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View Full Version : Tell me what makes your motors great? (long)


ianc
2008.12.25, 03:00 AM
I never liked the idea of just buying a motor, and have preferred to wind and assemble my own.

However, I find it difficult to get consistent results, even using consistent build and assembly techniques, and parts. I have bought similar (or the same) components, followed the same procedures, and gotten some screamers, and some dogs. What am I missing?

Lately I've been starting with the ATM M1 Endbell case. This offers ball bearings, and neo mags. A pretty solid basis.

For the armature, I've been buying either cheap 130 hobby motors from Radio Shack, or stage one X-Mod motors for.99 from Atomic Mods just for the arm to rewind. I know some will say these arms are inferior. Where then do I purchase better ones?

Once the arm is out of the donor motor, I unwind it, and wrap 35-45 turns with 30G motor wire. I work slowly and carefully to get a tight wind, but don't torture myself with pattern winding. I carefully polish the com with some very fine wet sand paper on a cylindrical mandrel.

For fitment, I measure the distance between the two inside seating surfaces of the can's ball bearings (assembled), and adjust the arm's freeplay to ~2 mm by moving the brass seating bearing on the arm shaft below the winds up or down on the shaft.

I'll lay a cap between positive and can, negative and can, and between pos and neg.

I'll typically bed the brushes by running 2 single cells dead, one after another. I do this dry, and not in water.

As I said before, sometimes I end up with screamers, and sometimes with dogs. My 934 goes like a scalded cat, but my GT40 has never been anything but asthmatic.

I've tested magnet strength by lifting various objects with great motors and poor ones assembled using these techniques, and they seem about equal in strength.

I've also wondered about the voltage delivered by the car's boards, but the GT40 was actually delivering about .2 volts more than the 934 to the motor.

Why then am I getting these strange results? What factor in the assembly am I missing that is obviously swinging the scales randomly from great to mediocre?

What has anyone observed in their own motor building experiments that enhanced or undermined performance? Please lay some insight on me or I may just give up and buy X-Speeds or Stock-R's. Thanks,

ianc

FastTRX
2008.12.25, 12:41 PM
While I have nothing to offer in the way of advice or an explanation I found your techniques interesting and have also concluded that not every motor/even engine is the same, just as you have.

I have had a very long following of the single cylinder ATV engine building world, and have seen alot of work by various well known engine builders. They all have their own techniques of course, but I have read cases like this many times over. It's interesting how the same processes followed the same exact way, using the same tools in the same place can create different engines. It's funny how the every engine turns out differently and has its own power characteristics in the way of where it builds power and how much.

I know electric motors don't have as many building variables to effect the performance like a gasoline engine does but its just ironic how its the same for both. How engine porting and valve work are done almost works the same as how the motor is wound and in what manner. Its just interesting to think about.

Sorry I have nothing to help...it was just something I wanted to point out. I have had very little experience in tuning a 130 can electric motor, but I have experimented with less than thrilling results.

EMU
2008.12.25, 03:37 PM
One thing that you didnt address was timing. I dont know if the RS or stage 1 armatures would have proper timing. This will make a pretty big difference.

There used to be a couple of sites where you could order motor supplies; armatures, cans, wire... but they are not around anymore. I believe they were mainly for the Xmod boom, but we reaped the benefits of having them around.

cowboysir
2008.12.25, 05:21 PM
Stage 1 xmod armatures could be modified to get better forward speed by adjusting the armature timing.(as EMU mentioned) This thread from xmodworld used to have some good pictures but you can still read through it and use mnm's timing angle chart to adjust those armatures you rewind.

http://www.xmodworld.com/modules.php?name=Forums&file=viewtopic&t=8192&postdays=0&postorder=asc&start=0

Hope it helps...

color01
2008.12.25, 06:36 PM
Pattern winding a couple armatures might get you more consistent results -- at the very least you'll be running a more scientific test. When you wind without any sort of pattern, you never really know if some of the magnetic fields generated by the coils are going to work with or against each other, and so there's a random experimental error that you can't really track down. You might've gotten such variations through a combination of several differences, including timing, winding tightness, commutator quality (I've gotten a motor with one dead pole on the comm before...), etc.

Timing is important for those cheapo armatures though, if you look at the armatures closely sometimes you'll get an armature with rather advanced timing, and then the next one will have retarded timing. Advanced is fine, retarded is, well.... retarded. :)

Flashsp-2
2008.12.25, 11:48 PM
Pattern winding and timing are both very important if you want to keep the motors consistent. Another issue which wasn't discussed was motor bearings. I have had the occasional brand new motor can arrive with some bad bearings, and this can seriously alter motor performance. The last thing would be the type of armature that you are using. Some of the older xmods armatures had a slightly larger diameter shaft, so if it requires any sort of force to push the armature through the motor bearings then you are going to get some binding issues, which again, will cause some serious problems. As for what makes my motors great, that's Top Secret :D

RedSXmodder
2008.12.26, 10:22 AM
Building, testing and tuning. I spend ALOT of time in the testing/tuning stages and I usually don't call a motor finished until its perfect for my standards at least. If a motor doesn't go the way I think it should I check these main points:

1) That the wire is properly soldered onto the tabs. If there isn't enough conducty, then the motor will barely run, or run slower than road grader on dope. Make sure you have the most conductivity by scraping the red/green/whatever color enamel off all sides of the winding wire. This ensures maxximum conductivity.

