MORE POWER AND SPEED FROM ELECTRIC MOTORS

[Dietrich]

Hi Guys,
Recently I remembered a trick that I used many years ago to make electric MOTORS go FASTER.
Now I am not absolutely certain that the Heng Long circuit boards will support this idea,but as we all run cooling fans I will carry on and be prepared to be told that it is risky/wrong/silly/or any other comments that people care to add
Basically it is an extremely simple way to make all our motors SPIN FASTER and produce more POWER !!
I have looked around on the internet and have FINALLY found a demo video to show you what happens when you attach NEODYNIUM (Rare Earth Magnets) to the outside of a conventional electric motor, follow this link and you will see what I mean... http://www.wonderhowto.com/how-to-incre ... 6453/view/" onclick="window.open(this.href);return false;

Our Heng Long Tanks all use brushed DC Electric Motors. Inside the motor case amongst other bits that make it work are 2 permanent magnets which are curved in shape to fit inside the circular case and allow maximum space for the armature

Ferrite magnets as they are positioned inside our motor cases..

motor8.jpg (14.19 KiB) Viewed 5328 times

Magnets removed from case

motor9.jpg (17.76 KiB) Viewed 5328 times

The magnets have their poles on the inside and outside of the curves,one will be North on the inside and the other will be South on the inside so that the motor actually works. The location of the two different magnets can been ' seen' from the outside by where the two slots are cut in the casing and are held apart and against the slots by the' U- shaped' metal wire clearly visible in the image above............................................
NOW you need to concentrate on this bit .....and have 4 Neodynium magnets to hand......
..............the super strong NEODYNIUM magnets need to be added to the casing so that the opposite sides are together that is .... NORTH to SOUTH and vice versa. You CANNOT just guess by placing the magnet on either side of the case as the NEODYNIUM magnets are SO STRONG that they will overcome the weak magnets in the motor and stick to the metal case regardless of the poles ! and we want the magnets to ADD together to be as strong as possible !
Opposite poles attract and like poles repel...so the North pole of the NEODYNIUM goes against the SOUTH pole of the OUTSIDE of the motor and the SOUTH pole of the NEODYNIUM goes against the OUTSIDE of the NORTH pole of the motor. This may seem odd but the two magnets now work as one, so we have a MUCH increased magnetic field inside the motor case.( The magnets add their fields together, like putting two 1.5 Volt torch batteries together, positive to negative, you end up with a 3 volt output ... 1.5v + 1.5v = 3VOLTS ).
Try it out for yourselves, get a motor find out which side is North and which side is South and mark the case accordingly .....start the motor running by attaching the power leads directly to the battery. NOW comes the good bit add first one and then the second magnet to the correct sides of the case and you will notice an immediate increase in speed of the motor !.....now remove the magnets and the motor slows back down again.... Exactly like the video ....
I will attach a few diagrams and texts to show that the idea SHOULD work, in THEORY as well as obviously in practice.......Unfortunately you have to click on these diagrams to make them clear enough to read. BUT basically the strength of the Magnetic field DIRECTLY effects the torque and speed of the motor !

Theory image 1

Theory image 2

Theory image 3

Theory image 4

Theory image 5

The mathematical formula shows that it works in theory and supports the practical tests..........BUT.....I think that it may also draws more current from the battery through our Heng Long Circuit boards......which I believe are rated to a 3 AMP continuous current. I did a test using a 3-1 reduction gearbox I counted the revolutions of the track-drive sprocket and without the magnet it was 96 rpm and with the magnets it was 114 rpm.
Now I need an expert to tell me if there IS an increase in current drawn AND IF the Boards can handle this increase without burning out ! It may also be worth putting another cooling fan to blow onto the motors as they are being 'Over-clocked' or 'Super-charged'-----you choose what to call it

[Dietrich]

Come On Guys....
Someone must have tried this, looked at the 'Maths' or at least have an opinion that they want to share........I already had my magnets, I bought them from http://www.first4magnets.com/index.asp" onclick="window.open(this.href);return false; and am planning to use 2 ..F4317N and 2..F4317S ( 2x NORTH 2x SOUTH )
Regards :~
Alb.

[Saxondog]

I must be loosing it,I down loaded these pictures and then viewed each one and understand the theory,what I see may be an issue is friction heat from the increased RPM,and the effect on the shaft bushings? They were designed based on the values of the magnet strength,so if you increase the magnets force on the armature then what happens to the shaft bushings? Will be interesting to find out. Blake

[Dietrich]

Hi Blake, :~ Thanks for the reply,
I must admit that the bearing issue had crossed my mind, and running the motor on its own it REALLY does rev ! ,so I put a bit of oil on each end, to help the bearings.
I am working on the assumption that with the motor in its correct 'position' in the gearbox and moving a heavy tank around it will reduce the revs to a 'Safe Level', also how long do we run actually run our tanks constantly at full speed ?
From what I have read ,I am certain that electric motors are really robust and can take a serious amount of abuse without harm, the fan should keep them cool and if necessary I will add a duct / funnel to direct the air into the motor vents!!
At the end of the day , I am using the 'Metal capped' new Heng Long motors,which came with the metal tracks and sprockets that I bought, and I had planned on replacing them with ...Jamara LiPower 480 HS BB Electric Motors....so if I burn them out it does not really matter.......
As a side issue I have a 4 wheel drive off road car that I bought from Ebay for 99 pence ( 99 cents effectively ) It should run a weak 6 volt re-chargeable battery pack,but it was useless so I simply put my 1700Mah Heng Long 7.2 Volt battery in it which is 3 times the size as the old battery pack.............NOW it runs properly and at speed with no damage to the electrics or the motors,although I have just added a fan as they were getting rather hot
This also makes me wonder that if a 6 volt model can run safely ( For the last year ) at 7.2 Volts without ANY form of COOLING an increase of 1.2 Volts......then CAN our Heng Long boards run safely at 8.4 Volts, also an increase of 1.2 Volts ?? especially as we ALL run at least 1 cooling fan. I have seen the 8.4 Volt battery packs, on Ebay and they are simply longer than our standard packs by 1 battery ;that is, they have 7 x 1.2 Volt batteries rather than our 6 x 1.2 Volts
I hope that an 'electronics wizard' can look at both the Magnet and the 8.4 Volt issues and put forward an expert answer....I will certainly run the Magnets and see what happens to my tank as the Torque also seems to be dramatically increased.. .....and if the speed is too high then just don't move the levers all the way on the Transmitter
Regards,
Alb.

