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Prof100
10-12-2007, 07:55 PM
Does anybody know how to read the Towerpro model number nomenclature? That is, what do the first number numbers mean (other than a part number) such as 2409? What does the suffix mean such as 18T? Does the 18T stand for the number of turns of wire windings?

Thanks in advance for your comments and insight.

Gnascher
10-12-2007, 08:58 PM
I would like to know this too. Subscribed.

Dr Kiwi
10-12-2007, 11:28 PM
I thought it was "stator diameter, stator thickness - # of turns".

proffcharlie
10-17-2007, 10:59 AM
Just my findings. 24 would be the outer diameter of the stator, 09 is the length of the stator and 18T is the number of turns of wire on the poles. There are other codes such as a triangle or the letter D indicating the windings are terminated in the Delta configuration. The letter Y or a star on the motor case or an astric (*) on the spec sheet or the word wye meaning a wye termination. The letters AIL indicate an aluminum flange style mount, an L means a long shaft, An S means a short shaft, etc. If you Google TowerPro you will find their web site and they list the spec sheets for all of their motors. Their product display is broken down into each series of motors (2400, 3500, 2800,etc) along with a picture and brief suggestion of application of each variant of the series. Web site is www.towerpro.cn

Charlie

Prof100
10-17-2007, 01:27 PM
Just my findings. 24 would be the outer diameter of the stator, 09 is the length of the stator and 18T is the number of turns of wire on the poles. There are other codes such as a triangle or the letter D indicating the windings are terminated in the Delta configuration. The letter Y or a star on the motor case or an astric (*) on the spec sheet or the word wye meaning a wye termination. The letters AIL indicate an aluminum flange style mount, an L means a long shaft, An S means a short shaft, etc. If you Google TowerPro you will find their web site and they list the spec sheets for all of their motors. Their product display is broken down into each series of motors (2400, 3500, 2800,etc) along with a picture and brief suggestion of application of each variant of the series. Web site is www.towerpro.cn (http://www.towerpro.cn)

Charlie

Charlie,

Thanks. I assumed there was a rational scheme to the numbering.

I have googled Towerpro before and all I get are on-line hobby shops who sell the motors. The link you provided did not work for me.

simibill
10-17-2007, 02:15 PM
Just my findings. 24 would be the outer diameter of the stator, 09 is the length of the stator and 18T is the number of turns of wire on the poles.
Charlie

That doesn't make sense. 24mm = .94", and 9 mm = .35" rather small me thinks. The TP spec sheet shows a 2409 series motor as having dimensions of 31x62

Glacier Girl
10-17-2007, 03:19 PM
Well they did exist.
TOWER PRO (http://rds.yahoo.com/_ylt=A0geu_J8ChZHpX8Adu9XNyoA;_ylu=X3oDMTE5bXQxZnF 1BHNlYwNzcgRwb3MDMQRjb2xvA2FjMgR2dGlkA0gwMTlfMTE4B GwDV1Mx/SIG=11b1a8ag9/EXP=1192713212/**http%3a//www.towerpro.cn/)
Tel:+86-755-28155180 Fax:+86-755-28156903. Overseas inquiries: towerpro@hotmail.com ... TOWER PRO Electron Co,.Ltd is a comprehensive company, which ...
www.towerpro.cn - 10k - Cached (http://rds.yahoo.com/_ylt=A0geu_J8ChZHpX8Ad.9XNyoA/SIG=150hlj3jd/EXP=1192713212/**http%3a//216.109.125.130/search/cache%3fei=UTF-8%26p=towerpro%26fr=b1ie7%26u=www.towerpro.cn/%26w=towerpro%26d=MSdr6udmPmw0%26icp=1%26.intl=us)

Appears the site is down. Maybe try the e-mail address. I just did, and the e-mail seems to work, at least I haven't gotten a reject back that the e-mail address isn't any good.

Glacier Girl
10-17-2007, 03:26 PM
Look I found the Polish TowerPro site, least I think it's Polish, but it is a T/P site, I tried downloading the spec sheet but my system at work won't open it. Dang security systems.

