cd-rom tricks

[Ron van Sommeren]

Please don't ask general questions or give pats on shoulders in this thread, just add your tips and tricks and discuss them. Use http://babelfish.altavista.com (http://babelfish.altavista.com/) for automatic online translation.
Never ever connect a brushless motor (whether in- our out-runner) directly to the battery, the motor will act as a short and go up in smoke! Brushless motors MUST be operated with a brushless controller!
Use a DC power supply with a current limiter to protect the ESC during first test runs. Batteries are hardly current limited, to say the least ;) and may fry up the ESC if the newly wound motor has a short in it. If you don't have a power supply, put a heavy a car lamp or a duty resistor between the battery and the ESC. Use few cells that are almost empty. Even empty cells can deliver a lot of current for a very short period of time. However, this period is long enough to ruin your ESC.
LRK and CD-rom motors have different winding diagrams.
Manuals
* Several excellent articles on building lrk and cd-rom motors, pictures, winding diagrams, by Brian Mulder a.k.a. 'Mr DIY' on E-zone:
www.southernsoaringclub.org.za (http://www.southernsoaringclub.org.za/)
-> Articles from Southeasters
-> Electric Motors - part 1 ... part 5
* Motor construction articles by Christo v.d. Merwe (nice motor colours ;) )
www.bavaria-direct.co.za (http://www.bavaria-direct.co.za/)
* Two motorwinding video files, 14 & 10Mbyte respectively:
www.utahflyers.org (http://www.utahflyers.org/)
-> video
-> instruction
* One hour instructional video (on DVD)
www.strongrcmotors.com (http://www.strongrcmotors.com/)
-> instruction docs
* Most, if not all, motor kit suppliers have manuals on their sites, very useful e.g.
www.gobrushless.com (http://www.gobrushless.com/) (link "Brushless 101 (http://www.gobrushless.com/kb/index.php?title=Articles)", must read diy articles)
www.aircraft-world.com (http://www.aircraft-world.com/)
www.strongrcmotors.com/ (http://www.strongrcmotors.com/)
www.e-foamies.com (http://www.e-foamies.com/)
www.dionysusdesign.com/files/CDROM_Instructions.doc (http://www.dionysusdesign.com/files/CDROM_Instructions.doc)
* Very good LRK and dLRK manuals (winding diagrams differ from cd-rom diagrams)
ClassicLRK winding tutorials
pictures:
http://www.rcgroups.com/forums/showthread.php?t=523039
bible_1:
www.powercroco.de (http://www.powercroco.de/) (English and German)
bible_2:
with the original LRK articles (in English) published in the German ElektroModell Magazine in 2000 and 2001)
http://www.aerodesign.de/peter/ -> English
Building/winding manual:
http://www.torcman.de/index_e.htm
-> Manuals (http://www.torcman.de/motoren/manuals/manuals_e.htm)
-> Assembly Procedure TM280, 350, 430 (http://www.torcman.de/motoren/manuals/anl_eco_200e_scr.pdf)
Excellent dLRK winding turorial
http://www.rcgroups.com/forums/showthread.php?t=736580
(http://www.high-torque.com/)
winding tricks, better packing
http://www.rcgroups.com/forums/showthread.php?t=249007
http://www.rcgroups.com/forums/showthread.php?t=447174
http://www.rcgroups.com/forums/showthread.php?t=445750
http://www.rcgroups.com/forums/showthread.php?t=401641
http://www.rcgroups.com/forums/showthread.php?t=381117
http://www.rcgroups.com/forums/showthread.php?t=400958
Personal homepages
www.flyelectric.ukgateway.net/motors.htm (http://www.flyelectric.ukgateway.net/motors.htm) (lots of motorbuilding lathe and mill tricks too)
www.id.ethz.ch/people/allid_list/korosec/privates/ae/motoren/electric/cdrom/ (http://www.id.ethz.ch/people/allid_list/korosec/privates/ae/motoren/electric/cdrom/) -> link "cd-rom conversion story"
http://homepages.enterprise.net/jayjay/cdrom_motors.htm (cd-rom conversion for helicopters)
http://haero.free.fr/maxx_motors/300-manual-2.bmp
http://www.btinternet.com/~michaelhogg/piccolo/cdrom/cdrom_conversion_final.jpg (http://www.btinternet.com/%7Emichaelhogg/piccolo/cdrom/cdrom_conversion_final.jpg) (step-by-step, one large picture)
http://users.compaqnet.be/retlaw (Dutch/Nederlands and English)
More in this two page thread, manuals, homepages, material (magnet!) sources:
http://www.rc-unionen.dk/nytforum/topic.asp?TOPIC_ID=368&whichpage=1
http://www.rc-unionen.dk/nytforum/topic.asp?TOPIC_ID=368&whichpage=2
The metal ring must be mild iron (piping steel). Carbon/aramide/kevlar, plastic, stainless steel, copper, aluminium, glass, ceramics(with the exception of ferrites), wood, resin etc is not suited. These materials behave like air to magnetism, they do not concentrate the flux.
Windingdiagram-table and -calculator:
www.powercroco.de (http://www.powercroco.de/)
-> English
-> winding table and scheme calculator
clear instructive winding diagram pictures
http://www.powercroco.de/
-> English
-> (Tools) winding schemes in pictures
An article by Ludwig Retzbach (the 'R' in lrk) about winding errors:
http://www.modell-aviator.de/content/redaktion/0106_gewickelt/index.html
Use e.g. http://babelfish.altavista.com (http://babelfish.altavista.com/) for translation
Airgap, magnetwidth and -thickness, #magnets, stator- and rotor-diameter calculators:
http://www.gobrushless.com/testing/motor_rotor_calculator.php
http://kreature.rchomepage.com/calculators/airgap.htm
Use good quality wire from a motor/transformer refurbisher/rewinder, they have very good quality double coated wire. Bring your motor (plane, RC equipment) along and you'll probably get it for free. They love to see a motor that can be handled without a crane :)
Don't use cyano-acrylate type glues for gluing the coils, it can be aggressive on some types/makes of wire.
To prevent shorts, round/chamfer/bevel the stator corners a bit with a Dremel (carefully) or a fine file.
When in a very tight winding situation, round the top of the wire to prevent it from scratching the insulation of the previous winds (shorts). Dull the end of the wire, when sewing the last turns in to remove the burr/sharp edge that occured when cutting the wire.
Stator insulation
