[Buff]

I posted this question on another site, but haven't gotten a response yet, so I thought I'd get some people's opinions here. The motors I speak of on this post are all new LRP Vector X-11's that haven't been run yet. What I was wanting to do was take the sintered rotor out of the 4.5t X-11, and install it in my 5.5t and use the bonded rotor that came with the 5.5t, and put it in the 4.5t. (The 4.5 is the only X-11 motor that comes with a sintered rotor)...
Here goes:

I'm VERY confused..... I just got done switching rotors.....I took the sintered rotor out of the X-11 4.5t, and installed it into my X-11 5.5t for which I took the bonded rotor that was in the 5.5, and installed it into the 4.5..... Everything went together without a hitch....
* Realizing that (without any knowledge of how to tear down a brushless motor) all it took to remove the rotors from each motor were three screws on the bottom of the can where the pinion mounts....surprisingly easy, as there were NO shims or anything to fall out witch I was hoping wouldn't happen even though I wasn't sure!! *

Ok, now here's what confuses me.....both motors are now assembled fine, everything lined back up perfectly because I marked the endbell, can, everything so that I made SURE I put each motor back together exactly as they were, including the timing which I never changed either. SO, the 5.5t which now contains the sintered rotor, still feels like it did before when it had the standard bonded rotor in it!! :blink: I thought that sintered rotors/magnets were much stronger, hoping to spin the rotor in the can having it feel like it did when it was in the 4.5 can.....but it spun VERY freely as it did with the bonded rotor.... :huh: :\

Why is this??? And vice versa: Now the 4.5t CAN has the BONDED rotor, yet it feels like it did with the SINTERED rotor that originally came with it, by feeling like the magnets were much stronger, more like a brushed motor without the brushes installed and with strong magnets.... (in other words, I figured that the 4.5 can would now feel like the 5.5 did because of the bonded rotor it now has in it???) :blink: :S

In Summary:
So to make a long story short.....both motors feel exactly the same as if I never changed rotors, even though I did. 4.5 now has bonded....5.5 now has sintered....yet they feel exactly the same as they did before the switch when spun by hand inside the can!! I mean, it's VERY VERY easy to tell the difference as the 4.5 STILL stops MUCH faster, while the 5.5 STILL spins almost freely like there are no magnets (as it did before the switch)

My question, WHY???? Does it have something to do with the windings inside the can or did I assemble something wrong??? I made sure I assembled everything EXACTLY as it was because these things are precious and I paid a good amount of money for them and didn't want to ruin them before I even got to run them.

Anybody know what's up?? Will the 5.5 still have more torque though?

 

[FishRC]

Part of the issue might be is the airgap between the rotor and the can. From what I have read that is part of the diferance. The other big thing is without the power applied to a brushless, they will basicaly free spin (Not compleatly, but far less than with the brushed motor.) If the 4.5 is stopping very quicky as you say, I'd look to see if either of the bearings are dirty or worn out. That would more likely explaine the differance.

 

[Buff]

They're definitely not worn.....all my X-11 are BRAND NEW and haven't been installed in a car yet.

But literally, it seems with the 4.5t, it doesn't matter what rotor is in it, the magnets are strong and it's a tiny bit difficult to spin the rotor in the motor by hand....and vice versa with the 5.5 cans....even with the sintered rotor installed in the 5.5t (took it out of the 4.5) it feels as if it still has the bonded rotor in it because it spins very easily, exactly as it did when it had the 5.5 bonded rotor that came in it.

I thought the magnets came on the rotor with brushless, but even though i've switched rotors to different cans, it's made the feel, by spinning with my hand, that nothing has changed. The difference between the 4.5 motor (which is supposed to be sintered) and the 5.5 (which is supposed to be bonded) is very noticeable so it's not even close to tell which one has the stronger magnets....

This is what's confusing me....does this have something to do with how many turns each can has in it???

And my most important question....will there be any performance gain at all with the 5.5 now that it has the sintered rotor in it???????
---(even though by spinning the rotors of each motor by hand, feeling absolutely no difference from how it was stock even though I swapped their rotors)

And again, vice versa.....will there be any loss in performance with the 4.5 because it now has the bonded rotor in it??????
---(even though by spinning the rotor of the 4.5 motor by hand, feeling again no difference from how it was in stock form, even with the 5.5's bonded rotor installed in it, the magnetic strength felt very strong and pretty much identical to how it felt with the sintered rotor that came with it.

I assume the amount of turns each can has, may have something to do with it???? But, I thought that Brent (MX51 on RC10B4.com) told me he wanted to run a 6.5t in his cars with the sintered rotor because it supplied more torque and mid-range power.....

I'm so lost..... and am wondering if I should just switch the rotors back to the cans they came in??

