Dynamite 3835 1500Kv

[TheShaughnessy]

"thank you for writing it up Don. What causes the discrepancy in actual kv for two motors rated at the same kv? Same wind, same wire thickness , what gives ?"


Tolerance differences, a draggy bearing, end turns that didn't get pulled down as tightly as another motor, magnets that are stronger or weaker, maybe the magnets didn't get snugged down to the rotors shaft as tightly and they are closer to the stators teeth making a tighter air gap. This will make the kv a little lower but also increase the torque a little. If a motor gets to hot, the magnets can loose some of their strength and their pull to the stator will be reduced. This will lower the torque and raise the kv.

It really works out to be pretty danged close to the same for a given motor brand and wind. Like with the AQ 2030, I have checked maybe 25 motors and they all run between 1900 and about 1970. With the most of them being 1930-1960


This is with ONE motor brand and size, if that's what you meant. If your talking about between different brands, but with basically the same specs, then that's a whole different story.

exactly what I meant. Thank you!

[TheShaughnessy]

hey don't we already have a few threads for p limited rules???

I've found this thread very informative. I just went and checked and I have 6 motors 4 being the gold can variety that could benefit from this, assuming the magnet strength on the rotors wasn't too heavily compromised. After "de winding" one of the AQ motors I assumed it was impossible to fit that many wires back through the stator slots by hand.

Don when are you holding a class on how to rewind the motors? I'm ready and eager to learn. I've taken a course on electricity and magnetism but It really only focused on theory, i'd like to put some of that into practice, even if I still don't really understand it perfectly.

Ray, the front of the AQ gold cans is threaded on. I find two shafts, usually allen keys, that approximately fit into the cooling holes of the front plate. I then put those two shafts into a bench vice. Apply some heat to the front of the can to loosen up the glue, then line up the front plate with the shafts in the bench vise and turn the can. It takes quite a bit of force, you may need some sort of clamping device, something like an oil filter wrench might help.

[donhuff]

WOW Don, there is a wealth of great info here. thanks for sharing.

Thanks Steven.

I just wanted to share some info that I have figured out by tinkering with these motors. I wanted to understand how the work and why they run like they do.

I really thought that there would be more questions, because every time I explain one thing, it usually needs two or three more explanations, before the first one makes any sense! But I have found out in my older years that most people don't actually care why, something works, they just want it to work.

I kinda figured that someone would ask about kv, you know like what makes kv a set number and the motor wont go past that number.

[donhuff]

hey don't we already have a few threads for p limited rules???

I've found this thread very informative. I just went and checked and I have 6 motors 4 being the gold can variety that could benefit from this, assuming the magnet strength on the rotors wasn't too heavily compromised. After "de winding" one of the AQ motors I assumed it was impossible to fit that many wires back through the stator slots by hand.

Don when are you holding a class on how to rewind the motors? I'm ready and eager to learn. I've taken a course on electricity and magnetism but It really only focused on theory, i'd like to put some of that into practice, even if I still don't really understand it perfectly.

Ray, the front of the AQ gold cans is threaded on. I find two shafts, usually allen keys, that approximately fit into the cooling holes of the front plate. I then put those two shafts into a bench vice. Apply some heat to the front of the can to loosen up the glue, then line up the front plate with the shafts in the bench vise and turn the can. It takes quite a bit of force, you may need some sort of clamping device, something like an oil filter wrench might help.

Oh you can put a lot more wire back in them, if you have the patience!!! As I said before, the normal ones come with 30 strands, I bought some wire that was about the same diameter (there's is metric). And I was able to get 40 strands back in it! But that fine of a wire is easy to break and I stopped using it.

Can't get that much back in by "HAND". A lot of people think that these motors are machine wound, they are NOT. I don't think they can make a machine to do that, maybe, but I don't think so. Out runners on the other hand, are possible to be machine wound. But I doubt that many of them are as the cost of the machine would have to be pretty high.

Were having class right now, and the test will be in two weeks! Fail it and you loose your IMPBA card LOL. When/if you ever understand it "perfectly" please, tell me. I keep reading everything I can find on the subject, but so much of it doesn't really relate to what were doing.

All those engineering drawings of how stators are wound are down right bumfuzzeling. I had to unwind about 10 AQs before I finally figured out what was going on. Then I got a 3.5 half wind leopard and tried to figure it out. After a couple hours of hard cussing and pulling wire and drawing diagrams, I threw it a hard as I could into the woods behind the shop!!!!! Course I went and found it later, after I cooled off. I tried another one a little while back and did manage to get it that time, so I think I understand it now.

here are the tools that I now use to get the front off. I use to do it like you said. But I got to doing so many that I had to improve a little.

