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PostPosted: Mon Jun 09, 2014 6:28 am 
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I just started using the evolve motor on my TI.
When the motor is off (but in the mirage well) the propeller sometimes freely rotates.
Sounds like it is on.
Is this ok?


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PostPosted: Mon Jun 09, 2014 12:43 pm 
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I have no experience with the Evolve system, but I've been playing with electric powered high performance R/C airplanes for a very long time ...

... and from that experience I would think you would want it to "freewheel" as A) it provides less ressistance whilst sailing/pedaling and B) If the Evolve system were to apply a braking algorithim it would require electircal power to stop it from spinning thereby using your available power when you don't want to.

What would be neat would be if it was regenerative - I.E., that spinning while powered off was to charge the battery. Unfortunately, propellors are designed and optimized for propulsion in one direction and are several orders of magnitude less efficient in the other direction. Also, the motor controller would need to be engineered for this - perhaps it is :?:

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PostPosted: Mon Jun 09, 2014 1:35 pm 
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emsmag, good question; I also wondered why this is if I became aware of the noise the first time. But then I came up with the same thinking as PassWind posted. You can stop the rotating by putting in the alignment tool, but only if there will be a risk of damage if the propellor rotates unnecessarily over a long time. Would that be the case?


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PostPosted: Mon Jun 09, 2014 3:10 pm 
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Fyi... Using on an Island while sailing? Not recommended to leave the drive in as it does cause significant drag... and I assume wear on the motor if forced to spin while sailing.

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PostPosted: Mon Jun 09, 2014 3:29 pm 
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If the motor is a permanent magnet motor (which I assume it is). If your spinning the motor it generates electricity which would be pounding the diodes in the PWM drive with back current that's not supposed to be there. I'm just sayin.


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PostPosted: Mon Jun 09, 2014 8:10 pm 
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The reason for leaving the motor in is pure laziness. We were returning from using the evolve to explore a narrow canal (with sail furled) and then sailing out into the open bay w/10-15 kt winds.
So its a big pain to turn around and help my wife take out the motor, secure and stow it and plug the mirage well with the cassette. Then I might have to put the motor back in to return home if the winds don't cooperate.
I also like the idea of occasional power assisted tacking.
I tend to agree that freewheeling will cause additional wear on the prop and gears. But how much wear is that when compared to powered usage? It also does seem better to allow the prop to freewheel rather than locking it in place. Like leaving your car in drive going uphill. I wish there were a clutch mechanism that disengaged the gears and put it into a true neutral position. I think that if it were like an airplane prop you could feather the propeller to stop it from rotating. Correct?
Passwind - is your rc experience the same with both electric and gas motors?
The freewheeling only occurs going upwind - but I'm sure tidal current plays into it.
I did get it to stop by momentarily reversing the throttle slightly - but that is something that would surely fry the motor or controller if done for any length of time.
I do love that motor.


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PostPosted: Mon Jun 09, 2014 10:22 pm 
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I used to work for a company that made high performance DC servo motors and have lots of experience designing and building them. Chances are the motor is direct drive, so if you leave it in the water with no power it will simply freewheel and not hurt anything. However the drag will slow you down slightly. Yes I said you would be pounding the diodes a little in the pwm controller which will cause some heating on the diodes on the drive but it would have to be sustained high rpm for quite a while to do any damage, probabably nothing you need to worry about unless you are being towed by a powerboat. If it inconvenient to pull the drive out for short periods of time between use and you just let it freewheel I can't imagine your going to hurt anything. I definitely would not try to block the prop or attempt to hold the motor in reverse (that would be bad). Personally I wouldn't worry about it.


