3573 replies to this topic

[Jeff Buyer]

John,

We finally had a chance to race the 5-pole Kemtron you rewound for me some time ago. It is a rocket compared to my stock Kemtrons. Thanks again for all you do.

JB

[havlicek]

Hi Jeff,

I honestly don't know what I did with that motor as 5-poles are a huge guess for me. In any case, I'm tickled it worked out OK (however I managed that???) because it's always a pleasure working for you.

-john

[havlicek]

I got a couple of test motors from a Blogger to play with. These are trial motors for what I think will be "homeset" type cars, and they came with those extremely stout solid neos with the nickle plating that look identical to the Emovendos and similar that the drag guys are using. The stock arms were almost completely magnet bound and I could barely get them to turn over at 5.5V by spinning them by hand...drawing less than half an amp. I rewound a Hawk arm with the stock com using #28 wire, keeping the air gap stock and using the stock Hawk com. I also fitted a Hawk endbell. The motor runs well, but a little weird (I'm guessing that has something to do with how wide the brushes are for the com diameter as Swiss worked out???).

Second test, I figured I'd do something different. I used a eurosport arm blank that cleans-up at .480" for a much larger "hole" with a Bugenis com and did a #26 wind (.114 ohms). Even with the gigantic airgap (magnet ID is around .530+", arm is .480"), the motor starts and stops like it has a supercharger and disc brakes, revs like a champ but now gets pretty warm. I may experiment further with brushes after the long thread here about that stuff. I may also install taller spring towers so I can put some Camen springs on there (right now, I'm using Mura mediums) and see if any of that improves things. My whole idea was to see if these magnets and a pretty hot wind (pretty much in eurosports territory) could be made to live together as a road racing (as opposed to drag) motor...a "eurosports-on-the-cheap" kinda thing. So far, it's not looking too promising.

-john

[Coal Train]

Good luck John
I am a drag racer and I am the one who has the 12 segment Neo magnets for the open/grp7 motors I also make the 6 segment Neo magnets for the c-cans.
I don't know if you'll be able to over come the heat problem so they can be used in road racing but being used as drag motors isn't a problem .
On the drag side of things we can't go too far with the air gap because of the torque needed to get out of the hole quick and the amount of glue needed the whole length of the strip.
But if you could find the happy place so the motor doesn't get hot then you will difinately have a motor that will crush any other motor thats running the same arm.
But then it falls back on to the ru;les for your roundy class , I'm sure there will be a protest if one guy is owning the track with a neo motor and all the rest are 100 laps behind .

John medium springs are a good spring I personaly have try'ed the super heavy duty , heavy springs and mediums and so far I have found the Camen regular springs to be
the spring for my happy medium.
But in saying that I have found excelent results with Champion medium springs but to find a brand new set of them is like looking for hens teeth.
I'm keenly interested in your test results as i've been testing theese neo set ups in drag cars since 2009 and one of my neo AA/FC has the un-official record here in Australia , .4441 @ 126mph
So far on the market there are your basic single mags such as emovendo , Kennon and I'm sure ProSlot usses them in there velosoraptor motors and then you have the Quads that are mainly
used in the hawk and euro cans and then up to the 6 segments for the c-cans then up to my 10 and 12 mags for open set ups.








Robert K

[havlicek]

Hi Robert,

Neat motors! I think I made too many changes on the second motor and should have stayed with the #28 wind since the first one ran OK but I think the Hawk com was the main problem. I'll tinker some more as I get motivated for sure and thanks for the pictures!

-john

[Coal Train]

I think the hawk comm is too small , I think you get too much over lap arching going on but I have been known to be wrong sometimes.
What I would like to try is a pure silver comm with pure silver wire .
I know youve been doing this for a lot longer than me so I'm going to ask , have you try'ed this before ?