Bolt the wrench in the motor mount holes,then I slip the split sleeve over the can and chuck it in the lathe to hold it leaving the front half inch or so of the can exposed. Then heat it with a propane torch till it smokes the glue a little, and spin it off a round or two. Take it out, spray with water, and spin it the rest of the way, this keeps from messing up that last thread and making it hard to start back in. Most of the time this is easy peasy, but then sometimes you have to almost melt the aluminum before that damned glue will let go.

I wish I could find out what kind of solvent to use to soften or dissolve that glue with, AND not destroy the insulation on the stator. And NO, assytone don't work! After they get through winding, I think they dip it in the stuff as it has the wires locked in place in the stator slots. The AQ isn't to bad but the dyna 1500 is a bear to unwind. The only way I can get any of them out is with heat. Heat the stator and pull one slot...then repeat, 18 times. And then some of them still wont let go.

[donhuff]

The re-wind you did looks like the Hobbyking SK motor windings.

How do you unscrew the front plate on the gold motors?

All my burnt 2030 gold cans are 21 wire winds, go figure...

Ray,

Shag and I both answered this, but I forgot the pic. That's what happens when you get older.

DSC_5796.jpg

[TheShaughnessy]

funny you mention the PB 1500. I looked in one earlier today and noticed each individual slot had some adhesive on it. It also has a much bigger rotor so smaller stator and slots by the looks of it.

[ray schrauwen]

Still taking it all in Don. That's a lot to chew on....

Thanks Steven.

I just wanted to share some info that I have figured out by tinkering with these motors. I wanted to understand how the work and why they run like they do.

I really thought that there would be more questions, because every time I explain one thing, it usually needs two or three more explanations, before the first one makes any sense! But I have found out in my older years that most people don't actually care why, something works, they just want it to work.

I kinda figured that someone would ask about kv, you know like what makes kv a set number and the motor wont go past that number.

[donhuff]

funny you mention the PB 1500. I looked in one earlier today and noticed each individual slot had some adhesive on it. It also has a much bigger rotor so smaller stator and slots by the looks of it.

Mike,

You noticed the big rotor eh? That is one reason that the dynamite is so strong of a motor. I keep reading that a larger diameter rotor, makes more torque. I have no way to prove that, but it sounds reasonable, like a long stroke crank in a piston engine, makes people think that the engine makes more torque..

And your right that the stator is thinner radially, because of that big rotor. But the PB1500 has EXACTLY the same wire package as does the Aq2030. 30 strands, of .0105" I mean they look like they come from the same place, and they probably do! So wire content isn't everything, there has to be something else going on inside the PB to cause it to pull ahead of the AQ. We know the rotor is bigger around but I don't think that would be enough to make it that much stronger than the AQ, but that rotor diameter isn't the only reason for it's extra power...........

[TRUCKPULL]

Don

That is very interesting that the PB1500 and the Aq2030 have the same 30 strand of .0105 wire (2Y)
and yet the big difference in KV??

Larry

[jaike5]

Hi Don, great info put forth.

Would how much or how high the magnets are charged make the difference of the pb1500 and the aq 2030 ?

In Lehner motors the windings are on the outside of the inside of the can and the rotor has the magnet , how are these wound ?

I heard that Lehner doesn't charge the magnets until the motor is assembled , then charged is this a method of building motors , or is it even factual ?

Cheers, Jay.

[donhuff]

Don

That is very interesting that the PB1500 and the Aq2030 have the same 30 strand of .0105 wire (2Y)
and yet the big difference in KV??

Larry

Yes it is Larry,

Here are a few reasons that the PB has a lower kv

Larger diameter rotor (I guess since it has more weight/mass it takes more power to spin it)

Longer rotor/stator. The PBs parts are 2mm longer than the AQs, longer rotor always means a lower kv.

Tighter air gap between the rotor/stator. The tighter the gap, the more torque you make,the harder the motor coggs, the harder it coggs the lower the kv. Because of the way the PBs rotor is made, the diameter of the finished rotor, can be held to a tighter tolerance. Thus making it where they can get away with a tighter air gap. Also because of how it's made, they do not have to put a carbon or kevlar wrap around the rotor to help hold the magnets on. Again allowing the rotor to get a little closer to the stator teeth.

The rotor magnets are almost 2mm wider than on the AQ. They can do this because of the bigger diameter which equals more room around the rotor for magnets, and because of the way the magnets are held on to the rotor, this keeps there spacing perfect.

So, with bigger magnets I would guess that they would have to be stronger. Stronger magnet means more torque/horsepower and less KV.


