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Brushless motors - reliability survey

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David Ashby - Moderator11/04/2012 11:05:07
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I was chatting to a certain Mr Fenton wink 2 yesterday and we turned to the subject of brushless motors and the price disparity between top-of-the-line products and cheaper items.

I've been flying brushless for 8-9 years now and in that time I've never had a motor break or malfunction. I've never had magnets fall out or windings unwind or anything else that could go wrong.

I guess the more expensive motors I've used do exhibit good or low current draw in comparison and they can be notably smoother.

So, all-in-all, the reliability has been impressive and at all price points. It seems like we've never had it so good?

Has anyone noticed any particularly unreliable brands?

 

 

Edited By David Ashby on 11/04/2012 11:05:59

David perry 111/04/2012 11:18:55
1054 forum posts
13 photos

No. I make a point of using the cheapest motors I can get away with (currently the Robot Birds Budget brushless, the bronzey gold ones) and they are superb. Weve trashed a few in our day but never had one fail!

D

Chris Bott - Moderator11/04/2012 11:45:17
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I have used mostly the cheaper brands and find them pretty good. I've also trashed a few but only by testing how far I can go beyond the manufacturers specs. This is something I would never contemplate with a motor I've paid a lot of money for. So an expensive one tends to stay reliable for me for that reason.

One thing that I see as a huge advantage with the expensive/branded motors is repeatability. If you find one you like they it is probably going to be available for some time.

With the cheaper ones, not only do they come and go, new ones come along all the time that we have no experience of, which doesn't help build up a good reliable knowledge of motors and their applications. I've also found that the same make and spec of motor can even be different if from different batches. This too adds to the buy it, cross your fingers then suck it and see nature at this end of the market.

I'm not convinced they are much worse on current draw and efficiency, just that you're never 100% sure what you're going to get. But then the price means you can experiment, and one that doesn't suit one model will come in handy for another.

Steve W-O11/04/2012 11:50:41
2775 forum posts
310 photos

As I posted a couple of days ago, the bearings went in my Funcub motor, but less than a pound to replace them both. There is a posibility the motor could have been used in a rotovator experiment before I fitted it to the Funcub, I can't remember.

I use Turnigy or any inexpensive motor, and have never had a failure, and I don't think the efficiency is bad.

I do check the quoted specs, especially the winding resistance, and alter any calculations to take the actual readings if they are more than a couple of % different.

The only bad motor I had was the one supplied with the wot4faome, where the motor windings were all different.

Some of the cheap ones seem to take too much effort to get the shafts out to change them around, but that is my only negative comment with cheap motors.

Cyclicscooby11/04/2012 11:57:52
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874 forum posts
531 photos

I've had one motor die, but that was me overloading it... It even started making a strange noise a couple of flights before, but I didn't click, until it dead-sticked.. It was only £12 so not the end of the world and my fault anyway..

I have 3 E-flite motors (Pwr32-Prk 480-Prk280) which have been faultless on 2 E-flite Esc's and another

I buy Overlander at the mo, which is the cheapest LMS motor.. About 1/3 the price of E-flite.. Don't sound quite as smooth if i'm honest, but they still perform..

A Tornado motor on my Edge foamie has had a few hard landings and broken props in the beginning, but is still dead smooth and quiet

I really can't fault brushless... Amazing leap for our hobby..

I'd like to get a BL setup for my RC cars, but they need sensored motors (for low rpm) and are still horrifically expensive...

Luv

Chrisie.. xx

Allan Bowker11/04/2012 12:57:14
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1636 forum posts
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Not had a problem with either cheap or expensive motors large or small when used correctly within manufacturers specifications. I've smoked two motors but that was due to my inexperience at the time and once trusting what a seller told me without checking myself. Problems were my fault and not down to the motors.