 

[OvalTrucker]

My experience with sintered and bonded rotors has been solely with the Novak motors.
The 4300 guys swear that the sintered rotor is a worthwhile upgrade. And I'm sure it is too. But, the difference is minimal and probably not very noticeable unless your chassis/gearing is darn near perfect already.

I race the 13.5 class and I have experimented with at sintered rotor in that motor. I can't say that my chassis was perfect, but it is pretty darn good. What I noticed with a sintered rotor was increased braking and lower operating temps. No huge difference in torque. Although I'm not sure I had the right gear on it. Gearing changes significantly with the sintered rotor.
The sintered rotor feels way more 'coggy' that the bonded rotor. Hence, the increased braking.

I can't explain the feel you are experiencing by turning the motors by hand. I can feel a definite difference between the two rotors in the same 13.5 can.

I can't tell you if any of what I've said will relate to your X-11's. Just thought I'd add my 2 cents, based on what I experienced.

 

[kevinm]

I've noticed that many of my brushless motors seem to have the "cogging" feel of a brushed motor BEFORE I run them, but it goes away afterward. I suspect that while the motor just sitting around in it's package before you buy it (or even while sitting in your toolbox), the strong magnet in the rotor temporarily magnetizes the steel in the stator (windings). It'll probably go away after you run it a bit.

 

[Andy Olson]

its my understanding of these type motors that the rotor or armature " moving part " isnt magnetised at all. the only magnetic field is in the windings. there maybe some residual magnatism in a rotor but as has been said , its probubly not going to last long sintered or no. nor is it likely to be desireable anyway.

 

[OvalTrucker]

The "moving part/rotor" is the magnet. The windings are in the can and that is what actually determines the performance differences between the motors.

 

[Buff]

The "moving part/rotor" is the magnet.

Yeah, that's what I thought. Here's another post I made on another site which may help explain what I'm having trouble understanding and what I experimented doing:

Maybe I'm not explaining myself correctly of what I'm trying to figure out.... Ok, I"ll put it this way, the ONLY thing I'm looking for is magnet strength and wondering why it is not different when I change rotors from a brushless motor can to another.

I completely understand the windings are in each can now, so you can't change what the motor is without completely changing the cans since the windings are INSIDE the can.....however, the ROTOR is what I'm trying to figure out, and it's strength between sintered rotors and bonded rotors.....bonded supposed to be the standard, sintered being much stronger, allowing the motors to run more efficient, have more torque (more magnetic stregnth).....

The ONLY problem I don't understand.....ok, ALL 3 of my brushless motors right now are LRP Vector X-11's, and they are brand new. One is a 4.5 sintered rotor/magnets (which is the only X-11 that comes with a sintered rotor) and two 5.5t both with bonded rotors/magnets.

Ok, I decided that the 4.5 (with sintered rotor) was going to be too much power for anything but touring car (which I later learned AFTER I had already got the motor) and by learning what people were telling me and (Brent and Coach and many others, sorry if I didn't mention your names, you know who you are!! :rockon: ) I had learned that I eventually wanted to run a 5.5 (which come with bonded rotors) but wanted to take the sintered rotor OUT of the 4.5 and install it into the 5.5 and race it that way in my BJ4 W.E....

Before I made the switch, I made a crude physical comparison, by hand, of magnet strength by simply spinning the rotors inside each motor. Naturally, the 4.5 with the sintered rotor felt VERY strong and is slightly difficult to turn in the can because of it's magnet strength. The I then spun the 5.5 with bonded rotor, and it spun VERY easy because of it's BONDED rotor which isn't nearly as strong.

So, I THOUGHT that if I switched rotors by taking the sintered rotor out of the 4.5, and putting it in a 5.5 can (I would take the bonded rotor out of the 5.5 and actually put it in the 4.5) that the 5.5 can would now have a sintered rotor, that it would have really good magnet strength that it did when when it was in the 4.5....but NO. It (the NEW 5.5 with sintered rotor in it) does NOT have the same strength it did when it was in the 4.5 can, and as a matter of fact, it feels EXACTLY the same as it did with the bonded rotor that was in it. :blink: :S

THIS is what confuses me. Switching rotors didn't do any good for either motor....but especially the 5.5.... and even more strange, the BONDED rotor that is now in the 4.5 STILL FEELS STRONG like it did when the sintered rotor was in it.... :huh: :wacko:

Does anybody understand now what I"m trying to do? The only reason I was thinking it's not working was maybe in the 5.5 can, the spacing between the rotor and windings is further apart than inside the 4.5 can?

Coach? Brent????

Even though this "trade" doesn't feel, by hand, any different when spinning the rotor in each can, will there be any performance gain with the 5.5 with sintered rotor even though it doesn't feel any different magnet strength-wise?????