2) That there is not binding with the bearings/bushings or that the armature is in good shape (I've had bent armature shafts before). I simply set two razors on a level surface and let the armature free-roll. Then I check for imperfections. To see is your bearings are good, stick the armature into one of the bearings and spin it. It should spin for a few seconds. If it doesn't, lube the bearings and try again. If a bearing is faulty, then you'll have to change it.

3) The way the brushes sit on the commutator can also retard/advance timing. Also, if the brush gets mashed up or bent, and its not contacting the commutator like it did, then there won't be enough conductivity, and the motor won't run, or it will run reallly crappily.

Read into the tut that Cowboy posted. It helped me out lots. As for secrets, well thats really something I can't tell if I wanna continue selling motors, lol. Every builder has his tricks, lol!

Later,
RedSXmodder

ianc
2008.12.26, 02:02 PM
Gentlemen, thanks for the input.

I actually have experimented with timing before by removing the wire from the arm, then removing the piece containing the solder tabs, then superglueing it back on to advance it. Based on the diagram from the X-Mods link, I would say I got about 10 deg. I got some changes as listed, with less torque, more RPM, and a hotter running motor that eats up batteries quicker. Personally, I prefer the torque as it helps you accelerate quicker down the straight upon exiting the corner and that's where you pick up lots of time, assuming your corner speed is in the ball park.

I have not really made a habit of checking bearings, but I will do that, and I will also carefully check the as-built timing of a new arm when I go to wind it. Guess I just assumed these factors would be fairly consistent from the manufacturer, but that's probably a very bad assumption.

The idea of poor connectivity with the solder joints of the wires occurred to me, and I'm pretty careful about getting a good joint there.

Again, I appreciate the comments, but feel that perhaps you may be guarding your secrets a little too closely? I may be wrong, but I don't think there are actually that many people who race these things who will actually go to the trouble of trying to wind and build their own motors. It's just too easy to shell $20-30 to buy one, and certainly much less labor intensive...

Has anyone used the ATM M1 endbell cans before? I have seen that ATM offers springs of various tensions and wondered if anyone has tried them and what results you've obtained?

I don't particularly care for the brush design that comes with the M1, where the initial brush contact surface is a small finger which widens to a square. I've had some motors that worked well initially, but then drastically lost performance when the thin part of the brush has worn away and it doesn't seat properly on the com afterwards. I've taken to filing away the small finger then bedding the brush from there.

Any opinions regarding immersing the motor in water during this process? Does it accelerate the seating of the brushes? I wondered about it, but thought it might cause havoc with the bearings, particularly sealed ones.

Thanks again for the help and insight!

ianc

Felix2010
2008.12.26, 11:53 PM
ianc - Flash, color0, EMU, and RedSXmodder brought up most if not all of the important points in what determines a motor's performance. Just to reiterate some, from my personal experience with building custom Mini-Z motors:
1.) Making sure the commutator and the armature shaft & poles are balanced & not warped is important, which is something you already do ianc. Not that many shafts and their poles are warped, it would be a critical flaw. I know some guys used to balance the poles of the armature after winding, some still do by testing for balance and drilling-away some material from the offending pole(s). PN epoxy-balances some arms. The balancing of the arm after winding I have been told from my own personal motor advisor and grandmaster motor maker is that this final step of making sure the completed arm is perfectly balanced is not necessary as it makes minute-to-no real difference in performance. The critical thing is that the bare armature and comm are not warped.
2.) Brush contact with the commutator should be a high priority. Make sure the brushes are pushing against (seated on) the comm on both sides evenly (Not kock-eyed;));
They should have decent-to-good tension against the comm, but not too-too much. If you notice deeper than normal grooving in the comm after using the motor some then there's a culprit right thurr that can cause bad things to happen i.e.> poor performance. Recently I was testing/breaking-in an Atomic AD Stock with new brushes but the comm was grooved pretty bad from the original brushes having too much tension. Shortly into the motor break-in, all of a sudden the motor began pulling 3...4...6+ Amps and smoking.....
Speaking of brushes: I personally really dig the Atomic M1 cans a lot. The brush tension being able to be adjusted via swapping springs is purrty cool, and can change the motor's power output. On one Stock-R I have, I went from the stock silver (Soft) brush springs to gold (Hard, which are really medium since the next step up are Black springs which are Extra Hard:confused:) and the motor started pulling a couple tenths of an Amp more juice And Rpm's increased slightly along with torque - The motor was even punchier than the Stock-R is, well, stock. This can be handy if you want to make a high-RPM armature have a bit more punch.
Also the M1 cans' brushes are designed in an "L" shape for a reason - They slightly advance the motor's timing(Only for Mini-z's. Mini-z's need the motor to spin counter-clockwise for forward. On Xmods (Evo's at least) moving forward means the motor spins clockwise). The M1 brushes also are set 180 degrees from each other making for much more accurate, even pressure against the comm; On "regular" motors like PN & Kyosho, and the older Atomic/EGR motor cans the brushes have a "swingarm" type tension where each brush pushes against the comm at an angle. (Still, I do like and use many PN and older-Atomic motors - An good motor is a good motor:))
3.) Speaking of advanced/retarded timing, that's another key thing that can make a motor a screamer or a dud. For simplicity I usually just make sure the armature's comm is timed neutral. As I already mentioned, when used on an M1 can a neutral armature actually will be slightly advanced when spinning counter-clockwise due to the M1's "L" brushes.
4.) Motor cans with bearings should spin smooth and free. A crappy bushing or bearing will kill a fast motor and possibly your FETs, because with the added resistance the motor will pull more Amps. Usually without you knowing it if not checked for properly.
5.) A pattern wind is best. Time well spent IMHO.
6.) Usually a bad connection with the comm will make the motor not run at all. Make sure the enamel wire is stripped at the comm tabs and wrapped firmly.
I never tried water break-in. I almost always do break-ins using 1 Nimh AAA (1.5v) or 2 Nimh AAA's in series (3.0v). Or I use my MuchMore Motor Master at those settings. I run the motor for up to an hour depending on brush type (carbon,silver). I use comm drops to lube the comm during break-in. Only a dab'll do ya!! I don't use comm drops so much for racing though. The Voodoo drops work good for comm drops, even though they are more of a contact cleaner than a comm-lubricant. I don't think I ever did a totally-dry break-in. Maybe back in the day but I don't remember. I should give it a try just to see. But me thinks the heat from friction + sparking would be better subdued using some form of comm/brush lube. Keeps the comm from glazing. Nice:)
Sorry for the novel. Hope this helps