I spoke to Bill through e-mail and he said that there's no need for the silver com or the wire and if I had thought it through
and he's right I hadn't thought it through .
I have no problem getting materials 18 inchers of pure silver rod will cost around $300 and the wire is cheaper .
My thinking is the neo magnets over power the coils so what if the coils can energize and de-energize a lot quicker
will this help over come the problem of the magnets being stronger than the coils ?
I'de love to know what and where i can get the machine to make coms so I could try this out .

[havlicek]

Hi Robert,

I think the hawk comm is too small

Makes sense, but I had to see it here (again, I think Mike Swiss did the test and cut the brushes) for the bell to ring. After all, it's pretty widely known that going to 36D size brushes in the Mabuchis is only a good thing if you also use a Kirkwood or similar diameter com.

What I would like to try is a pure silver comm with pure silver wire .

Pure silver is softer than copper, so it's probably not such a good thing just because of that (even though it's a better conductor). I'm not sure if there's such a thing as pure silver magnet wire (insulated). Maybe it's used for some esoteric or military-type applications if it does exist. Anyway, I'm sure the cost-is-no-problem racers would be using the stuff if it really were out there. I'm not even sure the old "silver wire" was actually silver (or pure silver) anyway. For all I know, it may have been "silver colored" as there was a lot of "snake oil" sold back then.

My thinking is the neo magnets over power the coils so what if the coils can energize and de-energize a lot quicker
will this help over come the problem of the magnets being stronger than the coils ?

Well, I can say without a doubt that you CAN have too much magnet for a particular arm/setup and application. The drag guys are almost unlimited in their options because the motors will run flat out for a split second...so they can build them completely "balls-to-the-walls" with no regard for heat. The #26 I just did sounds great, but after about 30-45 seconds at half power...maybe a minute, it starts to get PDW (pretty danged warm!). It actually might make a dandy drag motor now that I think of it, but I'd really like to see about making a motor with those neos that could live for a race on a road course.

I'de love to know what and where i can get the machine to make coms so I could try this out

You could ask Ron or Bill Bugenis about the cost, but I think this is only an option AFTER you hit the lottery! You're talking serious money and equipment. If you really have that kind of scratch lying around, can you adopt me?...no...really!

-john

[Coal Train]

There is pure silver well close to pure 99.99% it's called brite silver . And you can get the wire but its not insulateded but a simple bath with a moterized winder can put the insulation on the wire.

The reason why I'm thinking of running this kind of thing is because the motor WILL only run under half a second .
I have been known to spend stupid money on a idea , well designing and the manufactoring of the 12 segment neo's went through various stagers of 10's and 12's at different lengths
and came to a total bill close to $10,000 and now I have enough magnets to last 10 people a life time but hay it's done and they work so in the end I have no idea if it was worth it
but Ive gone the quickest in Australia and Dave Pfaff has gone .4010 and thats pretty close to .3999 , all said and done thats our main goal to get to the .3's
So i suppose the saying at any cost comes into play.

Bill has already expressed that he wont cut the com's so I think it's up to me to get the job done so , seriously how hard can it be , I have a lathe and some pretty smart people around me
so if no one will help then thats the path I have to travel .
I just thought you of all people would have try'ed it at least once .
I must say it's a pretty lonely path outside the box .

Your stuff does look really good though , you give me some one to compaire to .

Thanks for your help John
I'm sure I'm going to hit you up for help again in the futore
Robert K

[havlicek]

I just thought you of all people would have try'ed it at least once .

Well, I've tried a lot of things Robert. A lot of people thought just rewinding was a pretty dumb thing to do in this day of "mostly" factory arms. Just being able to do that has turned into a pretty long trip. Still, making a precision commutator is beyond what I could possibly even think about on a small workbench in my basement. I would wind some arms with silver wire if someone asked me to and had the stuff...but no one ever has!

I must say it's a pretty lonely path outside the box .

...but mostly interesting and fun Keep going your own way Robert. Many times it might only lead to frustration, but every once in a while when you accomplish something cool, that's the big payoff.