Making stator isolation plates, video and pictures:
http://www.rcgroups.com/forums/showthread.php?p=10651516#post10651516
Pictures:
http://www.baronerosso.net/forum/showpost.php?p=623909&postcount=5
Don't use teflon tape for insulation, it flows under pressure (the way it's supposed to do):
http://groups.yahoo.com/group/lrk-torquemax/message/153
Use glass/epoxy(cyano) on both stator faces. See the pictures here:
http://www.modellflug-hager.de/lrk.htm
An alternative stator insulation method:
http://groups.yahoo.com/group/lrk-torquemax/message/135
Insulation discussion:
http://www.rcgroups.com/forums/showthread.php?t=373184
Don't pull the wire to tight around the stator corners to prevent shorts.
It can be difficult to keep track of the number of winds during the winding process. Cut wires to equal lengths before doing the winding. If you're one winding of (off?), it will show. This method will not guarantee you get the correct number of windings but at least it will guarantee that all poles have the same number of windings.Take care with thin wires, they can stretch quite a bit.
Winding tricks:
http://www.torquemax.de/TipsMitteWickeln.htm
Try to cram as much copper as possible in the slots. It makes for a lower motor resistance, less losses, lower temperature and a higher efficiency. Use thicker wire or wind 2-3 wires in parallel.
Higher efficiency does not only mean that the motor makes better use of the batteries' power, it also means the motor is able to handle more power before hitting its maximum temperature mark.
An example:
Say the motor has an efficiency of 70% and it can handle 50Watt input. That means it can get rid off 0.3*50=15Watt excess heat. Now, by cramming in thicker wire, efficiency increases to say 75% (I'm a bit optimistic here). The motor's ability to loose those 15Watts has not changed (by radiation, convection and conduction). This means the motor now can handle 60Watt before it hits the 15Watt (0.25*60Watt) losses mark. An efficiency increase of 5% gives an increase in the power to weight ratio of 20%. That's why efficiency plays such an important role, in any motor design: efficiency governs maximum power.
Use a toothpick or a broken prop to push/squeeze the wires a bit.
http://www.rcgroups.com/forums/attachment.php?attachmentid=560137&stc=1
List of possible errors, do's and don'ts, tips:
http://www.powercroco.de/ (English and German)
Checking for shorts during winding:
Connect a battery and buzzer in series. One lead connects to the stator (make sure there's contact with the stator, remove lacquer insulation!) the other lead goes to the beginning of the wire to be wound. Once a short occurs, you will hear it. You can also use an Ohm (resistance) meter for this purpose, some even have a buzzer.
Check for shorts between the phases BEFORE you hook them up in star or delta. Also check for shorts between each phase and the stator.
You can try and use a battery or condensatorbank to 'blow away' a short between a winding and a stator. Connect one lead to the stator and another to the shorted coil for a very short time but be careful! See
http://www.powercroco.de/
Removing magnet wire insulation can be tricky, especially when using thin or litze/multistranded wire. Just heat the end of the wire with a soldering iron on an aspirine tablet. Nasty/acrid fumes.
Neodymium (NdFeB) magnets have a very strong magnetic field. They are also brittle (ceramics). Don’t let them ‘jump’ another, they may chip/break. Randy little buggers them is :)
Be careful with metal filings/parts and magnets. Use sticky tape or sticky paper to remove it.
Gluing and placing magnets
http://www.rcgroups.com/forums/showthread.php?t=452514
http://www.torcman.de/motoren/manuals/anl_eco_200e_scr.pdf (chapter 3)
http://www.solcon.nl/gjkool
Make sure magnets are glued in alternatingly: NSNSNS ...Checking magnet placement: use a spare magnet to feel orientation of the magnets. Attract, repel, attract, repel ... You can use several magnets to create a larger surface magnetpole (cascading/tiling) e.g. NNNSSSNNNSSSNNNSSS is a still a 6 magnetpole motor.
Optional: use an oven to cure and temper the epoxy used for gluing the magnets inside the iron flux ring (bell). But be careful, set the oven to no more than 60°Celsius (140° Fahrenheit) and wait at least an hour for the temperature to stabilise. Ovens have an initial temperature overshoot that will make the Neodymium magnets loose their magnetism irreversably
Use a tool or an extra person to slide the bell&magnets over the armature, you won’t be able to hold it. It will slam home, this is bad for the magnets (any type of magnet) and for the rear ball-bearing on bigger motors.
Spin the finished motor with a Dremel/powerdrill, it will act as a generator. Now measure the voltages between the phases (select AC voltage, not DC), they should be the same. Differences may be due to different number of windings, a short between adjacent winds or shorts between phases. This method will not detect a (+n) winds error on tooth x and a (-n) winds error on tooth y (both teeth same phase) because these errors cancel eachother out. Keep speed the same for all three measurements or you will measure three different voltages anyway due to different voltages induced at different speeds.
Use a DC power supply with a current limiter to protect the ESC during first test runs. Batteries are hardly current limited, to say the least ;) and may fry up the ESC if the newly wound motor has a short in it. If you don't have a power supply, put a heavy a car lamp or a duty resistor between the battery and the ESC. Use few cells that are almost empty. Even empty cells can deliver a lot of current for a very short period of time. However, this period is long enough to ruin your ESC.
Met vriendelijke groeten ;) Ron
• diy outrunner discussion group (http://www.yahoogroups.com/group/lrk-torquemax)
• int. E fly-in & diy outrunner meet (http://home.hetnet.nl/%7Eronvans/), Nijmegen, the Netherlands

