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Author Topic: Electric Motor Classification  (Read 40013 times)

BreezyB

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Electric Motor Classification
« on: July 17, 2008, 02:59:23 PM »

Being quite new to electrics , can someone please explain what motor type numbers mean ( i.e 380, 450, 600 etc etc).
Many thanks,  O0
Barrie.
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Ghost in the shell

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Re: Electric Motor Classification
« Reply #1 on: July 17, 2008, 05:06:32 PM »

measure the length of the motor, I was talking to the guy at Mobile marine, he mentioned that MFA call the 380 motor the 380 because its length is 3.8cm long. 

a 5 at the end of the designation, (545), (385) etc also indicates a 5 pole motor
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andrewh

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Re: Electric Motor Classification
« Reply #2 on: July 17, 2008, 05:20:43 PM »

BreezyB

The simplest question, but not very a simple answer.  Even the brief answer involves history, inflation and hijacking!

Originally they were Mabuchi designations, and I understand, but could be wrong, that they represented the armature stack length in mm.  The older ones (380, 540, 550) had that meaning.

At some point the 0 on the end came to mean 3 -pole (relatively high speed) and a 5 got tacked on the end to represent 5 pole (relatively high torque, lower speed), so 545 and 385 are 5-pole variants (very boat-friendly)

Have a look on the Mabuchi website - a good deal of history is still in there, I think.  designations like 120, 130, 180 still exist under the old meaning.

None of this, you will notice, tells you ANYTHING about the windings inside and hence the speed, current and voltage range.
It is worth bearing in mind that all the motors can be wound from 1.5 Volt windings (2 turns of coat-hanger wire) to 36 or 48 Volt winding - millions of turns of maidenhair wire.

After Mabuchi comes the hijackings and rampant inflation, and the first attempts to describe the windings

To be continued (if it of any interest)
andrew


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Colin Bishop

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Re: Electric Motor Classification
« Reply #3 on: July 17, 2008, 05:37:38 PM »

I think a lot of people might find it interesting Andrew. There have been many posts about specific motors and their suitability but not a general overview of the subject - well, not recently anyway!

Colin
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Martin [Admin]

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Re: Electric Motor Classification
« Reply #4 on: July 17, 2008, 06:02:19 PM »

"To be continued (if it of any interest)"

Yes please!

Martin  O0
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BreezyB

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Re: Electric Motor Classification
« Reply #5 on: July 19, 2008, 03:45:44 PM »

Once again, thanks to all for your advice. :)
Coming from sail to electrics has become more of a learning curve than I expected. And, although most plans or articles specify a suitable motor/ESC and battery combination which makes it easier, I would certainly be interested to know more. So, I for one, echo Martin's "Yes Please" to Andrew.
Regards
Barrie.
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Shipmate60

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Re: Electric Motor Classification
« Reply #6 on: July 19, 2008, 05:35:25 PM »

As posted some while ago.
Good info when you wade through it.

http://www.mabuchi-motor.co.jp/en_US/technic/index.html

Bob
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nightowl2912

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Re: Electric Motor Classification
« Reply #7 on: July 20, 2008, 10:53:54 AM »

Hi all,
i was looking for some info on a motor and found this don't know if its any help

http://offshoreelectrics.com/motocalc_motor_table.htm

Andy
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andrewh

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Re: Electric Motor Classification
« Reply #8 on: July 21, 2008, 08:58:59 AM »

Mayhemmers

Sorry to offer and not immediately deliver - busy weekend

I aim to continue during my lunch today - meanwhile I found a few useful bits of the Mabuchi site:

 http://www.mabuchi-motor.co.jp/en_US/technic/t_0302.html
Motor designations and their meanings

http://www.mabuchi-motor.co.jp/en_US/technic/t_0300.html
Motor types and brush gear

http://www.mabuchi-motor.co.jp/en_US/product/p_0305.html
Typical motors for different applications

http://homepage.ntlworld.com/edward.matthews/ddmbc_files/motors/mabuchi.htm
This lists the (good old) Mabuchi range as sold by Como Drills with outside dimensions
It may be worth knowing that in this list the RE120 has metal brushes - so its life when used for high currents (for example - electric flight ) is very limited. But its very cheap too.

More soon - "the meaning of Turns"; Inflation in Motor names; what is the meaning of 6V? and much, much less
andrew


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andrewh

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Re: Electric Motor Classification
« Reply #9 on: July 21, 2008, 01:08:47 PM »

Brief bio details – since it may explain where I am looking from
Engineer:  Age:  fifty-mumble.  I have been flying with r/c since 1963 and flying electric since 1985 when it was at a fairly early stage.  Model flyers were avidly borrowing buggy motors and learning what worked, what was too soft to fly, and what let smoke out!

