECTED]
Message-ID: <[EMAIL PROTECTED]>
Content-Type: text/plain; format=flowed
I don't think that there is any general differences in the D&D and ADC
motors that are relavant to your application.
There are two main things to consider when comparing similar series wound
motors, and they both have to do with how much current they can handle. The
first is the brushes. Looking at the size of the brushes and the leads
gives you a good idea of how much current they are designed to handle, but
be aware that even in just the ADC 6.7 inch line theses are not always the
same. There are 4 and 8 brush ADCs. On my motorcycle I have a 4 brush ADC
and it handles my 400 amp controller just fine. The second thing to
consider is thermal mass. Basically the more copper you have in a motor the
more mass it has to handle the heat produced by higher currents. Again,
sticking with just the ADC 6.7 inch line of motors there are several
different armature lengths. The longer armatures have more wire wrapped
around them and weigh more meaning it takes them longer to heat up to the
point that you have problems. Again on my motorcycle I have one of the
shorter ADC 6.7 inch motors, althouh not the shortest, and it handles my
riding without ever overheating. In summary, when compairing two similar
series wound motors you are generally better off going with the one that has
the beefiest brushes, and weighs the most. I strongly recommed working with
Jim Husted. He has access to lots of motors in this size because they are
commonly used as lift pumps on forklifts. He can pick you up a core for a
couple of hundred bucks, then build it into something special for a couple
hundred more. In the end you will usually end up with a rebuilt motor that
is better than brand new because he will modify it to fit your application.
The price is usually less than a brand new one will cost you, plus you
will have Jim to bounce any questions off of and he sends every EV motor out
with a little of his Hi Torque fairy dust :-)
As far as the freewheel thingy, it sounds like a lot of effort and very
little reward. A series wound electric motor already freewheels very
nicely, so leaving everything connected works just fine. My motorcylce
rolls like crazy when I let off the throttle.
Finally, I strongly suggest going with 72 volts for any motorcycle you are
hoping to ride at freeway speeds. It can be done on less, but going with 72
volts makes it much easier to keep good acceleration and a high enough top
end. I'm running 54 volts with the stock 14 to 41 gear ratio. I have
decent acceleration and can just creep my way to 60 mph. With a higher
voltage controller I could change my gear ratio and have better
acceleration and a bit higher top end.
damon
From: "Seth A. Keel" <[EMAIL PROTECTED]>
Reply-To: ElectricMotorcycles <[email protected]>
To: [email protected]
Subject: [ElectricMotorcycles] More on motors
Date: Mon, 06 Aug 2007 04:00:53 -0500
Hello all,
Great list. I've been following along for about 3 months now and it's been
very helpful to hear the comments and ideas from the members. Travis' post
has got me going, 'cause I'm interested in motors too. There is a 1975
Honda Gold Wing disassembled in my basement and I'm trying to figure out
how to rebuild it. Which motor to get is the current question and it's
such a pivotal one that the rest of the design is waiting for it.
Here are a few questions that I'm struggling with.
1) What's the difference in quality between ADC and D&D?
2) Can a PMG-132 push my sled at 60mph for 10 minutes without overheating?
There's another 5 mi. of city driving on top of that to get to my job. Can
it be done on 60v or or should it be done with 72v?
3) What's a typical watt/mi estimate for a bike that's around 1000lbs. with
rider? I've been using 300watts/mi. in my calculations. Is that close?
4) Do any of you use an overrunning clutch coupling, or something similar,
so the motor shaft isn't directly linked to the final drive? An OCC is
basically a freewheel. My diesel has a mpg readout in dash which, even if
it's not perfectly accurate, definitely shows that disengaging the engine
when it's not needed and coasting to stops saves a lot of fuel. I'd like
to do the same with the EM without having to add a clutch. It would also
eliminate any concern over the motor lockup issue that was discussed
recently.
Any thoughts or suggestions would be very much appreciated. Thanks,
Seth
_________________________________________________________________
A new home for Mom, no cleanup required. All starts here.
http://www.reallivemoms.com?ocid=TXT_TAGHM&loc=us