ianc
2008.12.27, 02:33 AM
Hi Felix, thanks for the novel! Let me add some thoughts to your novel then.

this final step of making sure the completed arm is perfectly balanced is not necessary as it makes minute-to-no real difference in performance. The critical thing is that the bare armature and comm are not warped.

Agreed. I believe in particular that the surface and concentricity of the comm (ie. consistent brush contact) is very important to performance. But how does one check it? To me, the greatest possible point of concern is the condition of the 3 petals of the comm. If they are bent or skewed slightly, I have not hit on a way of trueing them short of a lathe...

On one Stock-R I have, I went from the stock silver (Soft) brush springs to gold (Hard, which are really medium since the next step up are Black springs which are Extra Hard)

What is your opinion on the difference in comm wear you're experiencing with the harder springs? Do you typically mount the spring above or below the pigtail? Do you rotate them (turn upside down) periodically? I do this when I can hear that reverse is sounding better than forward...

the M1 cans' brushes are designed in an "L" shape for a reason - They slightly advance the motor's timing

Not more than a degree or two I shouldn't think, plus that will go away as the brushes wear...

Still, I do like and use many PN and older-Atomic motors

Me too! I'm running a couple of the older-style cans right now; hadda drill 'em both. I agree on the superiority of the M1's basic design, but to me, a distinct performance (not longevity) advantage is not demonstrated over the earlier brush mounting method. Also, those damned tabs on the M1's side to hold down the endbell! Always way too short! @^%^$#@

I usually just make sure the armature's comm is timed neutral

Yeah, I think if it was too far out I'd notice, but I haven't made a habit of checking it. I would tend to think something <3 deg would have minimal impact, but 10-12 would be noticeable?

5.) A pattern wind is best. Time well spent IMHO.

Good lord! I just can't take it! I'm already sweating and cursing after doing a non-pattern 45. My hands hurt too much for that. I'll not do it! Careful yes, painstakingly pattern, no!:D

ianc

Felix2010
2008.12.28, 01:56 PM
Hi ianc,

- For the comm, you are correct. The only way I know of to true a comm is via a lathe. I had someone do this for me on a handwound armature I had with a slightly out-of-true comm, he shaved just a hair off the top layer of the comm's "petals".:D I would have to say if the comm is bad enough out-of-true, and you don't have access to a 130-motor comm lathe, then replace it with another comm from another armature.

- I haven't yet used the Stock-R I modified enough to see if there is any adverse comm wear from the harder M1 brushes. I am not sure what you mean by "Do I mount the spring above or below the pigtail?". If you mean how do I have the spring resting on the back of the brush, then I would say from my experience it doesn't matter. If I have interpreted your question wrong please explain further if you can.
If by "rotate" you mean do I "flip" the brushes periodically, then no I do not. If by "rotate" you mean do I just swap the positive+negative side brushes once in a while, I haven't done that either. You could try it though.
Even though the shape of brushes begins to fade after wear, for Mini-Z applications the brushes are still meant to only be installed in the M1 can in the way Atomic has them. That is unless you want to make the car faster in reverse, like for Xmod applications. Then you could "flip" the brushes for faster "forward" direction spinning clockwise.