So here we are in the mid 1980s with a view of the sizes for the Mabuchi range, but very little idea about what they do since there is no winding or brushgear information in the bare motor size.

Enter the buggy crowd.  They run (I understand) 5-minute races, and always on 6 cells (the old sub-C 1200MAH nicads were the first rechargable cells which could take the current drain).  They also use(d) 3-pole 540 motors exclusively* and developed ways of describing the windings by the number of turns of wire in one pole slot.

*Yes, there were some Astro car motors with 7-pole skewed-armature motors.

Since a pole slot has a fixed area you can fill it with a few turns of thick wire, or hundreds of turns of fine wire.  I hasten to add I’m not an expert, but the early electric aircraft motors were described by “turns” as well,, since they also ran on 6 x 1200 cells, and were often aimed at 5 minutes of motor-on flying.

So less turns is a thicker wire, lower resistance, more current, more revs – a “Hot” motor and more turns the opposite.
My Dick Edmonds flight motor was, I think 21 turns, and was a soft and pleasant direct drive motor for a 6 foot electric soarer.  “Hot” buggy motors might have 17 or 15 turns or less.  (Double and Triple winds just mean that instead of one thick wire the armature is wound with two or three thinner wires all paralleled together (which pack and wind more easily in the space).  So in theory double winds can pack slightly more copper into the same space.

So that is “turns” It has a real meaning for car motors on 6 Nicad cells – what about now?

A) Well; last time I bought a Mtronics ESC all the ratings were described in “turns”  EG:  the Marine 15 is suitable for not less than 15 turns at 7.2 volts.  This may be now out of date, and I did somewhere find a translation of this into Amps continuous, but how quaint and confusing especially when buying for a boat.

B) If you follow any of the discussion about brushless motors the same issues of how many turns of what size wire comes up, especially if you wind your own CD-ROM brushless stators.

However science has come to our aid in the mid 90s and all motors, both brushed and brushless are, or can have, their characteristics described by Kv.

Next:  Graupner and the "Speed" range

andrew
Please tell me if this is too light, too heavy, rubbish or marginally interesting
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Martin [Admin]

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Re: Electric Motor Classification
« Reply #10 on: July 21, 2008, 03:11:31 PM »


Hi Andrew,
Excllent stuff!

So does a "turn" roughly equate to 1Amp as a Mtroniks Marine 15 handles 15Amps?
Also is there a chart showing current 'over turns ''over' Revs? (Or something like that!)

As you will be covering Graupner "Speed" motors next, can you please tell me what the BASIC
differences are between:?

Speed 500 ECO RACE 7.2v - RACE 7.2v   - BB RACE VS 7.2v - 1E 2v 6-12v   - SR RACE 8.4v - SP 8.4v - BB SP 8.4v

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andrewh

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Re: Electric Motor Classification
« Reply #11 on: July 22, 2008, 09:41:47 AM »

Martin,

Sorry, no or more accurately NO it doesn't
As the turns go down the current goes up, so they could only coincide at one point
 
In fact the Marine 15 is meant to handle 10A cont (I am going from memory I am afraid) Sadly I am hitting it with two S400 6V equivalents which would pull 10A each if agressively loaded.  It works, but splutters - which must be the overtemp cutting in.

But my 20 turn EMP flight motor did pull about 20A on a 7x 6 - coincidence I'm afraid
Speed motors and Kv today

I can't clarify from my own knowledge the motors you mention, but we can tease out the essence, I'm sure

andrew
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andrewh

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Re: Electric Motor Classification
« Reply #12 on: July 22, 2008, 01:34:02 PM »

The Speed saga
I don’t remember when the first “Speed” motors appeared – probably the mid 1990s.  Basically Graupner observed the chaotic motor naming and supply scene, and decided to make it simpler and better, and they did!

They introduced a range of propulsion motors which covered most of the perceived requirements (at that time).  I believe that the aim was electric flight; and this spins off into fast electric boats (rather similar requirements),. 

Inflation strikes!

The first sizes introduced were the 380 and 550 sizes, and these were christened Speed 400 and speed 600 respectively.  They were well made, they all sported built in capacitors(between the terminals) and they all had internal brushgear and metal end-bells.

I still don’t know if Graupner picked existing motors from the manufacturers range or had them made specially in sufficient quantities (when Derek Knight ordered the KP01 motor he had to purchase 10,000 at a time).  I lean towards the first view since some of the Speed motors that followed are distinctly weird, and not what a logical German commercial organisation might have defined!