-john

[Dan Miller]

Silver commutators and silver wire are not worth it.

Think about the slight benefit of a silver commutator. You are trying to conduct electricity over such a short distance, using motor brushes, with a slotted commutator. Measure that advantage and tell me what you see. Also, the silver would blow away much faster than copper. There are added metals we find mixed in with the copper. Better you develop a new motor brush than a silver commutator.

The small advantage offered by the theory of using silver wire, at the expense and trouble of using it, are not worth the tiny gain available. How about the simple idea of going to the next 1/2 wire size larger and forgetting the idea of silver? It would only benifit you if you were winding armatures for a regulated class of armature with fixed turns and wire size written into the rules. Then you would still have mechanical issues to deal with that you have not thought about yet.

You will gain far more advantage, in a Drag racing effort, by working with magnets, cans, armature blank and motor brush design than you ever will developing the use of silver wire and commutators.

Dan Miller

.

[Coal Train]

Thanks Dan youve put it into a better perspective for me now.

[Coal Train]

So I thought id'e throw a few arms on the meter and see how they read .
1st Arm is a Koford .445 64 wind = 037 mΩ
2nd Arm is a ProSlot .445 double 27 gauge wind = 033 mΩ
3rd Arm is the one from the above photo .445 , 33 wind = 015 mΩ
Really happy with my results
I think everybody should give arm winding a go like Dan said .
I think I'll forget about all that talk about using silver. But then again I still havn't try'ed it yet......hhmmmmmm.

[Gary Lum]

Hi John,

I just read about you trying to get a road course neo motor to live.... Well, we tried a set of neo mags in a billet strap can and endbell. I'm not too sure of the airgap since it's not my motor, but it did have a .459 6/4 Koford arm. It was installed into a Koford open wing car chassis (not too sure about any of the setup or tires... I'm just a drag racer... hahaha). We geared this thing 12/39 and it was a beast even with 15' of choke. Okay, I don't know what the lap times were or what 15' of choke means, but the wing car guys were getting a little nervous watching it run, as it ran lap times that would have put it in the top 2 or 3.... The problem was that it would go into thermal nuclear meltdown after maybe 2 laps on the Gerding King track at Buena Park. If one could find a way to cool this thing enough to make it live for even a 2 minute heat, I think that the cobalts would be history.... There was enough money left over after building that motor for pizza! LOL! I think the guy that built the motor may have gotten a little discouraged after melting 3 arms....

Gary

[havlicek]

Hi Gary,

Yep...that's the thing with the solid neo motors. There's so much magnet there that it's a natural to go for a ripping wind, but then the heat becomes insane. The motor may be at risk, but the magnets themselves are as well because of their lo-heat-tolerance. I've been doing some screwing around with these things and some prototype motors a Blogger sent, and I've started going "the other way" with the sold neos for a road-racing motor. #30 and #31 winds with a big airgap. The motors seem to have loads of torque still, but the RPMs are (of course) down. I'm not sure at that point that you've gained anything, even thjough you should be able to make up for the lower revs by gearing to take advantage of the torque. It's maddening to have THAT much magnet available and not be able to take advantage of it...other than for drags. Seems as though the cobalts still are "it".

-john

[havlicek]

I'm on my fourth arm trying to get this solid neo/road racing motor to run well without getting too hot. I assembled an arm out of .007" lams from arms that had already been ground to .480" diameter...that in itself was a pretty major pain-in-the-you-know-what. These setups use a short stack arm (I forget but it's under .400" length) so I did a 67/30 and it's curing in the oven so I can finish it off later. I then shimmed the magnets so that the hole is around .005" larger than stock. My thinking is that I'm starting out with a slightly larger hole and can then open it up even more if I need to. Even so, the arm still cogs like a sonofagun, but I can turn it a little easier by hand...it was all but impossible stock. I'm thinking I'll either get to a point where it runs like poopie or maybe find a happy medium where the motor has torque and revs that would make this whole adventure worth while. Pictures at 11:00

-john

[havlicek]

hmmm...things are looking a little better.