[olmod]

On some small cdroms i use small pieces of card between the magnets to stop them jumping together,when im happy with the placement i put a drop of Loctite Black max on each end of every magnet then chuck it in the Dremel hold it inside a toilet roll tube and spin it for a min' or 2,this forces the locktite to even out and mantain ballance as well as fill behind mags'. When cured trim any excess card flush with mag's with scapel then clean up with cotton bud lightly dipped in laquer thinner. It will surprise you how well this works, just check what is spun out inside the tube . :D Black max is good to 100c by the way. Good thread starter too Ron .cheers all.

[olmod]

Try going through your collection of shafts with a micrometer and select the smallest diameter,carefully grind a radius on the end then with a dremel grinder grind across halfway up just past the radius,you will have what is known as a D bit,it acts like a cross between a drill and a reamer,of course you will have to drill a pilot hole first before using the D bit use slow speed and metho' as a coolant lubricator.and so long as you dont keep it spinning in the hole to long you should have a press fit. :D

[olmod]

Use a black marker pen and blacken the inner face of the end bell and the face of each stator end allow to dry,then gently fit and rotate a couple of times,take apart and examine blackened areas for any signs of rubbing,its not unusual to have a group of stator ends rubbing just either file down or dremel sand the high spots but not the whole lot.if end bell rubs ,add small washers onto shaft till you have clearance. :)

[olmod]

Drum sizes for different magnet configurations. :)

[olmod]

You can line the existing bell with old transformer ( i ) lamination iron..a guilloutine helps in cutting the strip width to the depth of bell required, cut longer than needed, hand roll around something wich is about 4 mm smaller to allow for spring back, then start trimming the ends off as they will have a flat on them,when you get close to the inner diameter of your bell,lay on a flat metal surface,take fine flat file one with a smooth edge to go down on the metal surface,squeeze the ring together so you file both ends together on the draw back stroke.by trying you can get a push fit and a perfect butt join.I use a little loc tite black max to glue them in and spin them with a drill in a toilet roll tube to even out and get rid of excess loc tite. I place the first magnet over the but join, when finished placing the magnets,i place a single drop on each end of magnet and use the same spin technique.when fitting stator i use the black marker to show witness to any rubbing and grind accordingly. so i might not be able to use max' thickness magnets but the lamination iron flux ring helps too. ;)

[rysium]

@Rysium/Richard
Might be a good idea to put your double/triple stator torque/power/#wind/force explanation here too. Very instructive :)

Here you go:

adding more iron like that increases the max wattage you can stuff into the motor before the iron is saturated with the magnetic flux created by the coils. Basically, it increases the max power-handling of the motor.

Not just straight so easy. It can increase the max torque achieved by the motor. The torqque will be square to to the stator lenght. Torque easy tranclates to magnetic force between stator and rotor.

In example in twice longer stator you can get twice more MF at the same saturation level but at the same time you can use longer magnets in the twice longer rotor. So the force will be 4 times stronger.
How it translates to power? At the same number of turns you can run twice more current before stator is saturated (this is the part of twice stonger MF from stator). So the power at the given voltage is just twice bigger than in single. But wait, the torque is 4 times stronger, so it must be lower rpm. Yes. Kv of that motor will be 2 times lower.

So how to bring it back to the original Kv (and original rpm)? Use twice less turns. But wait again - you need again twice more amps to get the the saturation level.
So now we have motor that is twice longer with twice longer magnets, with half of original turns (and probably thicker wire) and drawing 4 times more current. It runs the same rpm and delivers 4 times higher torque.

Isn't it slick?

RysiuM

[Ron van Sommeren]

Remove original magnet ring by letting it soak overnight in acetone.

[bz1mcr]

Try going through your collection of shafts with a micrometer and select the smallest diameter,carefully grind a radius on the end then with a dremel grinder grind across halfway up just past the radius,you will have what is known as a D bit,it acts like a cross between a drill and a reamer,of course you will have to drill a pilot hole first before using the D bit.and so long as you dont keep it spinning in the hole to long you should have a press fit. :D

olmod
This sounds like just what I need. Does a D bit look like this?

[Fishnut]

Airgap is not only the gap between the magnet and the stator, the gap between the magnet and flux-ring has the same effect as magnet-stator airgap. Both have to be taken in account. Put iron shims in the space between the magnet and the fluxring, thus reducing the total airgap. Magnetic resistance will be lower, flux increases, less rpm/volt (=Kv) and more torque per ampere (=Kt). Also less chance of local saturation were magnet edges touch the flux ring. More glueing surface too.

Groeten ;) Ron

Along those lines, I now glue magnets to the bell with JB Weld epoxy. Don't know what's in it, but magnets attract the stuff (will even pick up a tube of JB), so it should help in moving the flux along. Put a dab on the bell and place the magnet on it. It will squeeze out the excess. Airgap is zero, though I don't know how efficient the JB Weld is in the flux department.

Kurt

[DEPENDS]

To help prevent windings from rubbing the inside face of the bell, put the wound stator between two hardwood blocks place in vise or heavy C clamp and squeeze for all you're worth. This "flattens" the windings a few thousandths and may be the difference between rubbing and running freely.

JT

[DEPENDS]

If you have problems with windings rubbing on a GB kit, it may be that the plastic retainer ring has been pushed too close to the inside face of the bell. Using a drill press or arbor press, "push" the shaft back into the bell a tiny bit. Because the bearing holder/stator is locked on the shaft by the plastic retainer, moving the shaft back also moves the stator back and provides the clearance needed. Unless there is severe rubbing, just 3-5 thousandths is usually enough to free things up.

JT

[davidsons]

When finished winding, I like to use hot glue to hold the leads tight to prevent them from possibly uncoiling and rubbing.

[olmod]

It will certainly be better than other adhesives,why i say that is because i have read and i did post somewhere a couple of links to the csiro wich have a couple of papers on materials made of compounds i suspect are similar and are useing and testing for manufacture of stators ect, the main thing is not to have any between the magnets as this is detrimental so ive been informed by a manufacturer here in melbourne. imagine moulded stators if you are interested try checking my past posts. :D

[rysium]

When finished winding, I like to use hot glue to hold the leads tight to prevent them from possibly uncoiling and rubbing.

1. For that I use a nylon thread (it's NOT a dental floss, this one comes from the string from old blinders). One yard is good for going 4 times around each pole. I wrap it by doing a "slalom" around the poles, so after first round (9 poles) the string is comming out from the other side, this way two rounds around wrap evry pole from both sides (I hope it's clear).

2. To hold a stock can on the shaft use a prop adapter (or even a collar) that fits tight on the shaft and it's glued to the front of the bell. Any good glue for metal will do (Locite, plasti-zap, JBWeld).

