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E-Max 2210/30 Question

Old 04-24-2011, 11:35 PM
  #1  
Tenderfoot
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Default E-Max 2210/30 Question

I installed an E-Max 2210/30 and assumed that the Amp rating of 15 on 3s LIPO would be OK according to the data on several different web sites. I learned that motors don't smell too good when they get really hot and start smoking, so I rechecked the numbers and the reccommended prop size (up to a 10x5) and figured I really didn't know what I was doing. So, the question is does anyone know what size prop I put on this motor to stay within reason and have a long and happy relationship with my wife over how much money we should spend on Fabreeze??

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Old 04-25-2011, 12:43 AM
  #2  
flydiver
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10x5 on 2S was likely too much. It's common for motors (batteries, ESC) to have their specs over-hyped. A good rule of electronic survival is to de-rate everything by 20% until PROVEN otherwise.

Here's some interesting data showing the 10x5 pulling over 15A on 2S. You were likely pulling into the mid 20's.
http://www.flybrushless.com/motor/view/60
On 3S 7x5 may be more like it-maybe.

Often a range of sizes is suggested. Often (but unfortunately not always) the larger prop size is 2S and smaller one is 3S.
There is also a tendency for LOTS of people to over prop so take recommendations as a starting place and not necessarily wholly valid unless they can give you detailed support (wattmeter readings, temps, thrust, etc.).

When you bench test (NO COOLING-potentially harmful) it's best to start with no more than 15 seconds and do a touch test. Warm is OK. Too hot to touch any component indicates a problem needing rectification before proceeding.
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Old 04-25-2011, 12:51 AM
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CHELLIE
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Here is some great info from Dr Kiwi at RCG

http://www.rcgroups.com/forums/showthread.php?t=570207

E-MAX brushless outrunners from XUS Hobby
XUS Hobby sent me three E-MAX brushless outrunners to test. The tech-specs from their website, and/or on the packages, for the three models I received are as follows:

Note that the 2212 is now known as the 2812!

E-MAX CF 2212 (1534Kv), 40g, dimensions 22mm x 10mm, max. eff. current 7A-16A 82%, (16A max/60sec), no-load 0.9A (@ 10v), Rm 0.150 ohm, for 2-3s Lipo [only prop specifically mentioned 7x6)

E-MAX BL 2210/30 (1400Kv), 45g, dimensions 28mm x 20mm, max. eff. current 8A-12A >75% (17A max/60sec), no-load 0.9A (@ 10v), Rm 0.150 ohm, for 2-3s Lipo [only props specifically mentioned 10x5, 10x4.7 SF)

E-MAX BL 2215/25 (800Kv), 59g, dimensions 28mm x 31mm, max. eff. current 82% 8A-13A, (17A max/60sec), no-load 0.5A (@ 10v), Rm 0.116 ohm, for 2-3s Lipo [only props specifically mentioned 10x5, 10x4.7 SF, 11x5.5)

Nowhere could I find information on the number of turns or winding wire gauge.

I have some concern over the “Recommended prop without gearbox” information given on the website – each of the three sizes of motor I received has its own data page, but each comes in two different versions with different Kv. For example, the CF 2212 (1534Kv) shares a page with the same size (40g) CF2822 (950Kv), the BL 2210/30 (1400Kv) shares a page with the same size (45g) BL 2215/25 (2100Kv), and BL W2215/25 (800Kv) shares a page with the same size (59g) BL W2215/20 (1260Kv). Yet no distinction is made for the “Recommended props” – the CF2212/CF2822 page lists 8x3.8, 9x4.5 and 10x5 – none of which would be suitable for the CF2212 on 3s (or probably even 2s). Certainly, at the bottom of the pages, there are “Examples of use” – such as for the CF2212 7x6, for the CF2822 10x5 – but nave users could well go for a much too large “Recommended prop” with disastrous effect.