It is a characteristic of the Speed 400s (and some of the other sizes) that they have a number attached to them (e.g 6V, 7.2V).  It is permissible to take this as a normal operating voltage, and you won’t go wrong in doing so. 
In fact it is a signal rather like the “winds” which indicates the size of the wire and number of turns – for example the S400 4.8V is a serious ratmotor with 3 turns of fence wire and is capable of devouring its brushgear if loaded too highly.  The S400 7.2 V is a mild motor wound with finer wire and will tolerate overloading and slow operation more calmly.  But many people run a S400 4.8V at 7 volts through a big ratio gearbox which allows it to spin fast with reasonable load .  I run a S400 6V on 10 nicd cells (12V nominal) in a ducted fan and it still works after 20 runs or so.

1.   So the sequence of events goes like this:
2.   Graupner introduce the speed motors
3.   People try and fry and publish “what works” tables ()
4.   Graupner introduce variants, more sizes
5.   People try them and fry them and publish “what works” tables (
6.   goto 4

The variants now include “Eco”, “Race”, “BB” and “Torque”  and frame sizes from 280 (parkflyers) to 900 with a lot of fill-in sizes as well (http://homepage.ntlworld.com/edward.matthews/ddmbc_files/motors/graupner.htm).  The initial range were all ferrite motors, and competitively priced, but now the range includes Neodymium versions – with rare-earth magnets.

The Voltage descriptions are still just a recommendation for normal voltage if used as Graupner intended.  If you run a “7.2V” S600 direct drive on a tug propeller on 7.2 V you will become quickly familiar with SpeedSmoke.  It might work well on 3.6V in this application!

Speed Summary
http://www.alansmodels.com/main_site/engines/motor_graupner.htm
This list gives the shaft sizes, etc - this needs a little careful reading since similar motors can have different fixing sizes and shaft sizes
Intended for electric flight, and for high revs in carefully controlled loadings, so translating into boats takes some care.  All of them (I believe) are 3-pole motors; some of them have staggeringly high Kvs (speed 300 especially, and I would suspect, the Race versions)
Use them for high speed boats, geared boats and air boats
Don't let them slow down and slog
Start with little props;  work up in size till the motor glows then go back 2 sizes



Odds and Sods
While rambling down memory lane a couple of possibly relevant points come to mind:
1)   YOU can rewind ANY motor to suit ANY voltage and load.  Fact, quite easy - you have to be able to solder and count to about 30
2)  Americans (and others) started christening electric motors by the glow Motors (in Cubic inches) they were supposed to be able to replace - so the 540 size is still refereed to as the "05" class in the US.  Astro flight still label their brushed range this way - and they don't lie.
3) There has been intense discussion about direction of rotation and timing of all the Speed motors - and it applies to all electric motors as well. 
The best have variable timing  - ALL can be adjusted to suit the application. 
I THINK that the Speed range come neutrally timed - this means that they are incorrectly timed for either direction of rotation and any load and speed!  There has been much published on adjusting the timing - a typical spiel is attached.
http://www.ef-uk.net/data/speed600race.htm

I go now to get an ice pack and research what Martin's alphabet of letters means!
Comments, additions, refutations welcomed
andrew



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andrewh

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Re: Electric Motor Classification
« Reply #13 on: July 24, 2008, 01:31:05 PM »

Two things today!

One - Martin's alphabet soup
I set out without knowing very much about the differences, and I'm not sure yet that I do - but here is what I have found so far:
Table of the meanings of Graupner desctiptions - ECO, BB etc and data for the specific motors Martin mentioned

http://www.zuk.modelarstwo.org.pl/mtrdata.pdf
This site is where some of the data and explanations came from - there is a lot of good formulae and data in it for SP600s and 500s

Sorry that's as far as I can go on SP500s - I could pick one for a plane, but can't help more for a boat
But why would you?
I suspect that brushed motors will vanish in 2 or 3 years - replaced by brushless - for which you need to understand the turns (!) Kv and arcane motor  sizing data ;D

Two:  Barrie
I have rambled off into the distance - was any of it anywhere near what you needed?
Is there a boat you are planning or already selecting a motor for?

andrew


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BreezyB

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Re: Electric Motor Classification
« Reply #14 on: July 27, 2008, 05:56:01 PM »

