Espritmodel.com Telemetry Radio
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Old Oct 21, 2012, 09:17 PM
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Here is the data from the speed controller when both the motor and the esc puffed a little smoke...
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Old Oct 22, 2012, 03:13 AM
A-4 nut!!
skyhawk's Avatar
Vancouver B.C.
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I think your current line says it all.

Off hand - my first guess is the motor went and then it took the esc with it.

I have a place in Cloverdale that is a paved street that is empty with a big empty field. I live in Langley - so I'm pretty close to you
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Old Oct 22, 2012, 01:49 PM
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Quote:
Originally Posted by skyhawk View Post
I think your current line says it all.

Off hand - my first guess is the motor went and then it took the esc with it.

I have a place in Cloverdale that is a paved street that is empty with a big empty field. I live in Langley - so I'm pretty close to you
Yes I couldn't agree more, it definitely was the current that did the damage. At a certain point the current skyrocketed and did the motor in and eventually the esc...
But why? This motor and fan was mounted and balanced by edfhobbies after Jack had replaced all this for me the first time it burned up.
I was looking closely at the fan rotor when the clicking was happening and it didn't appear to be rubbing or binding on anything. Yet once I pulled out the unit and examined it closer I noticed a grooved cut into the shroud by the rotor and yet there is clearance between the rotor and shroud. Hmmm, then it dawned on me. I am suspecting the fibreglass intake duct that the fan fits into, being as tight and snug as it is, is actually squeezing the shroud hard enough to make the WeMo shroud press against the rotor. It isn't very rigid at all and having it in my hand I can see how much pressure is needed to make this happen. Despite all the times I ran the fans installed in the Raptor without issue this still seemed to happen now on the runway.

Either way, this is going to set me back again. I have to replace the fan, motor and esc this time. Furthermore I don't trust myself to install them into the jet anymore and to have this happen again. (more like I can no longer afford to repeat failures) CC has a great warranty and exchange program on their esc's but the fan and motor I am probably out of pocket for. I also need to re-evaulate the nose gear oversteer issue and I really should find a way to shed a pound of weight on this plane. This might call for a complete overhaul and guidance from someone who really knows how to build these.
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Old Oct 22, 2012, 03:07 PM
A-4 nut!!
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How bad is the fan? if it's a light rub - it should be no problem.

However - didn't you have this same thing before?

I hate to say it - but I think your problem is the cheap chinese motors. They are shorting or overheating (or vise versa) and it ends up taking out the esc as well. I've never really been one to cheap on stuff - but to go high quality, name brand all the way. No bucks.....no Buck Rogers!

As for your oversteer - if I'm understanding your problem correctly - just add in some Expo to the rudder channel. Hang in there - you'll get it.
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Old Oct 22, 2012, 04:13 PM
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Did the fan shrouds motor tube melt and distort again? May explain the rub. Also IMHO,2950kv is too high of a Kv for 6s in a minifan. You are pushing your set up using 6s with that motor. That motor is better suited to 5s in your application. Have to agree with skyhawk on the high quality/name brand components.

Looking at your castle data logs I see you need to change the motor pole count to 4 pole for your motor. Those rpm readings are wrong.
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Old Oct 22, 2012, 08:20 PM
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Im really thinking of just using 5s packs for this setup, I assume I wouldn't have to change anything? The shroud did not distort this time and the rotor looks ok but it doesn't look center to the shroud. Seems to be more clearance on the other side.

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I had used some duct seal putty when I mounted the fan. I thought it did a really good job of sealing and is easily removable but it is possibly squeezing the shroud a bit causing the rotor to drag?

