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Old Oct 14, 2009, 09:53 PM
Dave North
timocharis's Avatar
USA, CA, San Jose
Joined Apr 2004
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Quote:
Originally Posted by Truglodite
...one was 1.5" longer... I'm guessing that was a "late night" wire and I put on an extra turn.
Ouch. There's the culprit. And just to make it worse, you had to actually cram on an extra turn to make the mistake! Sometime going that extra mile ...

Good news is the next one will probably work if the stator insulation held up. That stuff probably will.


Dave
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Old Oct 15, 2009, 02:01 AM
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Carmichael, CA
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Quote:
Originally Posted by lance dalton
Check out a motor I ordered 24 slot This could be a fun rewind or a nightmare .

Lance
I was checking those out a few weeks ago and passed on 'em based on test data in the HK reviews. On the up side the windings look horrible in the HK picture, and it looks like they finally listened to somebody and gave plenty of room in front of the stator. Plus just look at that thing... you'll have a rewound giant neutrino, and there's something to be said about that.

From a winding standpoint, it looks like the perfect break from the daily grind of 12n stators. Please let us know how it goes Lance, and good luck.

Cheers,
Kev

[edit: Dave, I got a laugh out of that. ]
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Old Oct 15, 2009, 02:25 AM
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Chino Hills, CA.
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One guy posted 10.81 volts / 6.24 amps / 7980 rpm on a GWS 8x4.3 SF. On Badcock that's about 13.7 oz. but only 63% efficiency.
Can't wait to get it but HK has held up my order for over a week .

Here's a thread where they opened the 1800kv up Turnigy 3020 1800kv . The 1200kv might have a different mag count.

This could be interesting .

Lance
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Old Oct 15, 2009, 04:47 AM
homo ludens modellisticus
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near Nijmegen, Netherlands
Joined Feb 2001
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Quote:
Originally Posted by Fishjunky
... How do you figure out what the Kv will be per wind? ....
Do a quick'n dirty 10-20wind job with thin wire and ...
http://www.rcgroups.com/forums/showt...9#post12707779

Winding one phase would be enough, it would give you the Kv for the delta termination. Kv_wye = Kv_delta/1.8

Vriendelijke groeten Ron
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Last edited by Ron van Sommeren; Oct 16, 2009 at 04:52 PM.
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Old Oct 15, 2009, 12:05 PM
Dave North
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USA, CA, San Jose
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Quote:
Originally Posted by lance dalton
One guy posted 10.81 volts / 6.24 amps / 7980 rpm on a GWS 8x4.3 SF. On Badcock that's about 13.7 oz. but only 63% efficiency.
Looks like the 3S might be the way to go. Mine came in and managed 8179 rpm 2S with the 0843, which is a nasty-bad 52% at best. With the 8040 it improved to 63-65 percent efficiency, which still sucks hard.

The 1800 as you already know is 22mags 24poles dLRK. They used an asymmetric wind (9-10-9-10) to get 9.5 turns delta. It was 28awg wire (or close) and a trivial wind, much like the Neutrino. The machining, coating and winding were all superior to the sample Neutrino I took apart, and no glue was used on the windings.

I'm thinking either 16 turns 28 to go 3S delta or maybe 10Y something fat ... hmm. Lemme think. But starting with such feeble efficiency does not bode great things.

We shall see.


Dave
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Old Oct 17, 2009, 05:42 PM
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Quote:
Originally Posted by timocharis
Looks like the 3S might be the way to go. Mine came in and managed 8179 rpm 2S with the 0843, which is a nasty-bad 52% at best. With the 8040 it improved to 63-65 percent efficiency, which still sucks hard.

The 1800 as you already know is 22mags 24poles dLRK. They used an asymmetric wind (9-10-9-10) to get 9.5 turns delta. It was 28awg wire (or close) and a trivial wind, much like the Neutrino. The machining, coating and winding were all superior to the sample Neutrino I took apart, and no glue was used on the windings.

I'm thinking either 16 turns 28 to go 3S delta or maybe 10Y something fat ... hmm. Lemme think. But starting with such feeble efficiency does not bode great things.

We shall see.


Dave
Great info Dave!
Glad your in my corner on this one .

Still haven't received mine , but at least it was finally shipped. Very nice looking motor and glad to hear it's made well. Have you been able to get any wire on it?

I did get my R&B 3000kv dLRK. I might try a 12T 24awg dLRK Wye to compare to the 12T ABC.
At first glance I thought the bell on the R&B was anodized. I think it's painted after looking at it.
Looks well made with thin head stators . I'll be following your tutorial and I liked the dLRK wind for Delta termination. Very nice "How To".