But anyhow it is there.

Prof100
10-17-2007, 04:46 PM
Thanks to all for trying to decipher the Towerpro naming/numbering scheme. It has to be rational.

Glacier Girl,
Do you want me to send you the Towerpro spec sheet, I have a copy I can send you. Just PM me your email address.

Glacier Girl
10-17-2007, 08:48 PM
Thanks to all for trying to decipher the Towerpro naming/numbering scheme. It has to be rational.

Glacier Girl,
Do you want me to send you the Towerpro spec sheet, I have a copy I can send you. Just PM me your email address.


Bill, e-mail is shelby1@winbeam.com

Thanks.;-)

Dr Kiwi
10-18-2007, 01:06 AM
That doesn't make sense. 24mm = .94", and 9 mm = .35" rather small me thinks. The TP spec sheet shows a 2409 series motor as having dimensions of 31x62

But those are stator dimensions, not the bell OD and total motor length.

Dr Kiwi
12-20-2007, 04:10 PM
<table border="0" cellpadding="0" cellspacing="0" width="100%"><tbody><tr><td colspan="2" height="82"><table align="center" border="1" bordercolor="#000066" cellspacing="0" height="71" width="603"><tbody><tr><td align="center" valign="middle" width="65">Model</td> <td align="center" width="96">Demension
</td> <td align="center" width="64">Weight
</td> <td width="62">Operating current
</td> <td width="71">Voltage
</td> <td class="STYLE10" width="76">KV
</td> <td width="56">Bttery
</td> <td width="79">Propeller
</td> </tr> <tr> <td class="STYLE28" height="28">2409GS-12T-△</td> <td rowspan="5">∮31*62mm</td> <td rowspan="5">65g</td> <td>23A</td> <td rowspan="12">10V </td> <td>1600RPM/V</td> <td> 3LIPO</td> <td>8*4;8*5</td> </tr> <tr> <td height="28">2409GS-18T-△</td> <td>15.5A</td> <td>1000RPM/V</td> <td>4LIPO</td> <td>8*4;8*5</td> </tr> <tr> <td height="28">2409AlS-12T-△</td> <td>23A</td> <td>1600RPM/V</td> <td> 3LIPO</td> <td>8*4;8*5</td> </tr> <tr> <td height="28">2409AlL-12T-△</td> <td>23A</td> <td>1600RPM/V</td> <td> 3LIPO</td> <td>8*4;8*5</td> </tr> <tr> <td height="28">2409AlL-18T-△</td> <td>15.5A</td> <td>1000RPM/V</td> <td>4LIPO</td> <td>8*4;8*5</td> </tr> <tr> <td height="28">A2409-12T-△</td> <td rowspan="7">∮30.6*47mm</td> <td rowspan="4">70g</td> <td>23</td> <td>1600RPM/V</td> <td>2-3LIPO</td> <td>8*3.8;8*6</td> </tr> <tr> <td height="28">A2409-18T-△</td> <td>15.5</td> <td>1000RPM/V</td> <td>2-3LIPO</td> <td>8*3.8;8*6</td> </tr> <tr> <td height="28">A2409R-12T-△</td> <td>23</td> <td>1600RPM/V</td> <td>2-3LIPO</td> <td>8*3.8;8*6</td> </tr> <tr> <td height="28">A2409R-18T-△</td> <td>15.5</td> <td>1000RPM/V</td> <td>2-3LIPO</td> <td>8*3.8;8*6</td> </tr> <tr> <td height="28">B2409L-12T-△</td> <td rowspan="3">63g</td> <td>23</td> <td>1600RPM/V</td> <td>2-3LIPO</td> <td>8*3.8;8*6</td> </tr> <tr> <td height="28">B2409L-18T-△</td> <td>15.5</td> <td>1000RPM/V</td> <td>2-3LIPO</td> <td>8*3.8;8*6</td> </tr> <tr> <td height="28">B2409S-12T-△</td> <td>23</td> <td>1600RPM/V</td> <td>2-3LIPO</td> <td>8*3.8;8*6</td> </tr> </tbody></table></td> </tr> <tr> <td> </td> <td> </td> </tr> <tr> <td height="19"> </td> <td class="STYLE10"> </td> </tr> <tr> <td height="65"> </td> <td>L----long shaft S----short shaft T----turn/loop G----gold tail Al----aluminum tail R----reverse output shaft A----iron head △----trigonal twirling wire B----aluminum head</td></tr></tbody></table>

oct2633
01-19-2008, 09:05 PM
Bill, e-mail is shelby1@winbeam.com

Thanks.;-)