- The M1 brushes do only slightly-advance the timing, you are right. But nevertheless the motor is advanced counter-clockwise. Albeit ever-so-slightly.:)

- The amount of the advantage gained from the M1 can I can't say. I agree that the simpler, older Atomic motors are very effective. To see the difference between a properly tuned M1 motor and an "old-style" Atomic motor both with the exact same armature you would need a Motor Master. The difference in performance would be very subtle. And I too can never get the M1 endbell tabs to crimp-down the endbell securely. I just do my best to try and make sure the endbell won't come off.:eek:

- It's hard for me to say how big of an impact advancing the timing makes on all armatures, and at what range of degree the timing needs to be advanced to see positive results. With the size of these armatures being so small, even a tiny movement of the comm can be enough to get a result. A teensy-tiny turn of the comm can be upwards of 10, even 15-20 degrees, so I don't suspect I would even notice a 1-3 degree advance on these size armatures. But to answer your question, does advancing the timing make a difference?> Yes. Might you need a Motor Master to see the increase in Rpm's?> Yes.:)

- As my Motor Grandmaster teacher tells me, cramping of your hand after EACH POLE is a sign your doing it right. I guess you have to be a lil' masochistic to be a pro motor winder.;)
Keep the wire tight, and make sure you wrap the wire in the same direction around each pole, and that shouldn't be too shabby. (Note: I can't make good pattern winds either. But if you can, a pattern is better than a non-pattern.)

ianc
2008.12.30, 04:57 PM
Thanks for the tips Felix.

Cleaning and oiling the bearings seems to help, but that is more a maintenance-type thing.

I like to remove the magnets from the can and insert the arm, then put the end bell on and spin the shaft. I guess if the bearings are good, but not true to the axis of the arm, you can get some binding issues, so spinning the arm with the can assembled (minus magnets) seems like a good test.

One other thing: those little plastic spacers that go on the ends of the arm: if you use these, make sure their outer diameter is not larger than the bearing's inside race. If they contact the outer (stationary) race, you'll get some friction there.

I had not thought previously of the advance obtained by the design of the M1's brushes. I have never bought an ATM motor, just the cans, so the brushes don't come installed, and the advance factor didn't occur to me.

I still like filing the finger off the brushes for reliability reasons, but the X-Mod arms are easy to advance slightly as they don't seem to have a tab and slot mechanism to hold the com in place like some other arms. Just carefully grab them with a needle nose and rotate a little bit CCW,

ianc

Felix2010
2008.12.30, 11:00 PM
Thanks for the tips Felix.

Cleaning and oiling the bearings seems to help, but that is more a maintenance-type thing.

I like to remove the magnets from the can and insert the arm, then put the end bell on and spin the shaft. I guess if the bearings are good, but not true to the axis of the arm, you can get some binding issues, so spinning the arm with the can assembled (minus magnets) seems like a good test.


- Cleaning & oiling the bearings does indeed help. Sometimes I like to take an empty motor can (sans magnets or with 'em still in, doesn't much matter) and dip the can into motor cleaner/degreaser/solvent. I also pop the bearing out the endbell and soak that bearing too. I like to run my cars' wheel & chassis bearings "dry" a lot, I find the performance increase is very good. Some people don't like the noise of dry bearings (The car will run louder without any lube to dull the noise of the spinning bearings); Some people don't like to risk wearing-out their bearings prematurely. My thing is, even the thinnest bearing lube I have, which is like water, can create drag on bearings; Just a tiny amount of drag, yes, but run dry bearings a little while and soon you'll want all your cars runnin' dry.:) Anyway, back to the motor - Most sealed motor bearings are grease-lubed and cleaning the grease out the motor can's bearings helps the armature spin easier. You can choose to run the motor bearings dry, but a tiny bit of a good thin lube is a good thing for motor bearings since motors get a lot hotter during a run than the bearings on a Mini-Z chassis do.

- Spinning the armature with the can assembled minus magnets is a great thing to do to check for binding and poor bearings. Clean the motor's bearings like I said above and you should see the armature spin even faster and smoother with less drag.

One other thing: those little plastic spacers that go on the ends of the arm: if you use these, make sure their outer diameter is not larger than the bearing's inside race. If they contact the outer (stationary) race, you'll get some friction there.

- Another good thing to check for.

I had not thought previously of the advance obtained by the design of the M1's brushes. I have never bought an ATM motor, just the cans, so the brushes don't come installed, and the advance factor didn't occur to me.

I still like filing the finger off the brushes for reliability reasons, but the X-Mod arms are easy to advance slightly as they don't seem to have a tab and slot mechanism to hold the com in place like some other arms. Just carefully grab them with a needle nose and rotate a little bit CCW,


- If you haven't purchased a Stock-R or Chili I understand why you might not have noticed all the M1 subtleties then. If you look at the M1's endbell, on the back there's a picture of how the brushes should be installed: One side (either pos or neg) with the "lip" on the top, the other side with the lip on the bottom, so the brushes kind of "cup" around the comm.

Again, hope I offered some tips to help get the most performance out of your motors.

ianc
2008.12.31, 05:21 PM
If you look at the M1's endbell, on the back there's a picture of how the brushes should be installed

You know, I had another look at this last nite, and when I looked at a couple of my older motors, I had not noticed the diagram and installed the brushes sideways! ie., so that the long side of the finger was perpendicular to the comm's axis, rather than parallel to it. I installed a couple of new brushes (the correct way) in one and broke them in with a couple cells. Haven't had a chance to test it yet, but it surely did spin up nicely for just one cell!