Wow!!!!  :o  Well I did ask didn't I !!!!!!. Seriously, Andrew and all contributors, I am most grateful for your comprehensive answers to my original question. I have trawled through all the text and site links suggested and although I will admit to not quite understanding all of it I have printed off a good deal of it to digest at my leisure, probably during the winter months backed up with a stiff drink.
In basic terms, some of the tech explanations go some way to understanding the complexity of small electric motors but for now , as a "newbie" in this area, I will stick to motor/ESC/Prop recommendations until I feel more adventurous. Thanks again to all Mayhemmers for your help.
Regards
Barrie.
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BreezyB

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Re: Electric Motor Classification
« Reply #15 on: July 27, 2008, 06:15:37 PM »

Sorry Andrew , to answer the question in your last posting. Yes I am planning to build something relatively straightforward for club steering events and I quite fancied the Higgins Hellcat PT Boat which was a free plan by Glynn Guest in Model Boats Mag. Glynn finally used a 540/5 motor through a 2:1 gearbox. I have no problem with following his suggestion but it just made me wonder what is a 540/5 motor ? and why some options were unsuitable etc etc.?  Well now I know!! or at least I have an idea. O0
Thanks
Barrie.
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andrewh

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Re: Electric Motor Classification
« Reply #16 on: July 30, 2008, 12:57:12 PM »

Barrie,

Welcome to the Hellcat club!  Glyn posts here (he is GG) and is very helpful.

If you have the MB article he describes why and how he finished up with the motor he finished up with - the initial 3-pole motor - which I seem to remember was a fairly hot motor was taking too much current and didn't take well to the speed controller so a milder, lower speed 5-pole left the speed acceptable and took more kindly to low speed operation (Glyn, I believe takes part in steerring competions)

Following his experience will get you grinning quickest!  so if you start with the gear ratio and prop you are liiking for a motor of similar type - so go for the same, if you can or maybe one of the ECO S500 or S600 motors - these are pretty soft 3-pole motors. 

Have you met this thread about the Hellcat started by Glyn?
http://www.modelboatmayhem.co.uk/forum/index.php?topic=8783.msg112060#new

Please keep us posted on your progress
Remember nothing is cheating if illustrated by pictures!
andrew

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BreezyB

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Re: Electric Motor Classification
« Reply #17 on: July 30, 2008, 04:14:02 PM »

Hi Andrew
I'm so glad that I mentioned the Hellcat Project. Your additional information and the Utube link is just the "icing on the cake" and the sound of those engines, well, sort of gets you going "don't it". Inspired by your motor info and the link to Glynn's previous Hellcat posting I'm quite looking forward to getting stuck in and will enjoy my first step into scale electrics.
Thanks again for your detailed and informative reply.
Barrie.
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Garabaldy

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graupner motors table
« Reply #18 on: September 10, 2008, 08:27:11 AM »

sorry if this is a repost but this is quite usefull.

http://homepage.ntlworld.com/edward.matthews/ddmbc_files/motors/graupner.htm
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BreezyB

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Re: Electric Motor Classification
« Reply #19 on: September 12, 2008, 12:02:14 PM »

Thanks Gb, I have already come across this chart in my quest for motor knowledge. However it was good of you to take the time to bring it to my notice. It is much appreciated.  O0
Many thanks
Barrie.
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rathikrishna

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Re: Electric Motor Classification
« Reply #20 on: December 21, 2010, 06:10:33 AM »

Thank you respected Friends...its a helpful article..so i got even more good idea to alter my toy motor from mere 3 volts to a high rev hightorque again...great posts....thank you...once again...
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Captain Flack

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Re: Electric Motor Classification
« Reply #21 on: January 06, 2012, 04:52:41 PM »

Is there anywhere that gives a comparison between a brushed motor of say Graupner 540 and its equivalent in a brushless motor?  Brushless appears to be the way to go but I get confused enough with the "old" style motors :-)
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Subculture

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Re: Electric Motor Classification
« Reply #22 on: January 06, 2012, 07:09:05 PM »

When comparing with brushed counterparts, I tend to look at the RPM of the motor (stated in KV, which is RPM per volt) and the wattage.

540's come in many different flavours, but a standard Graupner 7.2 volt Speed 500 is about a 2000KV motor and around the 80-100 watt rating.

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Re: Electric Motor Classification
« Reply #23 on: August 11, 2012, 06:32:17 PM »

On mabuchi motors RE are low power RS high power motor's.
In the very early days of fast electric racing the 540 RS was the motor for it`s class.
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malcolmfrary

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Re: Electric Motor Classification
« Reply #24 on: December 18, 2012, 10:42:12 AM »

An extra question - is there a definitive list anywhere giving equivalences for the Graupner range?  I have always managed to get lost in the world of decaperms, hectaperms, monperms etc.
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