I too would like a copy of those specs. Thx.
oct2633@aol.com

oct2633
01-19-2008, 09:20 PM
I thought it was "stator diameter, stator thickness - # of turns".

Dr. Kiwi, you are correct. Thank you.

shotgunsmitty
02-02-2008, 06:02 PM
That's some good info right there. All that was Greek to me before I read this.

Thanks!

Dr Kiwi
02-22-2008, 01:32 AM
That's some good info right there. All that was Greek to me before I read this.

Thanks!

Still is since Delta △ seems to figure a lot!

Prof100
02-22-2008, 01:57 AM
You also may want to bookmark the Towerpro website. See below:

http://towerprocn.sh15.host.35.com/towerprocn/index.html

dbcisco
08-22-2008, 01:39 AM
Two questions.

Can I use Wye and Delta wound motors with standard BL ESC's?

Anyone have a cheap DIY BL ESC circuit?
Even a constant speed converter will work for my purposes.

Thanks in advance.

proffcharlie
08-23-2008, 02:36 PM
Yes you can use either a wye or delta with a standard brushless ESC. The difference in those two motors is the torque and rpm levels caused by the configuration. A wye usually turns slower and produces more torque and a delta gives more rpm with a slightly lower torque. Remember that this is true when motor factors such as # of winds and # of core plates and strength of magnets, etc are equal.
As for the second question, at one time I had seen schematics in some of these forums and others such as RCU. However, I don't think anybody could build their own for less money than you can buy a mass produced unit. If you have built electronic circuits before it can be done. If you want it to be the size of what is available on the market then you better know and have the equipment to handle surface mount components. If you have these capabilities then look down the index of threads. I think it was in home made electronics or do it yourself electronics. I know the forum was down below the airplane and helicopter groups.

Charlie

proffcharlie
08-23-2008, 02:54 PM
dbcisco,
Just found it go down the group list to General Topics and then to Electronic Builders Workshop. There are a few threads with info to schematics.

Charlie

dbcisco
08-23-2008, 04:58 PM
Thanks.
Most of them are too complicated. I guess I'll have to track down the controller chips for CD and Hard Drives. The have a couple tiny chips driving them.
All I need is a single speed controller IE: a 3phase single frequency generator as opposed to the standard, much more complicated, ESC which changes frequency based on a "servo" type input. Think "Idle up" on a heli and you get the idea.
The standard ones are cheaper and easier to buy than make. What I want isn't common for RC but used in all kinds of electronic equipment esp computers.

proffcharlie
08-23-2008, 06:46 PM
How big, or maybe I should ask, how small of a circuit do you need? A single speed "driver" could be made with a 555 timer circuit producing a pulse with signal driving a set of MosFets. You would just have to establish the PW frequency.

Charlie

dk_aero
08-23-2008, 08:34 PM
555 works for PWM brushed controllers... He's looking for a brushless type (sounds like an off/on vs. proportional controller).

dk_aero
08-23-2008, 09:02 PM
dbcisco,

This maybe what you have in mind...

http://www.rcgroups.com/forums/showthread.php?t=261316

dbcisco
08-23-2008, 09:21 PM
Yes, that is close to what I'm thinking.
As for brushed motors, for my application a simple on off circuit would work.
Basically a brush-less motor is a three phase motor and the speed is dependent on the frequency of the source voltages. Ergo, all I need is a circuit to create 3 voltages 120 degree phased and which I can set the frequency (I have only one speed in mind). I believe that a filtered square wave will work so a quad 555 might do the trick. The quad would leave a timer left over for my on/off timer I need as well.