That's definitely an eye-opener, so thanks for that!

ianc

ianc
2008.12.31, 05:33 PM
Here's one more question while I'm at it: magnets.

Sometimes you get the situation where you have an unmarked set of magnets and you install them in the can and the motor will end up spinning backwards from what is expected when it's wired correctly. Is only one magnet responsible for this reversal, or do both need to be installed incorrectly?

Some magnets have markings along the top to indicate that side is supposed to be 'out', but some don't. I guess it must have to do with the S & N poles of the magnets. What happens if one magnet is installed correctly, but the other is upside down?

Is there a way to test for the correct orientation of both magnets before installing them in the can?

Great thread! I'm getting a lot out of it,

ianc

Felix2010
2009.01.02, 06:19 PM
Here's one more question while I'm at it: magnets.

Sometimes you get the situation where you have an unmarked set of magnets and you install them in the can and the motor will end up spinning backwards from what is expected when it's wired correctly. Is only one magnet responsible for this reversal, or do both need to be installed incorrectly?

Some magnets have markings along the top to indicate that side is supposed to be 'out', but some don't. I guess it must have to do with the S & N poles of the magnets. What happens if one magnet is installed correctly, but the other is upside down?

Is there a way to test for the correct orientation of both magnets before installing them in the can?

Great thread! I'm getting a lot out of it,

ianc

Magnets have been a topic of discussion amongst me and my motor guys for a long time. The ultimate consensus was that the way the magnets are installed in the motor can does not matter. The one exception I am not sure if this assumption is correct though would be if an armature is advanced for a particular direction, either clockwise or CCW.

The magnets for our 130 motor cans have the two poles on either of the large flat curved sides. These are the magnet's "top" and "bottom": One side is North (or positive, whatever the correct term is for magnets); The other side is South. The important point is you must have two of the opposite magnet to make a motor. This means that one magnet should have the positive side on the inside curve of the magnet, and the other should have the negative side of the magnet on the inside of the curve of the magnet. The magnets should attract each other when either when both curves are facing towards each other like this "()", or when they are facing each other like this ")(". As long as the magnets you are using are polar opposites of each other, you're good.

As long the the armature you're using is timed neutral, then the motor should spin the same speed in both directions. Just solder the positive and negative motor wires to the brush sides that correspond to forward and reverse on your car.

If you are using an advanced-timed armature, then to be honest, I'm really not sure if the magnet orientation matters or not. My mind overheats every time I try to think about this actually.

ianc
2009.01.02, 10:20 PM
Magnets have been a topic of discussion amongst me and my motor guys for a long time. The ultimate consensus was that the way the magnets are installed in the motor can does not matter.

Ya know, I'm gonna have to disagree on this one. I know that the magnets are marked for a reason, and sometimes I get a motor spinning backward for no apparent reason; the only thing it could be is the orientation of the magnets.

I have done a little more searching on it however, and I'm now convinced that it is not which side of the magnet is placed 'up' in the can, but rather how they're placed from side-to-side. I've seen magnets where only one of the two was marked, and I think it matters whether this magnet is placed on the right or the left of the can (pos or neg brush side).

If you look at the open end of the motor can (brush side up), I believe the marked magnet should go on the right, which would place it on the same side of the can as the positive brush. Just a theory at this point, but I'm planning to put together another motor later tonite and I'll test it out and report back.

Still don't know a way to test them if they're not marked however...

ianc

Edited to change the text above and also to say that I did test this theory on a motor last nite with a pair of magnets of which only one was marked red and it did work. YMMV...

Felix2010
2009.01.04, 12:41 AM
PN came out with their Nascar 102mm motor mount a while back. With this mount the side the motor sits on is reversed - Instead of the the diff gear and pinion being on the passenger-side of the chassis (US-car passenger side), the diff gear and motor are switched around to the driver's side. This is because on Nascar race tracks the cars run counter-clockwise instead of normal Mini-Z racing which is almost always conducted clockwise. The thing is, if you turn the motor around on a Z then "forward" is now "reverse". So PN simply said to connect the motor wire leads to the chassis in reverse. PN motors (And all machine motors I know of) are timed neutral and spin at the same RPM's & power both clockwise and counter-clockwise, so swapping the power leads doesn't make any power or speed difference. Since the armature inside a motor doesn't have a fixed polarity (The poles only magnetize when current is introduced) reversing the powering of the motor brushes reverses the polarity of the poles on the armature inside the motor, thus changing the armature's direction. This is the simpler way to make a motor spin in the desired direction, should the positive marked motor wire hooked up to a positive power source terminal/negative wire to the negative terminal not achieve the desired motion. The same thing/same effect would be to swap the sides that the positive-marked magnet and the negative magnet are inside the motor can. These magnets have fixed poles, so by swapping the sides they are on, and then powering the motor as it normally would be (positive lead to positive power terminal, negative to negative power terminal), the armature will spin in the reverse direction.

I hope you could follow that OK, sorry again for the long explanation.

Could you tell me what "YMMV" stands for?