[Another oddity is that the single Io and Rm values given, apparently apply to both versions of each size of motor, though they have very different Kvs? Similarly no distinction is made as far as “maximum current” is concerned for the CF2212 v. the CF2822, nor for the two versions of the BL W2210].

These minor inconsistencies can obviously be easily remedied by a careful editing of the information pages.

The motors have 3mm shafts: they come with 3.5mm bullet connectors fitted, and a selection of accessories: matching female 3.5mm bullets, X-mount and screws, aluminum prop saver with locking screws. The motors seem well-machined and finished, and as you can see from the photos, the CF 2212 is anodized red, the others are blue. All three were configured with the shaft protruding from the bell. The back-plates have the standard 16mm/19mm spaced, 3mm, threaded holes.

Each has a label around the bell, with model number, prop range (simply e.g. 10”-11”) and 11.1v (indicating suitability for 3s usage).

I used my standard test stand set-up: Thrust stand [Version III in Pusher mode], Ohaus CS2000 Digital Scale, Zurich Power Supply, Medusa Analyzer Plus, FMA 5 Rx, Futaba Skysport 4 Tx, Phoenix 25 and Hacker X-20 ESC’s, Hobbico Digital Mini-Tach, RayTek IR temperature gun.

As you can see from Photos #1 and #2, I made a Rube Goldberg mount for the CF 2212, bolting the circular rear mount to a Todds Models 2000 gearbox frame. The CF 2212 has a VERY short bearing tube and none of my stick mounts could accommodate it.

Photo #4 shows my sliver of 1/64" ply, used as a pseudo prop to determine no-load rpm. I measured 0.8A @ 7v and 11250rpm, 0.9A @ 8v and 12900rpm, and 1A @ 10v and 16020rpm - the XUS Hobby site stated 0.9A @ 10v.

So far I have only tested the CF 2212, and, briefly, the BL 2210/30.

With the CF 2212, I tried a selection of props from 5.25x6.25 APC E up to 7x6 APC SF, running full series (WOT for <20 seconds, just long enough to write down the data – volts, amps, watts, thrust, rpm) with the PS set at each of 7-8-9-10-11v. I also tried an 8x4 GWS HD on ~2s voltage (7.0v and 7.5v on the PS). The motor ran well enough on all the smaller props up to the 7x3.5 GWS HD, but mindful of the very high 1534Kv and seeing the amp draw with the 7x3.5, I knew I’d be in trouble with the recommended 7x6 APC SF. The manufacturer’s data indicated that this prop could be spun at 11000rpm @ 15.5A and generate 730g (25.70oz) thrust. Even at only 8.9v this prop drew 14.7A and the motor couldn’t cope. At 9.9v the amp draw reached 17.0A, but the motor only briefly managed 9720rpm and 475g thrust. The amp draw/rpm plummeted while the temperature at the windings soared to ~65C. Enough was enough! [I had one minor problem during these runs - the bell on the CF 2212 is secured by two small set screws (1.27mm hex), and it came loose during one of the runs - I had difficulty getting the set screws tight enough to hold it securely and ended up using a little Loctite 638 to make it secure.]

Later I tried the 7x5 APC E and managed a full series – but averaging about 12A [peaking at 16.50A @ 10.9v] generated so much heat that, at the end of the run ( five bursts of ~15 sec), the temperature was an ominous 75C.

How the stated E-MAX performance numbers were derived is a mystery to me, because I certainly cannot match them! Intuitively, it is hard to imagine a 30g, 1534Kv motor managing to spin a 7x6 APC SF on 3s, without drawing massive current and over-cooking as it does so.

I have tested a few small motors of similar Kv. From “current draw with the same props”, the CF 2212 appears most similar to the Torque 34T/1520Kv, the Hacker A20-34S (1500Kv), the prototype LS Purple Peril (?1580Kv) and the Custom CDR Hot wind (somehow I have a note of ?1810Kv for that – surely not).