OK, can anybody see what I am going to do with this? It will be slick if I can do it.

dk_aero
08-23-2008, 10:30 PM
The problem is that you (meaning the controller) needs to know the position of the rotor in order to "time" the 3 phase currents...

A BLDC motor is not an AC induction motor...

dbcisco
08-23-2008, 11:39 PM
Sorry, the BL motors in CD and HD's are little more than tiny three phase induction motors. Of course I've only been an industrial electrician since 1973 so go figure. Position knowledge is only required for either stepping or built in phasing circuits. Get rid of the electronic parts and it is a very basic motor (coils on a stick near magnets):)

dk_aero
08-24-2008, 01:01 AM
Umm... ok... Let's try this again -

In AC induction motors, the rotor turns in response to the "induction" of a rotating magnetic field within the stator (generated by the 120 deg. 3 phase power). Remember this is an AC machine and when the current reverses, so does the generated magnetic field polarity. When alternating current is applied to the stator windings of an AC induction motor, a rotating magnetic field is developed. The rotating magnetic field cuts the bars of the rotor and induces a current in them due to generator action. The direction of this current flow can be found using the left-hand rule for generators. This induced current will produce a magnetic field, opposite in polarity of the stator field, around the conductors of the rotor, which will try to line up with the magnetic field of the stator. Since the stator field is rotating continuously, the rotor cannot line up with, or lock onto, the stator field and, therefore, must follow behind it (slip angle). Since the induced rotor current (and magnetic field) is dependent on the stator field, no "timing" is necessary

In a brushless DC motor, permanent magnets are bonded directly to the rotor, as the current passes through the stator, the poles on the rotor rotate in relation to the electromagnetic poles created within the stator. Therefore, you must need to know the position of the rotor (where the rotor poles are) to know which stator poles to energize (commutation).

In a brushed DC motor, you don't need to know the position of the rotor since the commutation is performed mechanically (commutator and brushes).

http://www.orientalmotor.com/images/in_motion/ac-motor-construction.jpg
AC Motor Construction


<HR>
http://www.orientalmotor.com/images/in_motion/brushless-motor-constructio.jpg
BLDC Motor Construction


A BLDC motor is not an AC induction motor

Sorry...

dk_aero
08-24-2008, 01:12 AM
BTW, you maybe thinking of a synchronous AC motor. This AC motor may have magnets on the stator (field) and the connections to the rotor coils are taken out on slip-rings. The result is called a synchronous motor because the rotor will rotate in synchronism with the rotating magnetic field produced by the polyphase electrical supply.

dbcisco
08-24-2008, 03:38 AM
What ever the proper term, the only difference between it and many 3phase motors (whatever they are called) is that in the little things we use the coil part is stationary and the magnet part moves. The large ones I have used had magnets in the housing and the coils on the turning shaft. Also, it gets more confusing when you get to inrunners and outrunners, just inverts the stator and armature.

Yes I should use "armature" and "stator" throughout but I am sure many would get lost.

Anyway, this isn't geyting me a working circuit small enough to fit a plane.

dk_aero
08-24-2008, 08:14 AM
At this point, I don't think hacking a CD ROM is gonna work for ya'...

Here's a link for a supplier of micro and CD ROM motors and ESC's -

http://www.radicalrc.com/shop/?shop=1&cart=1910153&cat=176&

I'm not sure what your application is, but if you need an on/off type of control (independent of a radio - thinking free-flight), you might want to check into this -

http://www.omegaco.demon.co.uk/mechtml/fmecflyt.htm

Good Luck!

proffcharlie
08-24-2008, 08:22 PM
dbcisco,
If you are looking to use a brushless on either Free Flight or U-Control all of this is a lot simpler. Both of these types of model flying already use BL motors and have controllers to handle the motor speed. What ever your intent is, one sure thing is that you have stirred some interesting uh "discussion".

