HOLE FLOW!!! HOLE FLOW!!! HOLE FLOW!!! HOLE FLOW!!! HOLE FLOW!!! HOLE FLOW!!! HOLE FLOW!!! HOLE FLOW!!! HOLE FLOW!!! HOLE FLOW!!! HOLE FLOW!!! HOLE FLOW!!! HOLE FLOW!!! HOLE FLOW!!! HOLE FLOW!!! HOLE FLOW!!! HOLE FLOW!!! HOLE FLOW!!! HOLE FLOW!!! HOLE FLOW!!! HOLE FLOW!!! HOLE FLOW!!! HOLE FLOW!!! HOLE FLOW!!! HOLE FLOW!!! HOLE FLOW!!! HOLE FLOW!!! HOLE FLOW!!! HOLE FLOW!!! HOLE FLOW!!!

Silly... ELECTRONS... Sheesh! What are you going to tell me next?

Sorry, but mrasmm is right in that you can view current flow from either a positive or negative direction. It doesn't matter. We used to get into arguments about this back in the Navy. I've found that it all just depends on what happened to be in vogue at the time you learned.

Couldn't resist!

Drilling is a very good idea ! ! There is a space between the permanent magnets that could allow for drilling. I think that is interesting.

The heat issue alone is the only reason I upgraded and saw a difference. Some say that they feel more power, but I don't know. I agree that they are a bit quieter. The comm is thin as paper, so I don't know if the longevity is there even with the bearings if You wear through the comm. If You pay twice as much, and are only able to replace the brushes once or twice before the commutator wears out, then I wouldn't be gaining as much.

I like the fact that they run cooler and are quieter, but I would be interested in power if WXUP wants to test that; I wonder if He's set up to do that? I think His methods would be more geared to test something like that more accurately. One could test that with the engines naked, I would think; but I don't know. If He could do that, I would definately listen and take Him at his word, as I think He's on the right track with the methodology. He knows the steps.

I'm really not set up to do any of that.

From what little bit about electric motors I do know, power output should be the same. For instance with the medium sized motors we carry at work, a 15hp motor is a 15hp motor. Doesn't matter on brand they are built to the same performance curve. However, the components that each motor is made of makes a difference when we speak of power draw to run them. As stated above, better windings, better bearings, the list does go on will have a large effect on the performance of the motor as well as longevity, quietness, etc. etc. Thus you can buy a "high performance" 15 hp motor vs. an "economy" 15hp motor. Both motors have the same output ratings however their consumption ratings vary greatly due strictly to the components they are made of and you will pay a premium.

I would like to think that the stockers are "economy" and the Xtreme are the "high performance", from my view I would have to say I am correct with thinking they are a performance motor as they do offer benefits over the stockers.

Just my 2 cents.

lol. . . (Bry)

http://www.physorg.com/news98111007.html carbon can be magnetic lol =P (not that it has anything to do with this)

I'm not saying that what I said about the other is necissarily true, I'm just saying that's the way I had it explained to me and it seemed to make sense. I don't know what the actual phenomina is.

A few things that you can prove is the electricity in a DC arc welder with regular polarity (ie ground is - and the stinger is +) that the arc jumps from the metal to the torch, and with lightning it jumps from the ground up to the sky (if you watch storm chasers they had a really good camera shot of that on this last episode), and a few things like that. That's probably trivial though, and doesn't really help explain all of this.


yeah, I would agree, personally I think the Xtreme motors look like the way to go. I wonder, has anyone tried to see if the whole armature shaft and comm from the stock motor will fit in the Xtreme? If someone wanted to do a bit of surgery then you could just swap that out. I know I've done some small n20's before that I had to keep the armature and shaft but swap the comm, that's alot of really fine soldering and being really careful not to crack the comm apart, but if you just could replace the whole thing (like if it had the same amount of resistance and close to the same amount of windings and gauge), maybe it would be worth it =) I dunno though how the endbells on the Xtremes attach.

that would be kinda cool to test that to see what the efficiency ratings at different loads, different amperages and different currents would be of the two motors. I know that hobby sites give you that info, but I'm not sure how they test that, like some kind of dyno or something with a nice adjustable power supply, and that info might already exist somewhere =)


yeah, and RPM's, and efficiencies at different power bands could also come into play, and how efficiently they handle the PWM signal. Lotsa variables... too many for me =)

i'm outa the loop, what's hole flow!!!?

Electron flow would be like saying every morning thousands of cars travel from the suburbs to downtown. Hole flow would be like saying every morning thousands of parking spaces travel from downtown to the suburbs!

wxup, That is a great way of describing that! [8D]

Hole flow is an abstract way of looking at current flow. We know from electrical theory that the electron, with its negative charge is actually the "carrier" if you will, of current flow. However, if you think about it, when an electron gets knocked out of its valence shell / band, it leaves a "hole" behind that wants to accept an electron from the atom behind it, so to speak. So, even as the electrons flow from negative to positive, the absence of electrons (or electron "holes") - the potential to accept an electron in the valence band - moves from positive to negative.

In electrical theory, you have several rules of thumb, for example there is the "right-hand rule for coils" that allows you to know the orientation of the magnetic field produced when current flows through the coil. If you view current flow from positive to negative, you use your right hand, wrapping your fingers around the coil in the direction of current flow and then your thumb points towards the North pole of the (now) electromagnet.

If you are an electon flow person, where current flows from negative to positive, then you would merely substitute your left hand for the right and the thumbrule is still valid.

In an arc welder the current has to flow from the torch to the metal to carry the metal from the rod to the peices being welded. Same as electro platting, anode and cathodes, ones positive and one negative, current flows from one to the other takin with it metal and then bonding it to the part. Also the same with powered coating.

mrasmm:
I appreciate that you see the advantages of this type of testing. I also appreciate your comment about keeping the dialog constructive. I believe if we work together on this, simulation testing can add a valuable tool in comparing all the different aftermarket products out there. Rotor blades are a good example of this.