As for the nose gear I think I might have too much expo I didn't get to adjust this at the time and I really should have.
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Old Oct 22, 2012, 08:29 PM
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Is this a cheap chinese motor? I really don't know for sure but I took these as highly recommended. I was told these work well on 6s for the WeMo fan but maybe they are safer on 5s?

http://edfhobbies.com/index.php?rout...product_id=176
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Old Oct 22, 2012, 08:35 PM
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What about the possibility of the thrust pulling on the esc and motor leads while i operation? Perhaps this could cause an internal short or maybe pull the motor to one side or the other rubbing out the rotor?
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Old Oct 22, 2012, 10:20 PM
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Quote:
Originally Posted by 172AMD View Post

Looking at your castle data logs I see you need to change the motor pole count to 4 pole for your motor. Those rpm readings are wrong.
Thanks, I just figured out how to change it now.
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Old Oct 22, 2012, 10:50 PM
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Quote:
What about the possibility of the thrust pulling on the esc and motor leads while i operation? Perhaps this could cause an internal short or maybe pull the motor to one side or the other rubbing out the rotor?
No.

However - the blades can stretch ever so slightly - if your not centered - it can rub, but a little rub is not a huge deal. If it does not center, wrap some aluminum foil tape around the motor untill it centers and takes up the space between the motor and housing.

I suspect as well the motors may not be suitable for 6S
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Old Oct 23, 2012, 07:12 AM
it wasn't me flying that plane
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United States, NC, Wilmington
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Whalley,
That motor is an excellent brand.....(velocity)
It has been proven to be great on 6s but is a hot choice for 6s..
Running this on 6 cells you need the very best batteries you can afford..(65c all the way)
It would be much milder on the components on 5 cells..rpm,s should be around the 59000 to 62000 area..
I have also burned one of these motors up (2900)but would not hesitate to purchase more as they are strong and well proven..def needs a heatsink...
Good luck,hope you get em squared away...........Chris
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Old Oct 23, 2012, 07:42 AM
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Quote:
Originally Posted by Hover or die View Post
Whalley,
That motor is an excellent brand.....(velocity)
It has been proven to be great on 6s but is a hot choice for 6s..
Running this on 6 cells you need the very best batteries you can afford..(65c all the way)
It would be much milder on the components on 5 cells..rpm,s should be around the 59000 to 62000 area..
I have also burned one of these motors up (2900)but would not hesitate to purchase more as they are strong and well proven..def needs a heatsink...
Good luck,hope you get em squared away...........Chris
Thanks for the reassurance. I am going to use them on 5s now. I am working with Jack at edfhobbies on getting a deal on replacement parts.

I am still trying to wrap my head around this and determine exactly what the failure was...
One of the two 6s packs was also damaged, either before the motor or as a result of the motor/esc failure. Now only works as 5s. Would a sudden loss of a cell cause a disruption with the esc and burn up the esc?
At the last moments the data log reads that 200A was flowing through the esc at time of death.
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Old Oct 23, 2012, 09:33 AM
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Currently I have two separate sets of battery leads coming to the motors from the battery packs. This is 10 awg silicone wiring with two capacitor packs on each one to cope with the length. This is making a total of 4 ft of wiring. I am using 5.5mm connectors on either ends.
In order to reduce weight I would like to know if can eliminate one of the sets of wiring and have both speed controllers wired in parallel? I would be still be using 2 cap packs instead of 4 and 2 ft of 10 awg instead of 4 ft. Instead of using two 6s lipo packs I would look into squeezing a single 5s pack into place.
I wonder what the load be like on 5s?
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Old Oct 23, 2012, 12:13 PM
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Really doubt it's the motor

This is the EDF Hobbies 2950kv motor pretty much eating a ton of power....

3000 watts, 7lbs of thrust out of a 70mm fan...eflux off the charts...2950kv motor windings could care less

At the end of the vid I thought the motor was reading 90F and then when I saw 90c I was like...got to cut it off and that was too late...the motor wasn't properly heat sunk either....just hooked up the wrong pack .

CS 10 blade rotor, EDFHobbies 2950kv motor, 6s, 3000watts 7lbs of thrust (2 min 17 sec)
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Old Oct 23, 2012, 12:48 PM
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Are you using one pack or 2?

Regards
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