Lance
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Old Oct 17, 2009, 06:02 PM
Dave North
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Quote:
Originally Posted by lance dalton
1. Have you been able to get any wire on it?
2. I might try a 12T 24awg dLRK Wye to compare to the 12T ABC.
No winding yet. I think I want to use 28awg and I don't think I have enough.

Comparable wind, due to the natural difference in Kv (14 mags dLRK vs 16 mags ABC) is 13 turns 24awg (and part of the reason you'll sometimes see an efficiency edge to the ABC). You can do it!


Dave
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Old Oct 17, 2009, 06:41 PM
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The 13T 24awg dLRK that you wound put out excellent #'s. Ron (Daoldguy) says it runs soo smooth.
OK, it'll be a 13T dLRK.........attempt .

I have no 28awg either. Found 30, 26, 24 , 23, 22awg but no stink'n 28....ARGH . I'll have to see if I can get my fingers on some. What fat size wire were you thinking for the 10Y?

Lance
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Old Oct 17, 2009, 07:03 PM
Dave North
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Quote:
Originally Posted by lance dalton
What fat size wire were you thinking for the 10Y
That looks like it would have to be 26g to really be cool, but I don't know if it would fit (probably not, but maybe. Experimentation proceeds). 10Y 27 is good, but I think 16D 28 is possible, and that would be better than 10Y 27.

However, if you have 30, you can try for something spectacular, like a 20 or 32 parallel <-- 32 that would be a woohoo! I'd probably try a 21 or 22 parallel Y and see what happens; keep it soft and see what kind of efficiency is possible.


Dave
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Old Oct 17, 2009, 08:19 PM
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I was wondering what the convention is on reported (no load and loaded) current numbers: Do you give the raw current from the logger, or is the idle current of the esc subtracted?
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Old Oct 17, 2009, 08:50 PM
Dave North
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Quote:
Originally Posted by rloberlin
I was wondering what the convention is on reported (no load and loaded) current numbers: Do you give the raw current from the logger, or is the idle current of the esc subtracted?
It would probably be best to subtract the idle current, but I'm just reporting the logger's record. Do you know of a trustworthy way to measure the ESC draw for Io readings?

Dave
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Old Oct 17, 2009, 10:06 PM
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What I had in mind was just subtracting the average draw of the esc before the throttle was turned up (I am assuming Io is just the current at full throttle with no prop mounted?).

The reason I was interested was that I was trying to figure out what was going on with a rewind I tested. It's 14 turns 25 gauge ABC Wye. The measured Io was .89 amps. If I subtracted off the esc idle which was .44 amps then I am in the ballpark of your stock numbers from the spreadsheet (.48,.36,.37). But since your numbers are right off the logger, I guess I probably have a short (which would explain the lousy efficiency I was getting ).

-Richard
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Old Oct 17, 2009, 10:14 PM
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While I'm at it, are the listed Kv numbers usually from a Dremel test, or are they somehow calculated from other data?
Thanks!

-Richard
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Old Oct 17, 2009, 11:48 PM
Dave North
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Last first: I think Kv is arrived at in a variety of ways around here. Dr Kiwi uses a calculated result from Io and a calculated Rm. Mine are the result of measured Io and measured Rm. However, the Io does not allow for the ESC current draw, which I was able to somewhat determine.

For one thing, it's not constant at all on my ESCs. A cheapo I had read from 0 to 0.03 amps @ 8.2v. Using the same battery, my Tbird9 and P10 Castles both read about 0.05 amps, dithering between 0.02 and 0.08. The larger P25 read out an average of 0.08 amps. I'm not sure that draw stays the same as you ramp up the motor, though.

At some point I'll try an extended test with various motors hooked on and get a calculated average. Interesting, but I'm not sure whether it's useful.


Dave
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Old Oct 18, 2009, 12:23 PM
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One way to gauge whether the correction is useful might be to test the Io of the same motor at the same voltage on a bunch of esc's and compare the variance of the corrected data vs. the variance of the uncorrected data. If the corrected data gives just as much noise, then it is not really helpful for the purposes of people comparing results (whether it would help for the motor formulas could be a separate issue).

Anyway, it looks like your idle currents are pretty low so they are probably not worth worrying about. I guess I'm getting such high values since I'm testing on a tied down plane I'll try to reduce them by unplugging the servos, and I'll throw a cheap servo tester in the next HK order so I can ditch the receiver.

When you say that you are calculating Kv from Io and measured Rm, you mean Io, measured Rm, and no load RPM, right?

-Richard
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