EMU
2009.01.04, 01:03 AM
Could you tell me what "YMMV" stands for?Your Mileage May Vary :p

I think that motors that I have used for Nascar, Speedy 05 and 07, run slightly faster on the Nascar mount than with the standard mount. They seem to have a slightly faster acceleration, and higher top speed.

Take a motor, put the red wire on the + end of a fully charged AAA, black wire on - end of the cell. Listen to the how it sounds, and the length of time it takes to reach its max revs. Then switch the wires and do the same test. Most motors will spin faster and accelerate faster in reverse...

Ibrake Ifry
2009.01.04, 10:18 PM
Your Mileage May Vary :p

I think that motors that I have used for Nascar, Speedy 05 and 07, run slightly faster on the Nascar mount than with the standard mount. They seem to have a slightly faster acceleration, and higher top speed.

Take a motor, put the red wire on the + end of a fully charged AAA, black wire on - end of the cell. Listen to the how it sounds, and the length of time it takes to reach its max revs. Then switch the wires and do the same test. Most motors will spin faster and accelerate faster in reverse...

I totally agree EMU! You can definitely hear the sound of a motor that has non neutral timing. The only thing to be wary of is that if a motor is well broken in, spinning in one direction, initially it might be slower in reverse. Every time i buy a motor regardless of brand i always open it up after break in to polish the comm and clean it out. While i am doing this i have encountered a lot of motors that are not timed properly. The worst culprit was an atomic stock motor which had its timing retarded by at least 5-10 degrees(hard to tell at this scale:D) Retarding the timing does effectively lower the power of the motor and RPMs so i think that this is one of the biggest factors separating same brand/model motor performance from one another.
On the other hand, advancing timing also lowers the power of the motor but it increase RPM's
If i would have not touched that atomic motor and put it in a Nascar it would have looked modified :eek:

XMDrifter
2009.01.05, 01:40 PM
10 degrees of advanced timing seems to be the sweet spot on motors.
i've tested a few spiral arms that i made, one spiraling left and one spiraling right, and both had advanced timing in opposite directions. one i run in my xmod (the motors in xmods spin opposite most mini-z's) and the other, i'm saving so i can use it in a mini-z (if i ever come up with the money to buy it)
i don't bother with manufactured motors since i can probably make an identical one.

ianc
2009.01.07, 10:25 AM
10 degrees of advanced timing seems to be the sweet spot on motors.

I just have never had good results with advancing the timing on these motors, although I suppose it depends on the track you're running on. For small to medium sized tracks, I should think you want the torque.

Example: My friend brought over one of the old Tamiya speed testers to my house last Mon before our run. He put his Mazda on there with an ATM Stock R, (which, as we have already discussed, is somewhat advanced already due to the brushes since it runs the M1 endbell), and was crowing about the 30 KM\hr he was getting. My 934 could only manage 19 Km\hr. However, I have to think my motor was much torquier than his (no advance) because I could still easily outaccelerate him on the straights. Our track basically takes up both slots of a two-car garage, with perhaps 10-12 ft straights, and I would rather have the torque on this size track for certain.

For a non-advanced motor, I don't think you should see a difference in speed from fwd to rev, all other things being equal. It's just that since you run 99% of the time in fwd, the fwd side of the brushes gets eaten up faster, and hence is less efficient. I think you'll only see this on motors with some time on them. A newly broken-in motor should be faster in fwd.

XMDrifter, what is a spiral wind? I believe I've heard of this, but don't know exactly what it is? Can you share your techniques?

Great thread,

ianc

Ibrake Ifry
2009.01.08, 12:14 AM
I totally agree that about 10 degrees is a sweet spot on these motors. Just to give you an idea, i advanced a speedy05bb(that i don't use since its illegal) about ten degrees and checked it out on a much more motor checker. before i advanced it the motor spun around 28,000 rpms. Afterwards it spun 38,000 rpms. 10k rpms is huge although that is without a load. Since you are reducing bottom end torque by advancing i have found that gearing down a pinion makes the motor have the same bottom end (if not greater!) but a nicer top end.
Ianc: i totally agree torque is everything on a tight track(if you can put it down!):D and you should gear according to the layout. Advancing the timing of a motor just changes the characteristics of a motor and the sweet spot of its gearing so take that into consideration. Beside atomic stock R's are darn near modified but if geared improperly any motor can seem crappy

Felix2010
2009.01.08, 10:30 AM
Your Mileage May Vary :p


Thanks EMU. With these 130-class motors, Your milage may vary, for sure.:D Motor tuning drives me crazy sometimes.

EMU - Your experience with the Speedy 05/07's spinning faster in reverse, Have you had a chance to open up either motor and check the comm's timing? From my motor tuning experience, if a motor spins faster in one direction then I first suspect the comm timing is not neutral. A careful look might be necessary - These motors are so small that sometimes a motor can look like it's timed neutral but be off a few degrees, which just might be enough to get better results in reverse. Of course, I could be wrong - What are you guys listening to me for anyways?:eek::D

Another thing with motors is during break-in, and when used in general, brush debris can interfere with motor performance. I see big jumps in Rpm's & Amp-draws whenever I am breaking-in a new motor or when testing motors sometimes that have some decent wear on the comm. This is because of the brushes changing their seating on the comm and from carbon and/or silver brush "flakes" sticking to the brushes and in the comm crevasses.

atallfunguy
2009.01.08, 10:32 AM
Keep in mind, you are not alone in your motor building have different results.