RysiuM

[olmod]

Take one old security camera mount adjustable ball type,add some bits out of a scrap vcr and a cdrm, a few scrap dense wood pieces = Stator winding jig. :)

[olmod]

Teflon tube in forceps and clamped to a desired tension helps.that counter sure does help also. :D

[DEPENDS]

Damn! Never thought of a mechanical counter. Brilliant! A 1/4" long piece of 7/32" alum tubing makes a good spacer between the ball bearings in a GB kit. Keep's the front bearing and plastic retainer in position so that the bearing holder (and stator) doesn't rub the inner face of the bell.

JT

[Ron van Sommeren]

Use a wooden dowel. Don't pull to much on the more thinner wires, they may stretch! Picture from www.torcman.de site.

[olmod]

This is meant as guide to novice bell makers, and not meant as the only way to do it,but has proven to be a reliable way of getting a true spinning bell wi. 1st turn your alloy endplate approx 1mm oversize in all dimensions,while still in lathe chuck,centre drill and drill to 2.95mm diameter as deep as needed.cut off stock with a hss parting tool.2 either using a pedestal drill or you can by reversing your blank in the lathe and using the tailstock and chuck press a 3mm shaft into the blank so that 9mm protrudes out from the small boss side of your blank,it is a very tight fit and you will not need any adhesives.3 now place the 9mm end of the shaft into the lathe chuck and with the parting tool lightly skim the small boss.5 then re chuck on that small boss and make sure that the outside face is firmly against the chuck jaws by tapping lightly,and continue to machine inside face,i relieve about a 1 mm to allow for windings so theres no possibility of them rubbing.6 now machine a 1mm step for the flux ring wich previously has been semi finished within .02mm and loc tite it on while still in the chuck,that way there will be no variation caused by rechucking.7 when cured you can bore to finished size and finish outside and ends.8 finally rechuck with the open end of bell facing towards the jaws and resize the boss and front face ,radius ,and polish.

I hope that the pics will be good enough. sometime back a data base was published that gave makes and models of suitable cdroms for conversions i wonder if an updated version could be included in this thread please for new readers, is it also possible to rename the thread as "cdrom tips n tricks" :)

[dandy]

use a small caculator for counter 1+1 HIT = EACH WRAP FOR COUNT

[rysium]

use a small caculator for counter 1+1 HIT = EACH WRAP FOR COUNT

I would rather use BIG calculator, as it's much easier to hit the right key with your foot.

RysiuM

[DEPENDS]

RysiuM,
That's what make's the mechanical counter so attractive. You can attach a stick, paddle, or string to the trip arm and use your foot, elbow, or nose for that matter. :p

JT

[olmod]

The teflon tube held with the forceps kept splitting :( so have opted for some dense felt folded around the wire and clamped,at the moment i have a lock screw to hold the bearing tube and have to keep undoing it each time i change to the next stator to wind ,got to think up a better way with an index for every 4th stator pole,but there is no doubt in my mind it is a big improvement over any other way as you can see every wind as you lay them down ,and you get quicker :) ,with the aid of a small wooden wedge pushed in between each gap after each layer of wire is wound ,its easy to wind on 15x.5mm turns onto a 20mm stator. :D for all my small wooden tools i use jarra it is hard and has an oilyness to it , do you have jarra in the states?
all pms answered,

[FlyByMike]

... for all my small wooden tools i use jarra it is hard and has an oilyness to it , do you have jarra in the states?
all pms answered,Nope, no Jarra here, though I've heard of it as an exotic wood for use in woodworking :) Oak is very common hereabouts.

Question: do you use the 'handwheel' (red arrow in pic) to rotate the whole shebang while the right hand aims and feeds the wire onto the stator?

Suggestion: For an index could you make some sort of 'yoke' (blue in the pic) that would drop down into the 'spokes' to hold the stator?

-Mike

[DEPENDS]

olmud,
Instead of a wooden wedge (we'd probably use hard maple) I picked up a broken APC prop and trimmed it to an appropriate thickness and used it to flatten the wire between stators. The glass-filled nylon is strong and has a slippery surface. Wedging between stators is a good idea. As you have discovered, it's a game of thousandths.... BTW, I'm left- handed and your explanations make perfect sense to me! :p :D

JT

[Eljimb0]

http://www.rcgroups.com/forums/showpost.php?p=2158813&postcount=322
this is a post on my magnet locating tool. It works fast and does a perfect job every time. I put the magnet in the bell and "sweep" it into place. then touch the manet with a small drop of ca. I have nail holes drilled into the wood now for 14 or 12 stops. The threaded end of the drive shaft tightens the bell to the wood disc (like the prop).
jimbo

[Eljimb0]

I took a thin hollow carbon fiber tube plugged the end with a solid carbon fiber rod. I drilled a tiny hole through the center of the plug with the dremel tool. The magnet wire slides through the thing and it makes locating the wire a snap.I never get shorts or bare spots in the insulation from nicking the hammer head corners. It is a big help if you have banana fingers like I do.

[Eljimb0]

After the motor has been tested I put this stuff everywhere the wires might move. It dries pretty fast and it is clear. It helps keep the soldered leads from getting loose from rough handling. And there is a little brush connected to the cap.
jimbo

[olmod]

I took a thin hollow carbon fiber tube plugged the end with a solid carbon fiber rod.
Yep its good alright! early on i modified a biro and put a small brass tube lined with hard teflon tube lining allowing about a 1 mm sticking out the end but after a few winds the teflon split and the brass scraped off the enamel on the wire,since then ive been hunting for something to replace the tip with like a tungsten carbide bead or a ceramic bead,what i ended up doing at the time to provide tension was to use a piece of dense felt clamped around the wire at the top of the pen wich worked very well. keep the ideas and experiences coming guys .cheers all. :)

[Eljimb0]

"What could be used on the back end of the tube to put tension on the wire for pulling the wire tight?"
The tube is short. The thumb and index finger hold it. My small two fingers and the flesh of my palm provide the tension (drag) on the wire. It works better for me short.
jimbo

[rysium]

Setting 5x5x1 magnets in GBL 22.7 stock bells (maybe for others too).

Don't push magnets all the way down to the bell. Top edge of every magnet should be flush with the edge of the bell and the bottom edge of the magnet about 1mm above the bottom of the bell (this is the level where GBL can has 3 tiny noches on the side. Make sure these noches are between magnets. This setup guarantees enough airgap between magnets and stator and leaves space for wire between front of the bell and the stator.