 

[KOZ]

Question?Have you run the motors on the track? checked lap times?checked runtime?checked temp? You can bench test stuff all you want, it's the on track difference that you see between a bonded rotor vs a sintered rotor..

 

[Buff]

That's not what I'm looking to find out right now, regardless.......what I'm trying to figure out is the question "why" to the question I stated above. I'm figuring somebody knows out there, eventually I'll find out.

It's strange that two motors would still feel the same magnet wise, even though the magnets have been completely swapped from one motor to another.

So in other words, the one motor that had the sintered rotor to start, now has a bonded rotor and should spin freely right?? No....it's still the same, which feels pretty strong as it did to begin with....ok, strange to me. Again, in other words, the rotor is very hard to spin, and stops almost as soon as you spin it by hand.

Now, the other motor that started out with the bonded rotor, now has the sintered rotor in it....it should now be more difficult to spin due to the stronger magnets/sintered rotor right??...No. It still spins freely like it did with the bonded rotor that was in it....it will now spin for several seconds before stopping.

Does anybody understand this???? These motors have to have some type of different performance due to two completely different types of rotors, and I figure if they're switched, they would make another motor perform differently.....and they have to if you can physically feel the difference between magnetic strength just in your hands.....it's not even close, it's like night and day.

I'd just like for somebody to give me an explanation why this is, or what has caused the motors to "feel" the same as they did before trading rotors/magnets.

Doesn't any of this seem strange at all???????

Both motors are also the same brand... Vector X-11's.

 

[signman501]

I don't know much about this, but what about the bearings it the motors? I have only done nitro stuff to this point, just getting into electric using brushless, and bearings can make a big difference.

 

[Buff]

Exact same bearings, and the motors are new, so the bearings can't be bad....they don't feel bad because I spun them when I had the rotors removed to check them.

I've about give up on trying to find out why they are the way they are.....so I'm just going to run them this weekend and see what happens. I'll probably swap back rotors again to see if anything changes too.

 

[cheatr71]

I wish I could help ya buddy, but at the roar race in GB I swapped a Novak 13.5 can for a 4300 can but retained the 13.5 rotor/magnet. My lap times before the swap was 4.3 to 4.5 consistently, after the swap laps went down to 4.0 to 4.2 now explain that. I finally figured out that everybody else is cheating. I ended finishing 11 out of 21 guys but was within 1 lap of making A-main, so handling was not that far off. I ran a Ass.10l40 and beat half the field with a car everybody says to junk. I don't get it,all those other cars are pretty much copy cats of an associated. That opens another can of worms!!!!!! But its true, they all resemble one another.

 

[Buff]

Yeah, I know what you mean there.....I guess the only way I'm going to find out is to run it and switch rotors between runs to see what happens. Switching rotors between cans is a matter of about 15 seconds, so that's nice!! Three screws, pull rotor out, slip in other rotor, re-install 3 screws, done.

I think different types of rotors should be made for motor tuning....different weights maybe, or drilled, something....different types of magnets, sizes, whatever, because it is VERY easy to take rotors out. I didn't know what to expect when I first pulled it apart, but was VERY shocked and pleasantly surprised how easy it really was.

Would also be nice if they made a universal rotor that fit all brushless motors, just different brands and types to change performance that fit all motors.... I just LOVE NOT messing around with stankin' a$$ brushes and comms AND expensive freakin' lathes with 100$ bits that only last so long.

Looks like I've got a Twister lathe to sell, and several brushed motors...lol. I believe I'm brushless fo life and I haven't even ran them yet.... :dude:

 

[KOZ]

Putting a rotor out of a 13.5 motor into a 10.5\4300 is flat out cheating,it's the windings in the motor can that make the difference between motors not the rotors..

As far as an AE car being JUNK, ae cars Dominated the Snowbirds in the 3 fastest classes...

 

[McLin]

KOZ is right, what you did was go from a 13.5 to a 4300 LOL

 

[Porksalot4L]

the best part of that was seeing that he got 11 out of 21 running a cheater motor classic

 

[parrott88]

Lap times are easy to explain... you went from a 13.5 to a 4300.

 

[cheatr71]

I don't get what you think is so funny, ya I cheated but that was only so I could run with them better, I was leading the B-main till somebody thought it should turn into a demo derby. The general consensus around southern wisconsin is that associated cars are junk and the best chassis are KSG, Leading edge, or someother chassis. I dont understand how these guys are running almost .5 second faster, the car is not that far off on handling. Any ways I don't plan on leaving the motors that way, it was just an experiment that paid off, but roar is rumored to be allowing the sintered rotor so i guess i'll buy that next.

 

[Porksalot4L]

cheatr71 i really hope you figure it out. maybe a local that you respect maybe will give you some help on the car and motor situation. i doubt the 10 guys that beat you are cheating but who knows. thats pretty bad tech