-john

[Coal Train]

Alright so too much heat on the com when soldering the wire to the tab can destroy the glue under the com and I've heard of people using a small tig welder or similar to solder fix the wire to the tab.
Does anyone have a drawing that shows how to build a back yard job that can be made ?
And John I've sent you a PM in regards to the air gap for your circuit neo motor.
Well I tryed will have to from my pc

[havlicek]

Hi Robert,

We just need to clarify some things here while I try and point you in the right direction.

Alright so too much heat on the com when soldering the wire to the tab can destroy the glue under the com

With the "good" modern coms, the phenolic ( plastic material that makes up the body of the com) is "keyed" to the com plates and is VERY heat resistant, but even it can be damaged by heat. However, making a physically strong and electrically solid connection requires lots of heat. Ironically, using too little heat can cause more damage than too much because it will mean having to stay "on" the joint for too long and passing more heat to the com which can cause damage. It's best to use a lot of heat but for only as short a time as is necessary.

If you really are "soldering" (as opposed to brazing or hard soldering with either jeweler's silver wire or a brazing metal like "Sil-Phos"), best to use a 4% or even a 5% silver solder and NEVER use acid flux. This will require lots of heat, but will result in a stronger connection than you can get from regular 60/40 rosin core "electrical solder". I only "solder" coms on arms using #29 or #30 wire or thinner, and if the arm is for a hot setup...even those will get "brazed" instead of soldered. When I DO solder, I use a 40 watt iron and "get in and get out" quick as I can. It's also really important to clean the magnet wire of all insulation where it passes over the com tab and I also clean all surfaces of the tab itself. There were lots of people who just soldered the wire in the old days (maybe there was specific insulation types for this???) and the insulation was supposed to just "burn off"...DON"T DO THIS. Use good care and clean everything that is to be soldered without weakening either the wire or the tab.

I've heard of people using a small tig welder or similar to solder fix the wire to the tab.

While any heat source can be used for soldering theoretically, a good iron is best. The "welding" process used is really a vague term because it covers everything from induction type welding where the actual copper of the com tab and the magnet wire is "spot-welded" and fused...to "brazing". Typically, the machines used for induction type spot-welding are expensive and fidgety, more suited to an industrial environment where the very short duration of the "contact" and heat (current) can be adjusted and a whole boatload of "identical" arms can be done in series.

***Much better for the home-winder is a form of brazing or hard-soldering where a mostly silver alloy is heated, flows (like solder does) and produces a very strong joint that should be good for something like 1200°F, as opposed to the approximately 400°F melting point of solder. Silver is also a better conductor than copper (or about anything else for that matter) and is itself physically strong. As you can imagine, getting a metal to flow when it fuses at around 1200°F requires a whole lot of heat...and that much heat needs to happen fast and be applied very precisely at JUST the com tab. These joints, when done properly (no small thing in itself) are the best you can get and I would think that the best/most expensive custom arms are probably almost all done this way. It's taken me quite a while to get this "nailed" and I still screw this step up every so often, but I had to figure this out on my own as nobody I could find offered me advice. Probably because even "self-annointed experts" often are only parroting info they saw somewhere else, and have almost always not actually done the work Because it was a chore figuring this stuff out, I'm happy to at least try and get you pointed in the right direction. That (hopefully) will save you some legwork, AND give the "experts" something better to pass on

1)First off, you need to get a brazing metal. I use jeweler's silver wire in the "EZ" or "Xtra EZ" alloy that melts at around 1200°F...safely below the almost-2000°F melting point of copper. I get the thinnest wire I can and then pass it through a jeweler's device (I forget the name, something like a "draw plate"???) that is a small steel plate with smaller and smaller holes. Because the silver is very ductile, you can thin the wire out to say around 30-31gauge or thinner. This is important because it doesn't take much silver for each joint and the thicker the wire, the more/longer the heat will be required...NOT GOOD! You can also use a brazing flux/silver paste combination that jewelery supply places sell in the same formulas/alloys, but I've found it seems to have a very low "solids" content, so the joints may not have enough actual silver...requiring several applications...NOT GOOD AGAIN!