RysiuM

[olmod]

These layout come from a new member AeroNut45 and i believe there will be shortly one for 23mm stators. :D

[olmod]

I have standardised the way i make connections to my motors,first i use a hole saw of a suitable size to make blanks from fibre glass circuit board then by hand engraving 3 isolated lands and pre drilling holes for the wind wires, enlarging the centre hole for the bearing tube and glueing into place,finally soldering 2mm gold male connectors.then testing the winds for output ac voltage when spun up with dremel or drill, the pic should explanetory. keep the thread alive,contribute. :D

[AeroNut45]

Here the drawings with measurements for those, who got a lathe and a 22.7mm stator from GB, and need to work out what the rotor should measure from the inside to take those magnets I mention in the drawing. I know there are formulars to work that out but not all of us are that smart and have the knowlege me included. I help myself with this graphic drawing program which works with 3 digits behind the comma. I have build one motor going by those measurements I worked out. It worked out just right.
There is one part which would be hard to work by formulars, that is the smaller distance between the magnets. I can measure that in that program. If I am out there with my figures it would be only because I can't determine what the corner radius would be on those magnets. That will ultimately dictate the thickness of the spacer to use.
Here a question for ruisum: the 2nd magnets in this pdf I have drawn up are only 2.5mm wide, would that give enough coverage? Those are magnets I have on hand.
If these drawings find general approval, I am willing to help if someone needs a drawing with different stator sizes.
AeroNut45

[AeroNut45]

Here is another question: would there be an atvantage to have the rotor with 12 flats instead of being round. I have got a dear friend who offered to press me a rotor like that. It would mean quite a bit of tooling. If it is only for attaching the magnets better, then it is not worth the effort.Will it change the magnetic field for the better?
Who of the gurus can answer that?
AeroNut45

[arx_n_sparx]

Aeronut: It will help marginally the magnetic field marginally - how much I don't know. The best way would be to put up the $$$ and get some of the "arc segments" from Mr. George: http://www.engconcepts.net/Magnets/Pages/LRK_Torquemax_Magnets.html

As Ron asked at the start of this thread that we only post tips and tricks here, you should be asking questions like this on a different thread.

Brad


AeroNut45's pdf posted here:

[olmod]

By gee he does nice work though EH? :D

[olmod]

when finished a known winding, finish by adding a small amount with a toothpick your favourite epoxy to windings, you dont need much and warm up stator and watch the epoxy just wet out and spread,it stops any loose wire from moving and rubbing through enamel coating on the wires and moisture proofs. ;)

[mgdon]

I bought some JB weld and put a dab of each part on a piece of paper, mixed it and let it set up.
After it cured I tested a neodymium magnet with it and it is not attracted to it.
For whatever it's worth on the package it also says "does not conduct electricitry".
The package I bought is black and red with a white background and the two tubes are 1 oz.each.
Is this the same as yoiu tried?

[AeroNut45]

Have been around to olmod today. I have been intrigued by his winding device. Have taken another picture of it. I think it has changed since he has shown it last. I didn't realise at the time that it is failsafe what the counting is concerned. For each turn, one has to turn the wheel on the left, in order to see the top of the stator and then the bottom. You can only turn the wheel in on direction. You turn it the wrong way and the lever on the counter will stop it from going back. I think that is very nifty. So one can concentrate on getting the wire on neet.
It also acts as a little vice for doing the soldering as you can see in the pic.
Full marks from me.
AeroNut45

[olmod]

try drilling the serial computer plugs and socket mounting plates apart some ive used (once you get rid of the metal,)the plastic body can be split they are not welded and come apart easy u can use the pins and sockets individually or as is,depending on brand each pair of pin and socket can pass 2 to 5 amps ,even glued together without the metal are very lightweight and if useing for brushless motor connection you can wire 3 pins per phase. i am going to make a plain fibre glass circuit board similar to the others in previous pics, but make it pear shaped and glue the pin half to it and solder the coil wires directly on to three pins per phase. these d series connectors would be also handy in other applications such as shorting plugs ,switch.ect.best part is there cheap as ,gold plated,and any old computer has them. just need some heat shrink on esc leads,and you dont have to have a tug of war to get them apart. :D

[power]

I don't know if anyone has posted anything about holding onto the stator while winding but this is my winding stand, you can get the same results from taking a 5/16-18 cap screw (a long one maybe 5 in) screw a nut on all the way and snug it up. Now go to the grinder/sander and spin the nut down enough to shoulder on the non insulated part of the stator, Take another nut and do the same thing, put the stator on the screw and snug up the nut, clamp the screw in a vise and you have a third hand. This really helps getting the windings tight :)

POWER

[rysium]

To mount GBL motor on GWS stick (the one used for GWS gearboxes) you can get expenisive plywood monts or 5 minutes DIY.
Get GWS gearbox. I bought mine at LHS for $1.25 plus tax. Cut off the can mount and use the stick mount (see the pictures). Now glue it to BB tube (any CA is fine) and wrap it with thread (any thread is fine), then soak the thread with thin CA. It is the strongest mount you can get. And it's light too. My skale shows 1g so with the thread and CA it will be no more than 2g. Can you beat that?

Note: I have updated two pictures. Thy shouw the entire assembly. Motos uses GBL CF BB tube.

RysiuM

[jskrebs]

1 small ty wrap and 4 pieces of .050 CF rod

[MorrisM]

If you are getting along in years like me, and your eyes aren't what they used to be, these magnifying goggles are a big help. I can't do a neat wind without them. Local Harbor Freight had these on sale less than $3.00.

Morris

[Kinda Wild Bill]

I originally posted this in another thread and someone suggested that it should also be posted here.

When mounting 5x4x2 magnets on the new GB custom flux ring I have found that they can be equally spaced around ring by cutting short pieces of 3/32 inch OD brass tubing and placing a piece between each magnet. It's a good tight fit and holds well. I don't leave the tube pieces in there permanently, just until the magnets are glued in.

Bill

[RobinBennett]

Stainless steel isn't magnetic; so any pins, needles or tweezers made from it are great for pushing magnets around - much stronger than wooden toothpicks.