With the BL 2210/30, intuition again suggested that the recommended 10x5 APC E would not be suitable for a 45g, 1400Kv motor. I began with an amp-miserly 8x4 GWS HD to “test the waters”. At only 8.9v the motor was already drawing 12.10A and struggling to maintain amp draw and rpm – at 10.9v amp draw had reached 15.50A and the motor temperature had soared to 75C. I let the motor cool down, then tried the recommended 10x5 APC E. E-MAX data suggested that this prop would draw 17.00A on 3s (11.1v), and produce 780g thrust @ 7000rpm. At only 7.8v it was already drawing 15.70A (getting 558g at 6330rpm) – and again it was struggling and the temperature rapidly reached 71C. I couldn’t dare try higher voltages. It would seem best to run this motor at no more than 10A-12A. One wonders how E-MAX obtained their figures with the 10x5? Clearly 17A and almost 200W would be over the top! The only comparable motor I can think of, for which I have data, is the Axi 2208/26 (45g, 1470Kv). This E-MAX BL 2210/30 draws rather more with the 8x4 GWS HD (15.50A v. 13.30A @ 10.9v, which is perhaps odd, since it is supposedly lower Kv) – however the E-MAX got a lot hotter (71C) than my Axi did (30C) after the same length of run.

I will try to find time for some further test runs with the BL 2210/30, in the hope of finding more suitable props for it, and I’ll also try the BL 2212/25.

Cheers, Phil
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Old 04-25-2011, 12:52 AM
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Old 04-25-2011, 01:58 AM
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flydiver
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Excellent work digging that up Chellie.
I suggest you spend some time studying how Dr. Kiwi approaches motor testing and use it as a model and future resource. If possible I try to hunt down data exactly like that if I need the info. If not, then the manuf. or dealer's data but with the 20% rule.

All by itself your finger can be one of the most effective tools. You'll not be able to touch it long before it burns up. Once you smell it, electronics are cooking and damage is being done.
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Old 04-26-2011, 02:48 PM
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Tenderfoot
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Default E-Max 2210/30

Thank you for your responses.

The new assortment of propellers and a 2C battery are due in today. My plan is to set up the motor to draw about 10 - 11 amps and monitor the temp. much more carefully. Hopefully, I can try out the new bird this weekend.

Again, Thank you for your help.

Regards,

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Old 04-27-2011, 02:10 AM
  #7  
Sir Crash-A-Lot
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Originally Posted by CHELLIE View Post
That info is for the older motor and may not apply to the motor he has. I sell the Emax motors and the are blue now and not red like in the picture. Also, the 2210-30 is now a 1300kv motor not 1695kv.

We have experimented with the motor and the 8x4 GWS prop on 3 cells seems to be the best. Not sure what the 2-cell best prop would be I don't know anyone that flies on 2 cells.

Tenderfoot,

If your motor is blue this chart does not apply to your motor, if the motor is red then this info is most likely accurate. Dr. Kiwi is VERY good at test motors. A 10X5 prop on 3 cell is WAY to much for that motor the 2220 is a better choice for that prop.

Mike
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Old 04-27-2011, 03:25 AM
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Tenderfoot
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Default 2210/30

Mike,

Than you for the info. My motor is/was blue and it is for sure that a 10x5 on a 3S was a bit much. Even though I may not have the exact numbers, my plan is this. I bought an assortment of props from 6.5 - 9 and a 2S. My test will be run with an amp meter and my finger. The plan is to be able to touch (comfortably) the motor after a 30 second run and hopefully be near 10 amps. The new sailplane is a 2M lightweight (about 30 oz.) and the 2210 is the biggest thing I can get in there without major mods. I feel like it will probably be faster than I need. I will post my scientific findings in a few days. Thank you all again.

Regards,

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Old 10-01-2011, 06:36 PM
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humboldt guy
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Can anyone tell me how to rig up a simple thrust bench? I've searched threads, and find reference to using one, but not how to make one...any advice is appreciated!
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