2)Secondly, you'll need a away to apply all that heat precisely. There are nice looking machines available again from jewelry supply websites that can make your life easier. I don't use one, but they seem to fill the ticket nicely...costing somewhere around a few hundred dollars (US). I use a cobbled-together thing I made that cost a total of around $100 or so (maybe less???).

a) For a "power" source, I use a car-starter/battery charger. This is NOT a simple trickle-charger as those can not supply enough current. Look at the specs and see that the unit can supply around 50 amps at a given DC voltage. I think mine cost around $60 and I must have done several thousand joints with it so far and it works just as good now as when I first got it. Ideally, you want something that can deliver that kind of current at as low a DC voltage as possible. High voltage makes it more likely that you will inadvertantly strike an arc, and that will often blow the com tab and/or the wire away...there goes that perfectly wound arm you just worked so hard at. My unit will do that amperage at 6V, which works fine IF you're careful. There are very expensive lab-type or "bench supplies" that can do that kind of amperage at only a couple of volts, if you want to spend maybe $300-$400 or more, at that price...the jewelry-supply machine seems like a no-brainer.

You will need a "heater" or "tip". This is a basic resistance element and is often made of carbon, although solid metals of varying alloys (including tungsten) are used. Of all the ones I've tried, the carbon works best for my setup and is fairly controllable...getting to "yellow hot" or even almost "white hot" within a second or so. You can use carbon brazing rod (these most often have a thin copper jacket) and that works really well. I find that the carbon electrode from inside an old style "zinc/carbon" "C" sized battery works even better. You have to cut off the end of the battery, pull out the electrode from the black gook and clean it off really well. With either carbon brazing rod or the carbon electrode, I sharpen an approximately 2 inch piece to a fine point in a pencil sharpener and then file a nice flat on the end about the same diameter as the width of a com tab (give or take). Then I cut a groove on that flat so that the tip won't slip off the tab so easily...cause an arc...and ruin the arm. The groove works well on straight com tabs and even on the "hook" style such as on the Mura and other older coms.

c) Then you need a way to trigger the circuit, since you can't just be waving around a 55 amp conductor and hope to make and release contact. I use a 50 amp rated boat ignition momentary switch (push button) mounted in a plastic project box that I have on the floor and can trip with my foot., Holding it down closes the circuit/lifting your foot opens it and stops the current flow.

d) Lastly, you need some bits to make a completed circuit with the com, the heat source and the brazing tip. I have a small-clamp I fashioned that fits around the com, and that gets connected by a long enough piece of soft/flexible wire rated to handle the current to the car-starter's negative terminal. I use another clamp I fashioned to hold the carbon brazing tip and that gets connected to one side of a pair of terminals on the footswitch, again by a piece of soft/flexible wire rated to carry the current. The positive terminal of the car starter gets connected to the other footswitch terminal...that's it!

So what you have going on here is a simple circuit where current from the car starter gets passed through the footswitch when closed...through the carbon tip, back out the com to the negative terminal of the starter. This gets the carbon REALLY HOT REALLY QUICK so that it will heat the copper com tab quick and fuse the silver and the wire and the com tab. Using a very small steel brush by hand afterwards to clean away the scale and crud (to help prevent corrosion...AND make things look nice) should show that the silver has fused. If you leave a nice "fillet" of silver on there, it can almost look like a nice solder joint, but one that will be good to a higher temp than it takes to destroy the whole motor, and one that you can be sure will conduct electricity at least as well as just the copper alone.