Some of the motors I regularly use:

  • Turnigy Aerodrive XP C6354-250 (70" Hangar9 Funtana) - Hobby King
  • E-Flite Power 60 (Hangar9 Pulse XT60) -Suggested  Brand/Type for Model
  • Himax C3528-1000 (Multiplex Mentor) -Suggested  Brand/Type for Model
  • Himax C3516-1350 (Multiplex Blizzard) -Suggested Brand/Type for Model
  • E-Power BL2815 (ST Models MX2) - Giant Cod
  • Emax B2846 2800kv (Parkzone Stryker) - Giant Cod
  • Emax 125w (Wild Hawk + Profile Edge 540) - BRC Hobbies
  • Turnigy (many various small outrunners 20w-300w) - BRC  / Hobby King

I tend to find that a good quality ESC helps a motors performance rather than the motor being the issue. ESC's however should be a thread all on their own!

 

Edited By Allan Bowker on 11/04/2012 12:59:32

Richard Wood11/04/2012 12:57:27
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1096 forum posts
164 photos

Never had a problem in the last five years or so with thrown magnets,

loose wires or windings with any motor.

I have found that some cheaper motors - such as 'EMP '- can be a bit rough

& noisy (some very noisy) however.

Also found that identically spec'd cheaper motors with different 'labels' often

vary significantly in performance - such as current draw on a particular prop.

making selection a bit uncertain.

My preferred choice has been Scorpion as they are very well made, powerful,

& quiet, but are not so easily available these days as Micron have scaled down.

 

 

Edited By Richard Wood on 11/04/2012 12:58:44

Trevor Crook11/04/2012 13:03:57
967 forum posts
69 photos

Cyclicscooby

I use a relatively cheap brushless setup in my RC touring car. It's a 13 turn sensorless motor, which I got with ESC and programming box from Giant Cod a year or so ago. I paid around £65 for the lot. It's branded EZRun, and has performed faultlessly. Don't know if it's still available, but GC certainly stocks some car set-ups. I don't find any problems with it being sensorless, but I believe the BRCA insist on a sensored set-up for their competitions (who knows why?). Since I race casually in a local club, I'm not bothered.

Trevor Crook11/04/2012 13:08:51
967 forum posts
69 photos

Oh, and back on topic, my experience and opinions on cheap brushless motors in my aircraft exactly matches Chris's above. I'd settled into using E-Max from GC, but he doesn't seem to stock many any more, which backs up the point that Chris made about them coming and going. Have to choose something else for the next project, but I'm not too worried as whatever I choose will probably be fine.

Frank Skilbeck11/04/2012 13:29:26
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4730 forum posts
101 photos

I have a complete mixture of motors, my oldest being 3 AXI motors which have been inseveral planes, then a selection of Turnigys. E Max and other budget makes, plus all the ones on the Parkzone BnF models.

Only had one motor fail in all that time and that was an OEM in a high power foamy (1200w) where the magnets cames loose, was replaced by the supplier and new motor has been OK (so far).

ESC's have been twice as unreliable though, I've had two fail in 5+ years.

Romeo Whisky11/04/2012 17:03:52
727 forum posts
205 photos

My favourite brushless motors for small models up to 2Kg are the Hi-Model series sold by BRC Hobbies and Airtek and some others (often branded as their own). Superb value and never had one fail. I love their ESCs too.

It's the more expensive motors I've had trouble with. For instance I will never buy an EnErG motor again. I have also heard of problems with Himax motors notably soft shafts prone to bending, and even motors physically falling to bits.

At the cheaper end I don't like the small red EMax series much either because the grub-screw mount fixings wear loose quite quickly, causing vibration. I also had one burn out in a Formosa, when current draw was supposedly well within spec.

Sparks11/04/2012 19:49:13
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266 forum posts
55 photos

In the past I had a preference for Turnigy Motors as they offered good performance for the price. However, the last three I bought have all sounded like a bag of nails from new, replacing the bearings cured the problem but negated the initial price saving. Maybe Turnigy have changed the bearings they use now.

I've been very happy with E-Flite motors (some bought s/h off fleebay) - not cheap, but they do run very smoothly and rugged enough to survive my less than perfect landings.

Erfolg11/04/2012 20:57:57
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11749 forum posts
1337 photos

As many others, I have a wide range of motors.

Reliability has not been an issue to date.

There does seem to be performance differences, expressed as watts per gram.

Higher end are Kontroniks, HET right down to E-Max (approx £2).