[TeamSME]

One tip I have is to place the magnets on the bell then glue then when you satisfied with the gap.

My first motor
17turns newb wire
Star/WYE
N45's
Go Brushless Kit

hey its my 700th post 300 to go!
http://www.rcteens.org/forums/uploads/post-3-1092713945.jpg

Sean

[Amos]

A simple test rig

The prop is mounted inverted, "pushing" down on the scales.

[vox]

If you simply wind by hand and have trouble gripping the wire, I've had good results with using a latex rubber glove for the winding hand. It grips the wire extremely well and makes the job a lot easier.

A wittled down chop stick can help squish windings between stator winds to make extra room for more windings.

[bz1mcr]

The first photo shows the spacer in a can. It's fast, easy and precise.

EDIT 10/10/04 Production spacers now available! from Strong RC Motors (http://www.strongrcmotors.com)

[Amos]

If you still have a match you can use it for 25 mm plates alignment :)

The stators slots are aligned with groove in the bearing tube. A simple
pin locks them.
The matches are used to align the stator plates when gluing the hub to
the bearing tube.

[olmod]

Interesting winding data for 20mm stators.


http://www.eflypower.com/modules/newbb/viewtopic.php?topic_id=9&forum=4

[rysium]

Airgap, magnetwidth and -thickness, #magnets, stator- and rotor-diameter calculation:

Or this one, if you want it off-line using Excel. This one has all three GBL stators predefined, you can change all blue fields (number of magnets, thinckness, width, center airgap and bell thickness), and spreadsheet will calculate the rest.

RysiuM

[Jay C]

Ok, I've used Richards Spreadsheet and added the spece between magnets and space for magnets calculations. I also fixed a bug and now it draws the number of magnets correctly (would only do a max of 12 before). Not sure why you would need or want space for magnets but there it is anyways :)

Calculator (http://gobrushless.com/testing/motor_rotor_calculator.php)

I'll work on letting you specify multiple mags per pole.

Jay

[flypaper 2]

One of the limits on how many amps you can draw is limited by how hot the coils get, so I used the three holes in the bell as a cooling fan. Before i glued the magnets in I drilled the holes out to 1/8 in. Put a small punch or drill shank in the hole and bend it in the direction of prop rotation to act like an airscoop. Grind the inside where it sticks out on the inside so it won't touch the coils or flatten the inside with a punch. Havn't tried with a temp gauge, to tell the difference but will do and let you know.

[Ron van Sommeren]

You can try and use a battery or condensatorbank to 'blow away' a short between a winding and a statort. Connect one lead to the stator and another to the shorted coil for a very short time but be careful! See
http://www.powerditto.de/
-> tools
-> praktische Bautips
-> picture 5
Use http://babelfish.altavista.com for automatic online translation.

[Ron van Sommeren]

Removing insulation lacquer/resin can be tricky, especially when using thin or litze/multistrand wire. Just heat the end of the wire with a soldering iron on an aspirine tablet (acetylsalicylic acid). Nasty fumes :( you may have to take an aspirine yourself :)

[rysium]

Just heat the end of the wire with a soldering iron on an aspirine tablet

I tried it with the tablets I had here. It didn't work because it looks like 90% of the tablet's mass is some kind of sweet filler (sugar :confused: ). Anyway, heated made a sweet fumes like burning sugar mixed with terrible odor (acetylsalicylic acid :confused: ). I had a big bubling goo on whe wire that didn't even touch the insulation.
I guess, I need to buy a Bayer :rolleyes:

RysiuM

[bz1mcr]

Here is a bench test mount. It is easy to make, and simple and safe to use.
It is very helpful when making motor comparisons, because motors can be switched in a few seconds.

Fabrication:
1. Start with 1/2 plywood or similiar material.
2. Drill a hole sized to your motors bearing tube.
3. Make a saw cut thru the hole.

USE:
1. Clamp lightly in a vise. (Squeezing the saw cut.)
2. Insert motor.
3. Snug vise

Have fun!


Visit Strong RC Motors (http://www.strongrcmotors.com) for custom setscrew motor mounts.

[olmod]

When i was looking around for a suitable low loss cable to hook up to my dyno meter box to monitor amps and volts,it was suggested to me to have a look at Jumbo speaker cable,plenty of fine strands robust around the work bench,and is low loss,oh and the cool look factor. :D Thanks Brian. ;) BTW size of wire was selected to suit 20 amps.i use a p10 controller.

[Amos]

When i was looking around for a suitable low loss cable to hook up to my dyno meter box to monitor amps and volts,it was suggested to me to have a look at Jumbo speaker cable,plenty of fine strands robust around the work bench,and is low loss,oh and the cool look factor. :D Thanks Brian. ;)

Olmod,
I have been using speaker cables on my brushed motors. Only problem -
the insulation cannot sustain heat. Be sure to use larger cross section area
than you normally would.
Amos

[arx_n_sparx]

Olmod,
I have been using speaker cables on my brushed motors. Only problem -
the insulation cannot sustain heat. Be sure to use larger cross section area
than you normally would.
Amos
I would NOT kibbitz in this thread, but Olmod is right. Speaker wire is generally rated at 60° C. Not the best stuff to use......

Brad

[empeabee]

The fit of the endbell and shaft is VERY tight ( by design - so it doesn't start slipping later in the motors life ).

I stacked up a pile of 3mm washers on the shaft and then used a 3mm nut to pull the bellend onto the shaft - adding washers as required.

Note
I got a bit carried away and pulled the bell about 1mm over the 'lip' of the shaft and had to shorten my bearing tube. :(

RysiuM sugested some Lithium greese on the thread, and also tapping a long nut with clearance hole to save having a stack of bowed washers left over looking for a home.

Mike

[Amos]

It is uneasy to glue a second row touching the adjacent magnets of the same
polarity, i.e the bottom edge of the magnets in the second row touching the top edge of the first row.

A simple stick with a magnet glued at its end makes this much easier.

With the "magnetic stick" pick up a magnet and place it in the can, with its
edge touching a same polarity magnet in the first row. The placed magnet
will not be repelled and is easy to adjust with a toothpick.
Apply CA carefully - not to glue the "picked" magnet to the stick magnet.

Place all magnets of the same polarity one after another. Only then unglue the magnet from the stick, and glue it again after you turned it over. Proceed to glue the remaining magnets.