Getting fairly consistent at this without destroying the com and developing a technique and "feel" for this will take lots of practice. This is not an automated process and feel/timing, the shape of the carbon tip as well as how often you have to reshape the tip, and how to adjust your timing for different wire gauges (*important) can only come with trial, error and patience. If you're uncomfortable with this fairly "gonzo"-sounding method, don't screw around with it. If you're a "go for it" kind a guy and are comfortable with electricity and digging into new projects...have at it!

-john

[havlicek]

hmmm...that was a long post that required some effort, with no affirmation from the questioner that it was even read (much less a "thanks"). Oh well, I hope someone at least bookmarks it for the next time someone asks.

-john

[havlicek]

Back on the road course solid neo motor. I'm on my 5th arm and things are looking brighter. It may not be "there", but somethings I've noticed along the way:

1) High timing seems to be counterproductive with these. It almost seems like the heat increase as the timing goes up is way more than with a ceramic setup. Mild advance (around 15 degrees or so) seems like a good compromise.

2) These motors can get hot from an arm that is either too mild or too hot. If you install a mild (say #31 wind) arm, the motor starts getting magnet bound. The motor may only be drawing a half an amp, but it's getting warm nonetheless.

3) While a drag motor with the solid neos can tolerate (for the short bursts it will be required to run) the tighter airgap and heat, it seems a slightly sloppy hole is the way to go. In order to be able to mess with the airgap, I started using smaller diameter arms so I can then shim the magnets in a little at a time to see how things go as it gets tighter. I have a .513" airgap now and the motor seems to run well with an apporximately .484" diameter arm. That's a difference of .029" or so for around .0145" per side. Arms still spin up and down super fast with those specs, but RPMs seem down so gearing for revs and NOT torque still looks like the way to go.

4) Even with the wider airgap, these magnets exert a lot of force on the arm. It's a lot more important to center the arm in the field since the com or tail end will be pressing hard against either bushing (or bearing) causing wear and heat.

I've finished a 55T/#29 with a Bugenis com on a .484" diameter stack made from .007" lams and around .400" long for the setup and with mild advance. The arm measures .484 ohms (same number as the diameter!?) per pole. I don't think anything milder will be worth it for these magnets; you could probably get better overall performance with the composite/resin bonded neos as in the Falcons or a even a good set of ceramics. I'm going to send the arm out for dynamic balancing when I get the chance, just to be sure the arm has the best chance of performing as well as it can:



-john

[GearBear]

hmmm...that was a long post that required some effort, with no affirmation from the questioner that it was even read (much less a "thanks"). Oh well, I hope someone at least bookmarks it for the next time someone asks.

-john

Awesome write up John! I know I greatly enjoyed reading it. Now I just need to get some time winding some arms so that I can put this great post to use.

[Kim Lander]

John,
Great looking wind, I think you are on the right track, andas for your post getting read....I read them all...who knows I might learn some thing, hope all is well on the island...Kim

[boxerdog]

John, you KNOW we are reading each and every word!!!!!

[NSwanberg]

Thanks John! Just one of your many subscribers.

[Coal Train]

Hi John

Firstly I'm very sorry about not responding to your absolutely fantastic post .
Ive been extremely busy with work and not much time to even think ( auto pilot )
Also with such a great post I feel it needed a well worded smart reply but I got nothing.
It is a very special write up you did a one that a very lot of people are going to book mark.

On a different note you stated your arm meters .484 ohms
now with you saying that I think I'm using my arm meter wrong.
I'm using a Kapriwa the arms meter and I gently press on the arm when I use it with hardly any force because I dont want to dint the com.
So I think I'll just let the arms just sit there on there own from now on .
Yeah big difference between a real nice looking well wrapped arm metering 484ohms to mine with me pressing on it getting 015ohms
but theres two big differences as well to concider you got the smaller wire and I use the bigger wire so my thoughts are still all over the shop

I will be getting one of those jewlers set ups I think a few extra bucks wont be such a bad thing but then again I have been known to give anything a try
at least twice.

Once again mate very nice post and sorry for the late reply.

Robert K