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Old Jan 27, 2013, 01:30 PM
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Romania, BV, Brasov
Joined Apr 2010
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Hello,
I am surprised by these results. You got peak efficiency at speeds which seems for me too high for a 24N28P motor. I also wonder that you (and the manufacturer) recommend not so big propellers. Particularly, the last reviewed motor XM4010TE-7 is recomended to be used in the range of 10-16V with a propeller of up to 12x10.
Currently I am using the quite similar NX-4008 motor: http://hobbyking.com/hobbyking/store...ter_Motor.html, rewound by myself to have Kv=500rpm/V. (It can be compared to your last reviewed XM4010TE-7.)
The power supply is not 3-4s as recommended (for the original Kv=620rpm/V), but 2s and I use really big propellers: Aeronaut CAM 16x13 and even 18.5x15 (on Easy Glider). It performs very well and I fly usually 1h25' with 2s 3.3Ah.

Can you test one of them (let's say XM4010TE-7) at 2s to find out the peakeff for 2s? Or even for 6V? (because my rewound NX-4008 with Kv=500rpm/V supplied at 8V can be compared with XM4010TE-7 at 6V)
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Last edited by ViorelX; Jan 27, 2013 at 01:43 PM.
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Old Jan 27, 2013, 02:34 PM
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Fourdan's Avatar
Antony (France)
Joined Sep 2003
3,016 Posts
Hi ViorelX

XM4010TE-7 @ 6V
6,01 V ; no load Io = 0,86 A ; 3853 rpm ; Peakeff 78,4%
taking Rm = 0,0920 ohm

Using Dualsky Calc 3.20 on XM4010TE-7 (motor #56)
http://www.rcgroups.com/forums/showthread.php?t=1078160
On 2S you could go to APC 17x8E at limit 18A
But you are far away from Peakeff
You need also some cooling, because temperature is the major actor

On your rewound 4008 (Kv 500 rpm/V) what is your mesured ph-ph resistance ?
Louis
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Last edited by Fourdan; Jan 27, 2013 at 02:45 PM.
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Old Jan 27, 2013, 03:10 PM
Registered User
Romania, BV, Brasov
Joined Apr 2010
15 Posts
Hi Louis,
I got a ph-ph resistance of 85mOhms. If the motor is turned at about 3000rpm (with a lathe) a phase generate a 4.4V voltage and thus I determined a Kv of about 500rpm/V (actually, the lathe rpm may be of 2800rpm).
With the 16x13 propeller the static current consumption on full throttle is of 18A. After 1min of running the motor is still cold.
With the 18.5x15 propeller the motor takes 22A and warms up a bit after 1 min of run. It doesn't seem to me that it runs far away from the peak efficiency.
And, of course, I haven't had any problems with the heat inflight after long time running.
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Last edited by ViorelX; Jan 27, 2013 at 03:25 PM.
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Old Jan 27, 2013, 04:16 PM
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Antony (France)
Joined Sep 2003
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Hi ViorelX
Is your 4.4V peak (oscilloscope) or rms (AC DMM) ?
Louis
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Old Jan 28, 2013, 02:06 AM
Registered User
Romania, BV, Brasov
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Not peak, I measured the rms value by a digital multimeter.
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Old Apr 12, 2013, 09:52 AM
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Joined Mar 2013
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Neodymium grade

Great review, thank you.

What is the grade of neodymium? In for example XM5015TE-3.
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Old Apr 15, 2013, 06:04 AM
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Antony (France)
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Quote:
Originally Posted by Luxo View Post
Great review, thank you.

What is the grade of neodymium? In for example XM5015TE-3.
Hi
Hereunder is the reply coming from Dualsky HQ Shanghai after my asking:
The magnets for TE series are N42SH, the temperature grade is 150C
Louis
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Old Apr 15, 2013, 09:08 AM
Jack
USA, ME, Ellsworth
Joined May 2008
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And here, at K&J Magnetics, are a couple of pages that present some handy specs for the various grades of magnets:

Neodymium Magnet Physical Properties - http://www.kjmagnetics.com/specs.asp

Pull Force and Surface Field Data - http://www.kjmagnetics.com/magnetsummary.asp

I can't vouch for the honesty or accuracy of all the info but to those of us that know little, it seems more interesting than knowing less...

Jack
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Old May 29, 2013, 08:05 AM
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Joined Aug 2009
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Hi.. fourdan..

Nice motor.., i have question about :

1. Where to find Motorshaft for dualsky xm4995TE and bearing parts number ?

2. How about the bearing quality, especially life hours ?
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Old May 29, 2013, 08:11 AM
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Hi.. fourdan..

Nice motor.., i have question about :

1. Where to find Motorshaft for dualsky xm4995TE and bearing parts number ?

2. How about the bearing quality, especially life hours ?
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Old May 29, 2013, 02:14 PM
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Antony (France)
Joined Sep 2003
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Quote:
Originally Posted by wongtukul View Post
Hi.. fourdan..

Nice motor.., i have question about :

1. Where to find Motorshaft for dualsky xm4995TE and bearing parts number ?

2. How about the bearing quality, especially life hours ?
Hi
XM4995TE???
Maybe XM4005TE ?
The best is to ask directly to Dualsky or 2DogRC
I am not a vendor, just a tester and Dualsky Calc developer.
My XM4005TE is for now in my drawer in its box (after testings)
Louis
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Old May 29, 2013, 02:24 PM
Jack
USA, ME, Ellsworth
Joined May 2008
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Quote:
Originally Posted by wongtukul View Post
Hi.. fourdan..

Nice motor.., i have question about :

1. Where to find Motorshaft for dualsky xm4995TE and bearing parts number ?

2. How about the bearing quality, especially life hours ?
These are probably the bearing you want here on the Dualsky pages:

http://www.dualsky.com/pro_list_for....nid=128&id=733

But they tell you no sizes and finding a dealer that has them in stock is pretty unlikely. It is easiest way is to measure your bearings and just buy the right sized bearings

You want to measure the O.D. and thickness of your bearings (the shaft size is the I.D.). Those can be measured in the motor if you remove the magnet housing. The I.D. is the shaft size, that is 1/8" (0.125") which also happens to be exactly 3.175mm.

The bearings for 3.175mm/1/8" shafts are almlost always Imperial or Inch sized bearings and they cause a lot of confusion because people are always trying to get the measurements on them to come out in metric sizes. And they simply will not do that. Here is a list of the 0.125" I.D. bearings that are for sale at rcbearings.com, maybe you can find yours in the list:

http://www.rcbearings.com/search.php....125&x=56&y=10

When you get your new bearing they probably will not be lubricated, you can do that for yourself:

bearing lubrication - http://www.rcgroups.com/forums/showp...8&postcount=17

On the shaft, buy any 0.125" or 3.175mm shaft that is as long as you need or longer. If you're lucky you can find one with a groove for the Circlip that is in the right place near the end. For the rest of it and to trim it to length, you can do that for yourself too:

Making and Replacing a Brushless Motor Shaft - http://www.rcgroups.com/forums/showthread.php?t=1240725

If you want some help getting the motor apart, the start of this thread will help:

Outrunner Disassembly and Stripping - Gimbal Motor Rewind - http://www.rcgroups.com/forums/showthread.php?t=1823636

As far as the bearing life, motors in RC planes are pretty vulnerable to damage to I consider them to be good for as long as they last. But bearing are cheap and easy to replace. If you buy the best bearings they still need to be lubricated, the amount of extra power you'll get from them is probably too small for us to measure with common tools and methods, and the expensive bearings seem to magnets for running into things that will damage them.

Good luck with it, nice looking motor,

Jack
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