In the second picture the magnet has not yet been glued - but keeps
stationary.

[olmod]

Arround my workshop there is on occasion a bit of magnetic dust due to grinding ect' when building or even sometimes checking i use a piece of 3/32"brass tube about 4" long around one end i put a small wad of that sticky black automotive putty and roll it around inside the magnets pushing into the gaps between as well to pick up any unwelcome guests,its quite surprising how much it can absorb. :D those magnets are so strong they just suck it out of the air. when im happy that a motor is clean i bag them or box them. :)

[Art Newland]

BTW, in addressing the whole "removing the enamel" thing, for soldering the wires when you are done winding, guys are using aspirin to eat off the insulation, because aspirin has acid in it (I suppose). Well... I got to thinking, maybe other acids would work also. I took some soldering flux used for sweating copper plumbing, put a little on a metal surface, sat the wire in the flux, and heated it with a soldering iron. Worked a whole lot better than aspirin, and smelled a lot better too. I was able to solder directly to the wire after. I'd still say use a lot of ventalation.

[Art Newland]

BTW, in addressing the whole "removing the enamel" thing, for soldering the wires when you are done winding, guys are using aspirin to eat off the insulation, because aspirin has acid in it (I suppose). Well... I got to thinking, maybe other acids would work also. I took some soldering flux used for sweating copper plumbing, put a little on a metal surface, sat the wire in the flux, and heated it with a soldering iron. Worked a whole lot better than aspirin, and smelled a lot better too. I was able to solder directly to the wire after. I'd still say use a lot of ventalation.

I also found out if you tin your soldering iron well before you do this, it transfers the heat better, and tins the wire at the same time.

[vox]

Here's a good one for holding those bearings in the GB1.1 kit bearing tubes.

I cannot remember the exact size of the tubing, but I found some left over aluminium tubing (bought from a local hobby store) that fits tight (but not too tight) in the GB1.1 kit bearing tubes. I cut the Al-tube shorter than the bearing tube, leaving about 3-4mm either end (for bearings) and now the bearings just drop in and sit there.

With the long GWS shafts, you wouldn't even need to glue the bearings in - they'll be held in by the bell and the e-clip.

[iflyrc71]

Here is my cd-rom trick cool tip that is...
http://www.rcgroups.com/forums/showthread.php?p=2599063#post2599063

[Ron van Sommeren]

Removing insulation using soldering flux:
http://www.rcgroups.com/forums/showpost.php?p=2597743&postcount=82

[rysium]

First I want to point out, that it's better to use the right size magnets for the job, rather than splitting them to fit. If you can get 5x4x2 or 5x3x2 by the all means use them, instead of breaking 10x4x2 or 10x3x2 in half.

However if you have a whole stack of 10mm magnets (like do), but you need 5mm there is a simple way do do it. "Simple" if you have right tools :D

1. I use old caliper as a magnets support. Caliper is made out os steel, so magnets "stick" to it without moving. Caliper has a small straight grove in the center, so magnets can break easy.
I place the magnets lined up along the grove, and I mark the center line.

2. A small drill (like 1/16) is placed on the magnets on the center line.

3. All together is pressed on my arbor press. Before I bought the press, I used a vise. But press is much easier to work with. Not much force is needed to break 2mm magnets in half

Do not forget to protect the exposed magnet's surface from the elements. Use paint, glue or whatever is good to seal it of and protecting magnets from "rusting".

RysiuM

[iflyrc71]

Here is my picture for my tip on cutting holes on top for the homemade motors..

[lensrc]

A quick tip for the insulation problem: Buy solderable wire. I used Beldon, but now get it from an electric motor manufacturers supply company. I gotta buy 10 lbs to get it there, but it is a lot cheaper per pound, and I dont gotta strip the insulation, just use a 750 degree iron.

[rysium]

..cutting holes on top for the homemade motors..

I have notice funny thing. My motor with 12 magnets 5x3x2 (about 3mm distance between magnets) works like a centrifugal fan. Magnets work as a fan blades forcing the air between magnets back and out. I noticed that when I run the motor without the prop, and it still made a lot of wind behind it. So cooling holes in the front plate are quite efficient for keeping the magnet's temperature down.

Just another reason for using 2mm thick and 3mm wide magnets :D

RysiuM

[Carl]

BTW, in addressing the whole "removing the enamel" thing, for soldering the wires when you are done winding, guys are using aspirin to eat off the insulation, because aspirin has acid in it (I suppose). Well... I got to thinking, maybe other acids would work also. I took some soldering flux used for sweating copper plumbing, put a little on a metal surface, sat the wire in the flux, and heated it with a soldering iron. Worked a whole lot better than aspirin, and smelled a lot better too. I was able to solder directly to the wire after. I'd still say use a lot of ventalation.

If you use any kind of acid to clean the insulation, be sure to clean all of the acid off your work or you will end up with the acid eating your pretty new motor weeks later.

Carl

[olmod]

This may help those wanting to drill thin metal drums,air holes ect' http://www.rcgroups.com/forums/showpost.php?p=2633384&postcount=12

[lensrc]

Commonly known as "Bullet Bits" :)

[Eljimb0]

Squeeze the pair into a small "O" ring. Ca glue the ends together . Gently remove the "O" ring to use it on the next pair. Voila' one magnet from two.

[Eljimb0]

Machine a "plug" to fit perfectly in hole of drill press plate (pic 2). Notch disc with evenly spaced intervals. 5,6,13?. Drill a corosponding hole in the base of your harbor freight $39. drill press. Tighten plug, disc and bell together with drive shaft diameter bolt. Hold disc still with C clamp.
Fast easy dependable.
jimbo

[olmod]

Some sizes in car exhaust pipes are usefull,go raid the cut off bin at your local exhaust centre,they only throw them out anyway :D

[bz1mcr]

I needed soldering jigs to solder setscrew hub on cans and to make extended cans for double stator motors. When making the second jig I realized it could be modified to do both jobs. It's easy to use and results in true running cans and the lightest double cans (8g) available. It's easy to make if you have a lathe and can be purchased from Strong RC Motors (http://www.strongrcmotors.com) if you don't. Hubs and can extensions cut from standard cans are also available.