In 2008 We started racing the PN 70T Stock. These motors are built with a machine. so they should be very precise. We have a dyno at the shop and have dyno'ed more than 30 of these and have found motors with over 25,000 rpm and under 19,000. We were keeping the current and everything the same just pulling out 1 motor and dropping another 1 in.
In stock racing these motor are Miles apart.

Now we are racing the USA motors from Atomic and have found the same thing. I have 5 of these motors and only 1 good one.

--------------------------------------------------------------------------
This is official PNWC 2008 Stock Class motor.

Designed for: MR01, MR015, MR02, F1 and AWD

Designed for stock, no modification to the PCB or external turbo is required.

Stats:
- 70 turn balanced armature
- New endbell design for increased cooling
- High performance carbon brushes

Performance no load
Speed = 21,785 RPM +/- 1500
Current = 0.481 AMP

Flashsp-2
2009.01.08, 01:12 PM
These motors are built with a machine. so they should be very precise.

I have definitely had a different experience than what you are saying. Pattern wound motors are always much closer to each other than machine wound, given that hand winding uses a very similar amount of wire length on each segment, and each full armature.

atallfunguy
2009.01.08, 02:29 PM
I have definitely had a different experience than what you are saying. Pattern wound motors are always much closer to each other than machine wound, given that hand winding uses a very similar amount of wire length on each segment, and each full armature.

Good Info.. I have no knowledge of anything related to motor building. Your the man on this topic.

I was just thinking that a machine would use the exact same amount of wire each motor. from my dyno testing on 30+ Pn motors and your statement above this is not the case.

BTW Flash, What's the shipping charge on 2 motors from Japan to the USA ?

Ibrake Ifry
2009.01.11, 11:58 PM
I definately agree with Flash. You should see some of his work and then compare it to your motors. A machine wound armature looks like a 3 year old wound it up compared to flash. The biggest difference is that a hand wound armature evenly wraps the wire neatly to promote a stronger magnetic field increasing torque and rpms.

ianc
2009.01.12, 04:38 PM
i totally agree torque is everything on a tight track(if you can put it down!) and you should gear according to the layout. Advancing the timing of a motor just changes the characteristics of a motor and the sweet spot of its gearing so take that into consideration.

yeah, but I can't see the benefit. If you have less torque down low, you have to gear lower to compensate, whereas with a torquier motor, you can gear higher and get comparable performance, but with less heat and longer battery life, so why bother?

Also, is no one going to enlighten me as to what exactly a spiral wind is?

ianc

ianc
2009.01.13, 10:21 AM
Also Felix, I am now a believer in dry bearings! I took a motor apart recently that I had added some oil the the bearings on and saw that the oil had been flung around inside the can and was in danger of fouling the brushes. Wanting to try your suggestion, I dunked the can and endbell in carburetor cleaner and swished the bearings around a bit. You should have seen the crud in the carb cleaner! Afterwards, the arm spun like a top!

I must admit I was a bit skeptical about this due to fears about bearing wear, but I've even begun to do it to wheel bearings as well...

ianc

Felix2010
2009.01.15, 07:27 PM
From what I've seen, torque is not largely affected by slight timing advance. High-torque motors, like those that use Neo-magnets and motors with large wind-counts paired with fat commutators, can benefit greatly from advancing the comm timing. I don't have actual torque figures, but real world tests in my cars have not shown noticeable power loss on the track. There are exceptions of course when motor advancing really isn't necessary, like motors that are speed-demons with loads of torque too, such as a Plasmatomic (Mine spins @63k+ @4.8v, this thing is no joke) or maybe a custom wind in the 21-28t range (w/Neos). Advancing the timing wouldn't hurt I guess, but an 80k motor for RCP racing?:cool: Also, motors with normal (ferrite) magnets will have their torque affected much more with their armature's timing advanced because the weaker ferrite magnets don't create the large amount of torque that Neos create.
Maybe if you go too far with the comm advance, timing could cause some bad effect. Or advancing the timing on a weak-torque motor might not be worthwhile. It's a trial and error technique, since no two motors are the same.
Advanced timing can actually smooth-out(don't worry,only subtly) a real "torquey" motor. I tend to mash the throttle, and less crankin' torque off the initial pull can help keep wheels grounded, like an MR02. Again, it depends on the motor.
On small tracks, it is hard to really gain an edge between a, say, stock required motor like a 70t. But go to a larger track, up to like the Kenon track, or the layout for the PNWC in Vegas, an "advanced/tuned" 70t will have the edge vs. a non-tuned 70t . The advanced motor will be faster on the top-end, and torque should still be comparable to the neutral-timed motor. There should be no need to gear-down a properly advanced motor. Even try gearing-up an advanced-tuned motor for greater speed, if you can handle it.:D

