Oh, and if multi-speed was valuable, then a lot of boats in the marina have two-speed trannies.
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Jason, I'm not saying they don't exist in vehicles, but let's face it, for boats, they are less than rare. You are talking about <1% of boats on the water. Go to any marina and almost all, if not all, of the ICE powered vessels will be coupled from ICE to the prop via a straight shaft. If there is a transmission, it is only for F/N/R.
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Jason, Your sun gear idea is certainly novel. And, I think its drawbacks would override any benefits. For instance, if this is so good, then why don't we see ICE engines attached to one? And, you'd need a heavy gearcase filled with oil. Plus, electric motors can be quickly reversed. Finally, most electric motors can exceed their nameplate speed for some amount of time.
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Jason, Your sun gear idea is certainly novel. And, I think its drawbacks would override any benefits. For instance, if this is so good, then why don't we see ICE engines attached to one? And, you'd need a heavy gearcase filled with oil. Plus, electric motors can be quickly reversed. Finally, most electric motors can exceed their nameplate speed for some amount of time.
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Agreed that it isn't needed. And doubly so since prime movers for boats tend to operate in a narrower speed range than road vehicles. My proof? If variable gearing was an advantage, you'd see ICE powerboats with 2-or 3-speed transmissions.
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Was just gonna say!
With the right gearing/belt drive there is no need for torque multiplication.
An electric motor will give you the flattest torque curve.Basically max torque from 0 rpm, all the way to max rpm.The cvt allowes the motor the rev out to max. torque and stay there.No rpm change of motor but varying prop speed.With electric you don't need to do that!mattelderca
On Sunday, March 2, 2014 3:06:02 PM, Robert Lemke <robert-lemke@att.net> wrote:
With all the torque available at any RPM for an electric motor, unlike a ICE, a continuously variable transmission just isn't needed.Bob
From: "wewhite74@gmail.com" <wewhite74@gmail.com>
To: electricboats@yahoogroups.com
Sent: Sunday, March 2, 2014 10:49 AM
Subject: [Electric Boats] CVT Transmission
has anyone thought of using a CVT for propulsion?It would be interesting to hear the potential benefits and disadvantages from some of our more experienced members
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