And while your thinking about all this consider the TP 3630 (BTW the last two numbers in their motor designations is the length of the rotor magnets not the case length, just like Neu except Neu sez it in inches). But think about the 3630 2Y, same magnet length as the AQ, but it has a 5500Kv. Don't ask me why cause I have no idea. There is a lot more going on in those little motors than I understand, but I'm working on it.

[donhuff]

Hi Don, great info put forth.

Would how much or how high the magnets are charged make the difference of the pb1500 and the aq 2030 ?

In Lehner motors the windings are on the outside of the inside of the can and the rotor has the magnet , how are these wound ?

I heard that Lehner doesn't charge the magnets until the motor is assembled , then charged is this a method of building motors , or is it even factual ?

Cheers, Jay.

I'm not sure about that Jay. From what I have read, they can make really strong neo magnets. But what they put in our motors seems to be a good bit weaker. From what I read they are about mid way between strongest and weakest. I didn't understand this at first and thought that they should be using the strongest they could get. But reading further I found that the strongest are the easiest to loose there magnetism from heat, and naturally the weakest can take the most heat. So we get the stuff in the middle.

I do think what you say is right in a way as the PB has stronger magnets. But it's more a function of their size, and not their level of charging.


The Lehner's are what is called a slotless/toothless design. There is an iron outer ring called "back iron" around the windings, but no slots or teeth like a normal stator has. The copper is wound around something to get in it's approximate shape, then all three coils must be put into a form and pressed into shape. Then I think they encapsulate the coils in epoxy so they keep that shape during use, then the copper epoxy chunk is put inside that laminated iron ring, then all that is slid into the case. I have never held one in hand so this is coming from what I read.

No idea on the magnet charging Jay. I don't know why they would do it that way. The video I saw about magnet charging, the magnet had to be placed on this machine in a certain position to get the poles right. That would be hard to do with it in the motor.

[donhuff]

I was on the lehner website looking to see what the kv would be on their 2 wind motors. But on a 1930 which looks to be closest to what we are running. They didn't go down to a 2, the lowest was a 3D and it's kv was 6967kv. Divide that by 1.73 for a wye wind and you get 4027. Then if they did do a 2 wind I would expect it to be 1000 to 1500 higher than the 3 is so your almost at 6000 again.


But what caught my eye was something at the top of the page that stated "rpms are determined with 15* timing". Huuuummmmmmmmmm There's that dang timing thing again. And there default setting for their motors is Delta. ( BTW there is no such thing as rpmS, it's revolutions per minute, not revolutions per minuteS)


And remember when Thomas from MGM told us how to set up their escs. He said to use 10-15 degrees of timing. He did not say one wind needed 0 and the other needed 15.

[donhuff]

This article explains timing better than most I have read.


https://pphaneuf.github.io/rccars/ar...timing-theory/

[jaike5]

Hi Don,
The Lehner 1930 10T is 2090kv, 1930 11T is 1900 kv. they are 36mm x 54mm and weigh in at 230g. theses are loaded values.
Cheers, Jay.

[TRUCKPULL]

Don

Have you had the opportunity yet to look at a Dynamite 3831 - 6 pole 2000kv - 1.5D

Larry

[donhuff]

Yes I have Larry

[Speed3]

KV has to do with total turns.

Example a 12 slot 4pole that have 2y of winding has 24 total turns. If that motor have a 30mm rotor and it kV is 3000 rpm/v.

A 6 pole 18 slot motor that have a 2y winding configuration have 36 total turns. Let say this motor have a 30mm rotor it kV will be 2000 rpm/v if its rotor has the same total strength as the 4 pole motor above.

So 24 total turns gives 3000kv and 36 total turns give 2000kv.

You might notice a 2 pole would have significantly more turns to have the same kV as the 4 pole and 6 pole.

That is because it only have 3 slots. So it would take a 12 turn to get 2000kv with a 30mm rotor in the above cases.

[donhuff]

Speed,
I'm not sure of what your getting at there, with your turn count. This sounds more like an outrunner as they DO typically wrap the wire around each tooth individually. Most (but not all) inrunners do NOT do that, and instead wrap each "turn" around three teeth per turn, to make up one coil. If you take one strand of wire, from one leg, and run it through a 4 pole motor. It will go through only 4 slots before getting to it's other end.

The term "turns" refers to the number of times the wire bundle goes around a set of stator teeth, to make a coil.Then in a 4 pole there will be 2 "coils" per leg, and three legs (phase) so 6 coils for that motor. And with a 6 pole you have 3 coils per leg and 9 coils total.