Ibrake Ifry
2009.01.16, 12:37 AM
Just to clarify some things. I agree that advancing timing on motors with neo's have very little effect on the torque of the motor since they already have gobbs. In fact the advance almost makes it feel like it has more since it spins up higher. The major area on ferrite magnet motors, where the timing advance is felt, is on the very low end. I suggested previously to gear down because the motor will actually have much more torque throughout the powerband and still go faster. For example, i toyed with an old speedy 05 that i geared at 10/43. After i advanced the timing i dropped down to a 9/43 and the motor had more top speed, and torque. As far as temperatures, whenever gearing down a motor, you will always lose some degrees since it stays in the low revving, somewhat shorted out state(stall), for shorter periods of time. In fact with these motors temperature doesn't matter much unless you are getting to a point where the motor gets so hot it affects the magnets. now advancing the timing will effect the magnetic field at stall so with the proper test equipment you will see decreases in stall torque but what really matters is torque multiplication. Think honda civic revving to 10k with cams and short gears. the engine has no torque but has a nice horsepower. This is kind of the same concept here with advancing the timing to a small degree.

ianc
2009.01.16, 12:32 PM
OK, let me ask a hypothetical question here on a motor I have.

I've got a set of just stupidly strong neo mags that I got from a fellow on this board named Draconius some years ago. Waaaaaay stronger than the standard ATM neos.

I tried these mags in a bb can with a 45 turn non-advanced arm. The motor made tons of torque (not a lot of RPM), but the trouble was that the magnets are so strong that the 45 turn arm couldn't develop enough starting torque to overcome them. If you pushed the car forward, it would run, but nailing the throttle from a standstill just left the car sitting.

Next I tried a 70 turn wind in it. That will always start from rest, but a lot of the speed of the motor is gone. It's got decent punch from start, but the motor just runs out of breath almost immediately and has no speed.

Should I advance the timing? Experiment with something between 45 and 70? Just scrap the magnets altogether? Any other suggestions? Thanks,

ianc

Felix2010
2009.01.16, 01:03 PM
I had a set of crazy-strong neo magnets that I got a long time ago. They were from a 15t silver-wire motor made by MiniZ Workshop, a website that used to be around during the Xmod days. I still have the armature, I took apart the motor and took out the Neos - They were golden-color, and probably 1.5x the thickness of the Atomic Neos. These really were stupidly-strong.
The 15t silver-wire motor had the same problem you're talking about ianc: The motor didn't have the power to start from a stall, you needed to give the motor/car a push to start the motor moving.
I think I gave a friend of mine the magnets to mess around with. I could not get the super-strong Neos to work with anything I had. They just weren't useful. As you said, the power these magnets have is just too great to produce worthwhile Rpms. I do not think advancing the timing on an armature will help in the way you want it to. As Ibrake Ifry explained, the timing-advance will have its largest effect on a motor's torque at stall, and on the very-low end of the Rpm range. Advancing the timing might make it even harder for the armature to start spinning.

BTW - I'm glad you like the "dry" bearing trick. It can make a very big difference in drivetrain friction, esp. with the MA010.:)

Ibrake Ifry
2009.01.17, 01:32 AM
a 70 turn with neo mags would rev ridiculously low. Its actually somewhat better for these motors to rev up a little bit since they draw less current. Advancing the timing might help a bit but not nearly enough to smooth the motor out. as far as the 45 turn i have never had any problems running motors with these magnets. I used to buy the golden neo mags from minizworkshop too. I used them to make hybrid plasma dash motors :) Neo magnets do add somewhat of load to the armature though which is why it reduces revs and increase amps. I guess its a possibility that the 45 turn is just not very efficient and that's whats causing the problem?

Felix2010
2009.01.18, 05:10 AM
I used to buy the golden neo mags from minizworkshop too. I used them to make hybrid plasma dash motors :)
Hybrid-Plasma Dash motors using the extra-thick Neos from MZW? Holy christ, I should have thought of that.:) What did you use with the extra-thick MZW Neo -> One regular Neo(ATM,PN), or a black/ferrite magnet? I like the "hybrid magnet" technique myself also, it is great for taming some beast armatures. Keeps the torque more tame off the mark.

Ianc - A spiral armature or wind refers to the shape of the armature's 3 poles, not the windings. Instead of having the curved outside edge of the 3 poles square in shape, the curved outer-edge of the poles are parallelogram-shaped. Spiral armature motors typically create higher Rpm's and less low-end torque. Here's a pic of a spiral arm. This happens to be a TSM 30t single-slotted spiral armature:) :

XMDrifter
2009.02.03, 09:09 PM
XMDrifter, what is a spiral wind? I believe I've heard of this, but don't know exactly what it is? Can you share your techniques?

Great thread,

ianc

sorry for not replying, i've been dormant for a while.
spiral is just because of the armature:
a regular straight armature look like this:
http://freestylexmods.com/projects/Raymond/Pics/Motor.jpg
a spiral armature looks like this:
http://www.biline.ca/Xmods/Reviews/spree/sparm.jpg

that's the only difference, but since the armature spirals, it spreads out the magnetic feild of the coils, allowin the motor to be smoother as well as affecting the timing

if you take PN handwound armatures, and test several of them, they should all be around the same rpm and torque, since they are handwound in a pattern, meaning that there's nearly exactly the same amount of wire on each armature. possibly exact to millimeters