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PostPosted: Tue Jun 10, 2014 9:00 am 
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emsmag wrote:
The reason for leaving the motor in is pure laziness. We were returning from using the evolve to explore a narrow canal (with sail furled) and then sailing out into the open bay w/10-15 kt winds.
So its a big pain to turn around and help my wife take out the motor, secure and stow it and plug the mirage well with the cassette. Then I might have to put the motor back in to return home if the winds don't cooperate.
I also like the idea of occasional power assisted tacking.
I tend to agree that freewheeling will cause additional wear on the prop and gears. But how much wear is that when compared to powered usage? It also does seem better to allow the prop to freewheel rather than locking it in place. Like leaving your car in drive going uphill. I wish there were a clutch mechanism that disengaged the gears and put it into a true neutral position. I think that if it were like an airplane prop you could feather the propeller to stop it from rotating. Correct?
Passwind - is your rc experience the same with both electric and gas motors?
The freewheeling only occurs going upwind - but I'm sure tidal current plays into it.
I did get it to stop by momentarily reversing the throttle slightly - but that is something that would surely fry the motor or controller if done for any length of time.
I do love that motor.


err laziness no. motor sailing and tacking single handed yes. yes it is difficult to take the evolve out when you are going along and the wind picks up.
so what do you do stop and start again?
No

CC

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PostPosted: Tue Jun 10, 2014 10:15 am 
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... because Im a techno-weeny at heart I called Torqeedo USA and asked

1) The motor is a brushless design (meaning it is a 3 phase AC design)

2) it IS in fact geared

3) They DO recommend it be removed when the boat is moving and the unit is not providing propulsion

4) it is NOT regenerative and by not removing it does create waste heat as well as gear train stress

5) it will "freewheel" and is not "braked" by the motor

The person I talked with was not terribly technical but did know the answers to my questions - I did not want to push further

If anyone wants further info their contact info is

Torqeedo Inc.
171 Erick Street, Unit A - 1
Crystal Lake, IL 60014
USA
T +1 815 444 8806
F +1 815 444 8807
usa@torqeedo.com

mmiller wrote:
... and I assume wear on the motor if forced to spin while sailing.


Motor, not so much as the only wear item on a brushless motor would be the bearings. Geartrain ? perhaps .. but if they are using a planetary system I doubt much.

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PostPosted: Tue Jun 10, 2014 11:03 am 
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Many thanks for your call and all the advices!


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PostPosted: Tue Jun 10, 2014 10:41 pm 
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@passwind Thanks, great info!





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PostPosted: Tue Jun 10, 2014 11:13 pm 
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Having the same "problem". I use the motor when I need it (no wind, going against the wind etc) and in order to save battery power turn it off when the wind is good and no additional motor power is needed.

When sailing fast and the motor is plugged in the mirage drive the propeller rotates by the speed of the boat. I read in one of the torqueedo manuals that this is no good...so I just plug in the "metal bar" to stop the rotating propeller and sail the TI without motor power.

This works pretty well and I did not notice a significant drag sailing the TI with the (not running) motor in the mirage drive slot.

Am pretty sure it indeed will cause major drag if you sail fast and "on the limit" but I am mostly out for fishing (trolling) and try to maintain a rather low speed of 3-4 knots.

Peace
Serbi


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PostPosted: Wed Jun 11, 2014 12:50 am 
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Oh if only that rotating propeller could be used to charge the battery! 8)


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PostPosted: Tue Jul 08, 2014 8:38 pm 
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I was thinking of one of these for next season but now I am not so sure. From what I am reading, I would insert the motor in the drive, use it until there is wind, then once sailing under wind power remove the motor so I don't cause extra stress on it? seems like a pain, and makes one of the systems more attractive, where you custom mount a trolling motor.

I would have to stow the motor, then if I lose wind, retrieve the motor and insert it again. lots of work...


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PostPosted: Tue Jul 08, 2014 9:56 pm 
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That is one of the reasons I went with an Ultralight 403 instead of an eVolve - very quick-n-easy in water/out of water. It's not on in this pic, but there is a rope attached to the top of the "fin" with a bungee hook on the other end that hooks into the carry handle to lift motor out of water.

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