Charlie

dbcisco
08-24-2008, 09:13 PM
I have rubber powered planes that I would like to put some of the tiny BL motors I pulled from CD drives in. The threads I found on these motors are just rewind and delta/wye changes. Anyway, I don't need speed variation or even control from the receiver, just constant speed.

There are two reasons I wan't to go DIY. The commercial BL setups are too expensive and too big.

I am surprised that nobody has DIYed a simple BL ESC. The few DIY ESC's I've found have 10 times the circuitry as the commercial ones. Oh well, back to the protoboard.

dk_aero
08-25-2008, 02:10 AM
Not sure what size planes you're thinkig of, but here's a couple ideas...

It appears that most everyone is using PIC's or some type of microcontroller to control the drive circuitry. Here's a pretty simple example with the PIC code -

http://home.clear.net.nz/pages/joecolquitt/0hdd.html

If you want to run a certain speed (using a driver circuit alone), you might try something like this -

76374

Not sure about what you mean by expensive or heavy. I'd think that something like this may fit the bill perhaps -

http://www.gobrushless.com/shop/index.php?app=ccp0&ns=prodshow&ref=MICRO5G

Wadda ya think?

dbcisco
08-25-2008, 02:32 AM
The single speed controller schematic is similar to the 555 circuit I was thinking of, really helps the transistors might even be lighter. The planes I am thinking of have 12" wingspans or less. Think of the $2 balsa planes by guillow's and you get the idea.

I refuse to spend $20 on BL motors when I have a shoebox full of them already. A few real tiny ones too! So although the little motor is nice at 9G I really want to use the one's I have. It is the controller that I need to come up with light and cheap.

I don't get the need for a PIC and EEPROM, I don't see them (at least what I can track down) on the commercial ESC's. I bet there is a a special chip or two to A) interpret the servo signal and B) produce the 3 line output (note I didn't call it three phase::o). I also realized that none of the BL's have position sensors, seeing as there are just three input lines and no feedback to the controller. I don't have a clue what the others are talking about. A stepper motor needs it as does a self phasing motor but have yet to see one in any of the commercial motors for RC.

dbcisco
08-25-2008, 03:11 AM
Without using the "3 phase" terms, I found this description of Brushless motors:

" Consumer devices such as computer hard drives (http://radiocontrol.wikia.com/index.php?title=Hard_disk&action=edit), CD/DVD players, and PC cooling fans use BLDC motors almost exclusively. Low speed, low power brushless DC motors are used in direct-drive turntables (http://radiocontrol.wikia.com/index.php?title=Direct-drive_turntable&action=edit). High power BLDC motors are found in electric vehicles (http://radiocontrol.wikia.com/index.php?title=Electric_vehicle&action=edit) and some industrial machinery. These motors are essentially ac synchronous motors with permanent magnet rotors."

Look at this diagram of how a "3 phase" synchronous motor works:

http://www.tpub.com/neets/book5/32NE0444.GIF

Just replace the sine waves with a filtered square waves and you have an RC BL motor.
So, guess I am still an electrician, not retarded.

dk_aero
08-25-2008, 04:08 AM
You're definitely not retarded, and I didn't intend to offend... Sorry... You just need to learn little more about these motors...

You've now shown that you have the phasing and corresponding magnetic fields down. What's now needed to turn the rotor?

dbcisco
08-25-2008, 04:30 AM
What I need is a simple circuit that will output 3 square waves 120 degrees apart and that I can set the frequency with a potentiometer or variable capacitor.

BTW, This method won't work for RC Land vehicles because the motor will only start without a load, OK for flying though.

Seperately, an on/off timer circuit would be nice.

dbcisco
08-25-2008, 04:36 AM
Something like this:

http://upload.wikimedia.org/wikipedia/en/c/c4/3-phase_inverter_cjc.png

dk_aero
08-25-2008, 06:30 AM
Yep, see the .pdf I posted in #34...

BUT!

This is only half (the driver section) of what you need because you have no idea when/where commutation will occur. Sorry Charlie, but you gotta know the rotor position to know which phase to energize when.

dbcisco
08-25-2008, 06:54 AM
Yep, see the .pdf I posted in #34...