Danny Fenton12/04/2012 10:03:25
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9627 forum posts
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I suppose I better throw in my 2p teeth 2

The conversation came as a result of me explaining I was seeking one of these, and have been for a while. Mick Reeves uses them in his 1/4 scale competition models, yes in case you didn't know, Mick flies leccy these days smile o

This is the equivalent to a 50cc petrol and I would like one for a 1/4 scale Hurricane. I have been offered an early version which had issues, the later one is proving very difficult to unearth. Chris mentions in his summary of one of the down sides of the cheaper motors is that they come and go so quickly. And experimentation is only really viable with dirt cheap motors.

The motor above was $102 the equivalent (in power) Hacker is nearly $600 this is a massive disparity. And means that (if you can source them) I can use 6 of the Turnigy's to the single Hacker.

I am with Allan that the smoothness seems to come from a good ESC more than the motor.

Anybody got a 2nd Generation 80-100 they don't need wink 2

Cheers

Danny

 

Edited By Danny Fenton on 12/04/2012 10:03:59

Olly P12/04/2012 10:09:45
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3215 forum posts
181 photos

Ouch, that is a beast!

I've had motors from many brands in most price brackets and have never had a problem. The only ESC that I've had a problem with (which I didn't cause) was the one in my Wot 4 Foam E...

several brands, at different price brackets, are made in the same plant from same materials, so I tend to try cheap ones out....

Keith Simmons12/04/2012 13:24:58
451 forum posts
9 photos

Have a couple of motors and wanted to check GC's stock to find out they match my existing as it's 1/3rd of the price. Any idea when GC will re-stock as they have none in stock of what I want since December. (Have asked them to notify me.)

Will be interesting to see if there is any difference apart from the price.

Erfolg12/04/2012 14:08:39
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11749 forum posts
1337 photos

Keith

I think it is the one issue with GC, they do not always restock an item when it runs out. It could be that they have a policy of looking for value for money, when deciding what to purchase, or plain availability. In the case of the Turnigy motor, it will have a different brand.

Other suppliers simply tell you, that the range has been dropped for their new improved, with whistles model.wink 2

I have found that HK generally do restock, although it can a long time.

Steve W-O12/04/2012 15:47:09
2775 forum posts
310 photos

The bearings on the Turnigy motor of mine that were noisy took only a day to get here, and about two minutes to fit, and less than £1 for the two, more of a recommendation than a problem to me.

The only comment I would make is that when using the shaft for the propeller, the thrust is taken by the smaller of the two bearings, I will probably turn the housing out so that it takes two of the larger bearings, I think there is room. Iy you use it the other way round, with the prop adaptor that screws onto the housing, then the thrust is taken by the larger bearing anyway.

Allan Bennett16/04/2012 20:22:39
1686 forum posts
49 photos

Up until recently nearly all my motors were AXI outrunners, or Mega inrunners in edfs; and none of them have given me any problem.

When I decided to electrifly my two 1.20 models I went for a Hyperion ZS-4045/12 running on 12S LiPo at about 45 amps (half it's ultimate amp rating). My first problem was that it wouldn't run with the Hyperion Atlas 90 ESC, but I cured that by getting (f.o.c. exchange, thankyou RobotBirds) a HobbyWing Platinum 120A Hv.

But then, on the fourth flight, the motor stopped well before the battery should have expired. When I landed the model I could smell burning, and it turned out it was the motor. With the motor out of the model it felt like a bearing was gone, and it was clear that one winding was burned. RobotBirds exchanged it for a new one after getting the go-ahead from Hyperion, but it didn't feel "right" when I turned it by hand, so it went back and RobotBirds sent another replacement.  This one had small bits of swarf still attached to the drilled cooling holes in the front, but felt okay so I ran it for the first time yesterday after cleaning out the holes. My problem now is that I'm a little wary of this motor, so I got a Hacker for my other 1.20 conversion.

Edited By Allan Bennett on 16/04/2012 20:27:01

David Molineux08/05/2012 23:40:56
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123 forum posts
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Slightly off topic I suppose but I had an 'unplanned arrival' the other day and when I ran my motor to see if it was ok, it doesn't sound quite the same as before. A bit more 'mechanical'. It seems to run ok but I'm worried the bearings may be damaged? Is there an easy way I can check?

Cheers,

Dave.

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