I Wondered if there might be something to you total turn count vs kv idea so I went to the Lehner website and looked at the 1930 which seems to be the closest thing they have to the motors that we are discussing here. And a 12 turn like you suggested has a kv of 1742, that's pretty close but that is with a delta termination. Convert that to wye like the other motors were talking about, and you get 1005 kv.

To give you some food for thought. Kv is the point where a motor is "Making" as much voltage (back EMF), as you are putting in to it. That's why at peak unloaded RPM the motor has NO torque and thus NO horsepower.

[ray schrauwen]

Awesome day at brushless motor school.

Thanks Don.

[donhuff]

I have a bunch of stuff ready to take to the race this weekend. I'll show it and explain what I'm doing to anyone that's interested.


Notice in the picture that there are some papers with a stator drawn on them and the windings drawn in with three different colors. See also there are some sheets without the wires drawn. These are the "test sheets" so I can see if your listening or not. I told you there would be a test!


I also have an AQ motor that we can wire and run if we have time.

DSC_5798.jpg

[TRUCKPULL]

I wish I could be there, even without racing.
I could sit all weekend and learn how to wrap stators for brushless motors.
I use to do my own motors back in the brushed days, (slot cars)

Larry

[donhuff]

Don't know that I will have a lot of time to show it all during the race days. We are very busy usually racing, mechanicing, and helping with the retrieve boat. I should have a little more time this year as only two of my sons will be there racing, and the wife is not racing either.

Back in 1967 I rewound a couple of my slot car motors. I was 14 years old at that time, so they didn't turn out very pretty, but they did run ok best I remember. I remember shimming the magnets in with black electrical tape too.

[trigger]

Don, can you school us at the MI cup too. Mike and I will be there again and would love to be schooled over a beer or three.

[donhuff]

Sure, and maybe I'll be learned sumthing else by then.

only three??? You know I talk even slower the more beer I drink. How much time do you have?

[Doug Smock]

[ray schrauwen]

I have a bunch of stuff ready to take to the race this weekend. I'll show it and explain what I'm doing to anyone that's interested.


Notice in the picture that there are some papers with a stator drawn on them and the windings drawn in with three different colors. See also there are some sheets without the wires drawn. These are the "test sheets" so I can see if your listening or not. I told you there would be a test!


I also have an AQ motor that we can wire and run if we have time.

DSC_5798.jpg

You already soldered the wires for the windings. I thought that was done last.

Somebody video tape it and put it on YouTube or FB.

Are the green things actual stacks of stators? They almost look like plastic practicing formers.

[trigger]

Ha funny, Mike talks faster after a few beers, you talk slower, overall time will be unaffected.

[donhuff]

Yes Ray, the wires are soldered first at the "Y" connection. With the insulation being so hard to get off, and needing to be dunked in the molten lye solution, this would be to hard to do and keep short so you can bend it enough and keep it inside the back of the can.

By soldering the Y first, you can pull it down tight to the stator and lay it over sideways, and that is the very first step in the actual winding operation on a Y. On a Delta, you can leave the "start" end of the wires as is, and then strip and solder when finished along with the "finish" end wires. But you'll still need the needle.

Your probably also meaning that the wire bundles where they will be coming out of the motor, are soldered too. I do that to make a rigid "needle" to use while sewing the bundles through the slots. You can do it without soldering first if you use a very low wire count, and there is lots of room left over in the slots so that the wires go through easier. You can also use Ca glue on the wires to form a needle, and get decent results. But again if your packing the slots full, you will have a hard time getting them through the slots ON THE LAST TURN, loose wires will make a big mess and the ca needle usually breaks. It's aggravating and a waste but making the soldered needle but it is the best way I have found to do it. Also, it sometimes helps to put a slight bend in the tip of the needle, to make the point go to a corner of the slot and follow that corner, so it exits where you want it to and not pass through the middle of the wire already in the slot.

After completing the winding, then you cut the lead wires and needles off to as long as you like, and resolder.


Yes those are plastic stators. I have a friend with a 3d printer and he made those for me. They work great for practicing and demonstrating, and they don't scratch the insulation on the wire. If you thread the wires through a real stator very much. You'll end up chipping the insulation on it, and you don't want to do that more than you have to. When unwinding a stator, it's almost impossible to get all the wire out without chipping it a few times. I sure wish I had a solvent that worked.

[ray schrauwen]

Wow, awesome!!

A new question. I just received a chinesium motor from Fleabay. It's a $26 special. Can says 36mm x 70mm but you can dance in the front plate space.

Lets say I want to shorten the can to say 60mm, how can I shift the field coil since it's glued in? I wanted to trim the can down on my lathe to fit speccy classes.

It's possible to just machine it down but the front plate mounting screws might be real close...

2280kv and it's a Y wind. I don't know how accurate the 2280kv is.