BUT!

This is only half (the driver section) of what you need because you have no idea when/where commutation will occur. Sorry Charlie, but you gotta know the rotor position to know which phase to energize when.

The why don't commercial BL motors have a positon sensor?
and why don't AC permanent magnet synchronous motors have them?
Now if you want to start under load in the Large AC motors you need a starter winding to get it to synchronous speed, but not without a load like spinning a prop that has little loading at low speeds.

I don't believe that position sensor is needed. Why do you think it does?

dk_aero
08-25-2008, 07:59 AM
Commercial (i.e., industrial) BLDC motors do have position sensors - hall effect sensors. To rotate the BLDC motor, the stator windings should be energized in a sequence. You must know the rotor position in order to understand which winding will be energized following the energizing sequence. The rotor position is sensed using Hall effect sensors embedded into the stator. Most BLDC motors have three Hall sensors embedded into the stator on the non-driving end of the motor. Whenever the rotor magnetic poles pass near the Hall sensors, they give a high or low signal, indicating the N or S pole is passing near the sensors. Based on the combination of these three Hall sensor signals, the exact sequence of commutation can be determined.

Another method of BLDC commutation is sensorless (which I assume is done by most all RC type ESC's). This method utilizes back EMF to determine rotor position. When a BLDC motor rotates, each winding generates a voltage known as back Electromotive Force or back
EMF, which opposes the main voltage supplied to the windings according to Lenz’s Law. The polarity of this back EMF is in opposite direction of the energized voltage. Back EMF depends mainly on three factors:
• Angular velocity of the rotor
• Magnetic field generated by rotor magnets
• The number of turns in the stator windings
Each commutation sequence has one of the windings energized positive, the second negative and the third left open. During each sequence, polarity of back EMF crosses from a positive to negative or from negative to positive. In ideal cases, this happens on zero-crossing of back EMF. Position is determined by monitoring the back EMF zero-crossing.

dbcisco
08-25-2008, 08:18 AM
Let us suppose that my Towerpro BL motor has sensors. How do they get that information back to the ESC? I only have three leads. Why doesn't an industrial permanent magnet synchronous motor have these sensors?

I would love to believe you but having my Towerpro apart shows no sensors. Please, I am swayed more by explanations and pictures than "its true" statements.

Let me put it another way. The three coils provide a rotating magnetic field in which (around which) a permanent magnet will oppose/attract and thus rotate. So where do the sensors come in?

dk_aero
08-25-2008, 04:00 PM
RC ESC's use the sensorless (Back EMF) method.

dk_aero
08-26-2008, 03:13 AM
Read this:

http://ww1.microchip.com/downloads/en/AppNotes/00885a.pdf

Hopefully this will clear up a few things...

dbcisco
08-26-2008, 03:40 AM
The permanent magnet arrangement in the diagram is much different from what my little motors have. The article shows a NSNSNS arrangement of several magents, mine are single toroidal magnet (NS). The article was informative but still didn't really explain "why" or what happens if you don't use sensors. I am going to try some experiments on these things. At worst I'll fry a couple, at best I'll get something working. BTW if the sensor is an efficiency thing I don't need it. I have some ideas to get this working. Sadly my vacation is at a close so this will have to be worked on after hours at work.

dk_aero
08-26-2008, 04:00 AM
Do you know what brand of motors they are or what brand CD's they came out of? Something like this -

http://www.nidec.com/admmmc/20c24c.pdf

dbcisco
08-26-2008, 04:28 AM
They are from a variety of CD, Floppy and hard drives. I have about 30 of them. Yup, many look like the pics.

dk_aero
08-27-2008, 02:31 AM
More stuff to read... Electric motor articles by Brian Mulder.

http://www.southernsoaringclub.org.za/

dbcisco
08-27-2008, 02:59 AM
"They are a kind of strip magnet that has been magnetized in such a way that they create a number of North and South poles within the strip. "

This makes more sense of the magents I am looking at. Thanks.
Still no explanation of why sensing is needed though. That is what I can't wrap my head around.