[olmod]

This is a scource for motor builders for flux ring material,a speaker manufacturer here in melbourne imports very special magnetic iron wich machines very nicely,to make pole pieces used in his speakers,so save any old speakers the centre pole piece in particular. :D

[Hogster]

Having briefly skim-read this thread I see people have found quite a few methods for removing the enamel from copper wire to allow them to solder to it. Here's my method! Put some solder on the end of a hot soldering iron so it forms a big molten blob. Hold the end of the enamelled copper wire in this blob and wait for the enamel to burn off - you can tell when this happens because smoke is given off and the solder then sticks to the copper.

Job done :cool:

[olmod]

I just pulled apart an old magnavox 10" speaker ,the centre pole piece measures 38x23mm with a 10mm hole a nice lump of the right kind of metal ;) thinking on about machining flux rings, what do you think about on one end of the flux ring if one turns down it to half thickness a 1.2mm length male shoulder and on the other end a female so if you want a double or a tripple ,just loctite as many as you want together ? :rolleyes: as this is not a chat thread ,any pms' answered.

[olmod]

ill get it right :D

[cfischer505]

Well here is one tip, not sure if its been posted yet, I didnt see it.... when you have to fit a GB custom Endbell into a GB custom Fluxring which almost needs a press to do this, put the endbell into the freezer for an hour and the flux ring in the oven at 200 degrees for 15 min. Use an oven mit and assemble the parts which should go together pretty easy... also when you heat the flux ring lay it on its end not side...

[SoMoney]

I was wondering, wouldn't angled holes offer better ventilation to the interior than this? When those motors get spinning fast every little cooling trick helps ;)

Machine a "plug" to fit perfectly in hole of drill press plate (pic 2). Notch disc with evenly spaced intervals. 5,6,13?. Drill a corosponding hole in the base of your harbor freight $39. drill press. Tighten plug, disc and bell together with drive shaft diameter bolt. Hold disc still with C clamp.
Fast easy dependable.
jimbo

[cfischer505]

I found that some cdrom drives have a small belt and motor that operates the tray. Some of these small belts are just the right thickness and diameter to serve as a spacer at the bottom of a 22mm can to keep the magnets from sliping to the bottom of the can.

[SMaric]

48mm Inside diam Can with 10 magnets
Draw a circle, with 10 spokes (36 degrees apart) - I used a CAD package (but lots of other ways)

Cut it out, put it in the Can and mark the inside walls with a marker pen

Position the first magnet
Let the 2nd magnet attach to the first - now flip it over and slide it around to the next marker
Repeat around the can

BEFORE you glue them in place - use a small Bar magnet to check that you have got the correct NSNS....

Now glue them in place

[rysium]

BEFORE you glue them in place - use a small Bar magnet to check that you have got the correct NSNS....


It has been only once when I messed up the polarity of the magnets. After I implemented simple method I have always magnets the way they ahould be.

1. Lay all the magnets side by side on the flat steel bar (I use old caliper). Make sure every mognet repeals it's both neighbors - they just don't want to stick to each other. This is 100% proof that all magnets have the same pole up.

2. Use permanent marker (or any marker that will stay for a while) and "paint" all magnets from the top.

When I install magnets in NSNSNS pattern I always set every other magnets with painted side up. It is easy, as they don't want to stick to each other. Then I tack glue them in place so they don't move. Then I install remaining magnets this time painted side down. I use a toothpick to position them in place.

Easy, and you don't need a lathe to do that. :D

RysiuM

[Uttam1]

For magnet placement, just place the magnets so that the "sides" of the magnets ( The thickness ) attract each other. If they repel each other, you've got it wrong, flip the magnet and it should get fixed.

[SMaric]

My Floppy disc motor had a 4mm shaft

Rather than trying to make a shaft coupler
(only found a Meccano 3mm - 4mm coupler & that was 20mm long with a 10mm OD)

I have found that you an get some plastic tube/pipe connectors (for Homebrew/chemistry piping)
In the UK they're sold as 'PolyPipe' connectors

You need to run a 3mm drill through them - but that's easily done - then they are a good snug fit (tapered) into the 4mm hole in the Can

[latrans]

My idea for joining two cans together to make a double. Pull out both stock magnetic rings carefully, you should be able to get one out intact or mostly intact. Now place the magnetic rind half way inside one can and then slip the other can over the protruding magnet ring. Solder and then cut the top off of one of the cans. Viola.

Latrans

[olmod]

You have finished the bell assembly try setting it up in a magnetic prop ballancer ,you may get a surprise and have to do a bit of adjusting ,even some store bought motors are a long way out of ballance. :rolleyes:

[mgdon]

Olmod,
I've noticed the same thing.
Any ideas how it would be best to balance them?

[Bilbobaker]

Olmod,
I've noticed the same thing.
Any ideas how it would be best to balance them?

To balance mine I just drilled holes in the flux ring. I wonder if just adding some lead between the magnets would be better though.
Would only work on the 4mm wide magnets right?
Seems like drilling holes will make weird things happen in the magnetic field on the flux ring.
I used to play with magnets and paper sheets and iron filings as a kid and you can do some really strange magnetic field distortions buy drilling holes and glueing pieces of magnets together etc.
Bill

[AIR MOVER]

:p You an use 3mm bolts and nuts as a option for bad bells that wont hold the stock shafts... I grind off the hex head on the bolt.. smooth and round the end off .. then grind down a 3mm nut to half its thickness then center the bolt in the bell with some thick ca and zap it dry fast.. then run down the front nut tight .. easy fix.. most hobby stores carry the metric bolts in the parts dept for rc cars... I use the 3X50mm bolts there is plenty of unthreaded shaft for the bearings and enough threaded area for gws slowfly props and spinners.....here is a pic .

[Ron van Sommeren]

Reducing stator diameter


... I have on a number of occassions done this by either chucking in a pedistal drill or lathe and using a fine tooth file and or emery paper backed with a file with success, just dont try it with a cutter, ;)

... I mounted the spindle and finished stator in the lathe, and strapped my Dremel to the tool post. With the lathe turning slowly, in the oppisite direction of the dremel, I ground it down with very good precision, resulting in the tightest air gap I have ever achieved.

Len
I usuallly put it in my dremel tool, spin it up, and lightly press it against a running belt sander ...