I think you provided the puzzle piece we are looking for when you mentioned the 4 in 1 output being PWM. My understanding was that the output was variable voltage: that's why I went with the power supplies to maintain constant voltage. The fact that the output is PWM completely changes things. I will have to modify my setup to use the 4 in 1 to provide speed control. I can monitor the pulse width with an oscilloscope to maintain a consistant power level to the motors. Once I have more run time on the Extreme motors I will repeat the testing and see how these two changes affect the data. Once we get a correlation we can look at what other tests might be considered useful.

yeah, that is defiantely the theory, but when you watch a DC arc welder on high speed, it goes backwards of what you might think, so I'm not exactly sure what is going on there. You can also reverse the polarity on alot of welders and make the tip - and the object + I forget what it does, but I do remember working on machines that were able to do that. Also there are AC welders that use AC current to make the weld.


yeah, not a problem. Like I was sayin, with the different methods and the real vs the lab and all of that we should get some pretty well rounded results from all angles IMPO, and hopefully they end up saying the same thing =P

sounds like you've got quite the setup to test all of this =) that will be pretty cool to see what kind of "lab" results you get from what you're gona test. When you test it, if you can get the info pretty easily, I'd like to know what the sample rate is on the stock ESC's. Is it something like 1024hz?

mrasmm,
The frequency is 4.2KHZ. The duty cycle jumps from zero to 26% when the rotor starts turning, then slowly ramps up to 86.5% at max throttle.

Hey, Guys

Sorry to interrupt,

Can I go about half as light with the guage on the XTREME motor wires and not worry too much about increased resistance, heat and power loss. I need to shed some more weight with this heli.

How small of guage do You think I can get away with?

Thanks in advance.

Gary

wow, that's some good info, thanks =) I would have never guessed it was that high (step). I've got a GWS ics100 ESC that has a 2048 step, and it seems to offer better control than the stock 3 in 1.



my guess would be something around 22ga, you're only looking at about 4A that you need to carry

I ran some more tests and came up with some interesting information. Now that I have more run time on my Extreme 180 motors, I re-ran the previous test and found that the Extreme motors do in fact run cooler once they have been broken in than when they are new. The temperature rise when new was 43 degrees F, while the temperature rise after being broken in was 32 degrees F. I must say I’m surprised to see that much of a difference.

The next thing I set out to do was test heat sinks. I found several that I thought might do a better job than the stock heat sink, so I tested them. Unfortunately (or fortunately, depending how you look at it) none of the other heat sinks I tested outperformed the stock heat sink. Good job E-flite! So the next question was, if one stock heat sink is good, would two be better? It might be worth the 3.6 gram weight penalty if the second heat sink helped the motors to run cooler. Once again I was surprised. The motors did not run cooler with the second heat sink installed.

So the question is, what next? I was thinking about looking at rotor blades; maybe comparing thrust vs. power? Any other ideas?

I would love to know the results of the, now broken in, Xtreme motors with and without one heatsink.
How much cooler do the Xtreme motors run with the heatsink now verses no heatsink at all?

Yes, it would be interesting to know this so that you could then estimate the net heat contribution of the motors versus the 3-in-1.

I appreciate all the research even if it's not perfect. I'd like to hear more discussion and less argument over who's test is more accurate. I think the more tests and done in different ways, the more we learn. No one way is probably "right".

How about wattage differences between the setups to attain hover? This would obviously effect run times.

Wolfpackin:
I'll do a run without the heat sink when I can and post the results.

BryFlyGuy67:
I'm not sure what you meant by "estimate the net heat contribution of the motors versus the 3-in-1. ". Can you explain that a little more?

rweatherford:
That was one of the things I set out to do, look at the power each set of motors needed to hover the heli, to see if the 180's would give longer run time. But since the motors are controlled via PWM, that makes power hard to calculate. I can measure the percentage of on vs off time and tell if one set of motors is using less power than the other, but converting it into watts is more difficult.

mrasmm:
I just read your "Electric Brushed Motor Break-in Guide". Very informative. I was wondering what you thought of the idea of spinning the motor with a drill motor or equivelent rather than putting power to the motor to break it in? If all we are doing is abrading the brushes until their shape matches the armature, it seems that should do it. Do you think running current through the brushes helps in the process?

Wolfpackin:
Here's how it breaks down:
stock motors - broken in - no heat sink - 55 deg. F temp rise
stock motors - broken in - with heat sink - 42 deg. F temp rise
180 motors - new - no heat sink - 56 deg. F temp rise
180 motors - new - with heat sink - 43 deg. F temp rise
180 motors - broken in - no heat sink - 49 deg. F temp rise
180 motors - broken in - with heat sink - 32 deg. F temp rise

What I meant was that there are really two major heat contributors inside the "canopy": the motors and the ESC / 3-in-1. I would be curious as to the relative heat contributions from each component, though this would be diffcult to measure.

Does that make sense?

BryFlyGuy67:
Yes, I see what you mean. I usually think of the 3-in-1 as something affected by heat rather than something generating heat, but you are right, it does generate some heat itself. Although I think the amount is very small compared to the motors. And I think you are right that it would be hard to measure. The motors would have to be removed from inside the canopy, but still drive the rotors, so you could measure the heat rise due to the 3-in-1.

Well, if you think about it, all of the power (voltage and current) have to pass through the MOSFETs inside the 3-in-1, so there's definitely some new heat contibution there. I wish I had a thrermal camera. That you tell you fo sure, right away. Buuuut, I don't have $5000+ to invest in one of those just yet.