CHELLIE
08-27-2008, 05:26 AM
"They are a kind of strip magnet that has been magnetized in such a way that they create a number of North and South poles within the strip. "

This makes more sense of the magents I am looking at. Thanks.
Still no explanation of why sensing is needed though. That is what I can't wrap my head around.

Hi dbcisco :ws: I had a very hard time trying to understand that too, I finally understand it, its interesting to know too, that, not all Blushless motors, will work with all brushless ESC, even though they are rated for the same amps, I guess its the EMFtiming, hall effect or the internal Inductance of the motor, Ask me how I know ;-) I have learned a lot here on Wattflyers, more than I thought I would I would ever know, Take care and have fun, Chellie

dbcisco
08-27-2008, 05:47 AM
I have learned more about aviation in the RC hobby than I did in all my years at Sikorsky. And now am learning things about electric motors that didn't exist (at least rare) when I was an electrician.

CHELLIE
08-27-2008, 10:19 AM
I have learned more about aviation in the RC hobby than I did in all my years at Sikorsky. And now am learning things about electric motors that didn't exist (at least rare) when I was an electrician.

I Agree with you 100% :ws: My Model Aviation Hobby has taught me a lot, and i think its why I Now work as a Tech ;-) Take care, Chellie

dk_aero
08-27-2008, 03:07 PM
Why is sensing needed? Hopefully this should clear it up...

http://www.stefanv.com/rcstuff/qf200212.html

Make sure you fully understand how a brushed motor operates (e.g., how the split ring commutator works and why the "splits" must be at particular positions on the rotor). This is the basis for brushless operation.

We'll figure this out yet!

CHELLIE
08-28-2008, 03:53 AM
Why is sensing needed? Hopefully this should clear it up...

http://www.stefanv.com/rcstuff/qf200212.html

Make sure you fully understand how a brushed motor operates (e.g., how the split ring commutator works and why the "splits" must be at particular positions on the rotor). This is the basis for brushless operation.

We'll figure this out yet!

Thank you dk-aero :ws: for the information, it helps to clear it up even more for me :D I have run into some brushless ESC not working with some brushless motor, even though the amp rating is correct, I guess its about the ESC being able or not to sence the motor, I now try to but turnigy esc for turnigy motors and keep brand names matched, it has worked for me, no more problems ;-) take care, Chellie

proffcharlie
08-28-2008, 10:50 AM
dbcisco,

The basic idea of operation in a BLDC sensorless motor for R/C is that: and this is a simplified version, Phase A is pulsed positive and Phase B is tied to ground, Phase C is not connected to a pulse signal and therefore is off. Because there are more magnets than poles the nearest magnet is attracted to the nearest energized pole. As the rotor turns a magnet will travel pass the "off" pole and generate an induced pulse back to the ESC timing circuit which tells the controller circuit the position of the rotor and the controller will then pulse the next combination of poles needed to continue the rotation of the rotor. The key here is that actually all BLDC motors have a sensor. Some use a separate dedicated sensor and others use the "off" pole as a sensor. Hope that helps.
Now for more fuel on the fire. I'm not altogether sure if a single speed no load operating motor as you propose needs a signal pulse to operate. On the other hand I'm not sure that it doesn't. But as I said before if you want something smaller and lighter than a commercial unit, You need to know how to handle surface mount equipment.
Try checking out the equipment available through "Shorty's Basement" (www.shortysbasement.com) or Atomic Workshop (www.atomicworkshop.co.uk). You might try checking the AMA web site for info on Free Flight modeling for links. What your trying to do with the motor is already being done and Free Flight Modelers are always concerned with lightweight equipment.

Charlie

dk_aero
08-30-2008, 06:46 AM
From what I understand, most free flighters use small brushed motors. This keeps the motor controller light and simple... Also allows for easier/simpler use with timers/timing circuits (some have the motor controller and timer all in one).

http://www.microflierradio.com/Timers.html