[Saxondog]

If you would like to try 480speed motors I have two from Graupner I never used,new in the box.Perhaps when I send over the parts you need I could send the motor as well.This idea of the magnets increasing the power is interesting,I wonder about the low-end torque they will produce? Cheers Blake

[mickyb]

Hi Guys,

may I add another bit of info.

In my yoof I used to race 1/24 th scale slot cars. Sometimes we raced over a 24 hour period to mimic the Le Mans race itself. We tried all sorts of devious tricks to get an extra second a lap just like the F1 manufacturers today.

Eventually we tried and settled on a simple trick. This works with 3 pole or 4 pole motors, cans or open frame types.

With can types, to increase torque.....reduce the airgap between magnets and commutator coil assy.
Carefully open up the can lugs and remove the end cap containing the brush assembly/bearing cap etc.
Remove the commutator/coil assembly to reveal the can and magnets.
Mark the magnets so you can replace them in the same position then remove them.
Now place a very thin shim of magnetic material against inside of the can and replace the magnets. This reduces the airgap between magnets and commutator assembly when replaced.
For the shims we used the thinnest feeler guage material that we could get from the local DIY motor maintenance shop.

To increase revs.....

Be careful here, and only MINIMUM adjustments are necessary...think nats whisker movements.
Remember which way the motor rotates in FORWARD motion.
As above, strip the motor.
Hold the commutator shaft in a vice without marking the shaft.
Wrap the armature assy in very fine emery/wet and dry, grip armature with mini pliers and gently rotate the armature on the shaft a VERY small ammount in the direction of rotor travel. This will ADVANCE the magnetic effect of the armature/coil windings as the armature rotates to the brush set/magnets.

The motor won't like running slowly if you rotate the armature too much, but as you use 3 to 1 gearboxes and don't crawl around with the motor just about rotating you should get a decent increase in revs at the top end.

With open frame motors just wrap a 1 mm feeler guage round the coil assembly and crimp the frame in a bit.
until you have reduced the airgap, then advance the armature assy as above.

NOTES.
The coils will be tight on the formers and you only get a nats whisher of slack where the coil wire is fixed to the armature so armature rotation needs to be minimal on the shaft.
Re winding motors is easy and you can get coil wire at a good model train shop.
Increase the wire Diameter and reduce the number of windings to get torque and revs.

This is food for thought and if you want to try it, be careful with armature movements as breaking the wire where it joins the armature means you have to rewind the coils.

Have fun

Mike

[Dietrich]

Hi Mike :~
Thanks for the input, I think that your' Moving the magnets closer to the armature trick' is basically the same as my Neodynium magnet trick.....they both increase the magnetic field acting on the armature and so increase Torque and Speed.
If you haven't tried the Neodynium magnets ( with the poles in the correct alignment !).....then please try it.....It really is ABSOLUTELY INCREDIBLE ....the motor just 'Takes off' and> Revs -Its-Nuts-Off<
Interesting about advancing the motor to make it rev higher !....I had read that but have not been brave enough to try it ....I have also just seen about the Increase in wire Diameter and reduce the number of windings to get torque , BUT the article said it would have LESS revs ?.?......SO... since you used to race electric cars does it work that if I took it to an extreme ......and I stripped ALL the fine wire off the armature and replaced it with 1 or 2 Turns of solid core household grade copper wire that it would have Massive Torque or is there a limitation beyond which the motor will not work ?
Regards, :~
Alb.

[mickyb]

Hi Alb,
in theory you are correct. I doubt anyone would go that far because you would need one heck of a voltage to get the flux high enough to turn the coil.

We used to use coil wire about twice the thickness that was wound on the coil by the manufacturer. So we would double the guage.

This was all 40 years ago, so I expect the motor manufacturers are making motors that are as efficient as can be made these days. But we should remember that they are making an average motor for a spread of uses and expect gearboxes to deal with power transfer and needs. This is why there are so many "Mabuchi" style of motor out there today. Just look at the number of motors Graupner make today, there must be one to suit the job in hand.

I will certainly try the external magnet idea in a speed boat I have nearly completed, so thanks for the valuable info.

My input was meant as a bit of history and the oportunity to try a cheap fix not an alternative to your modern take on a motor mod.

All the best Mike

[Andy in Cheltenham]

Years ago I used to work for Beatties and we sold RC cars, that was my bag then. People used to come in and cry when I told them the price of better motors. I said give me you current one and for a fiver I'll make it faster. Next day they would return with said motor and a fiver. I took the thing home and off the plastic end cap and then removed the magnets. I took a small hacksaw and made to more lugs on the can so that I could rotate the plastic end cap a little bit. I then spaced out the magnets so they were closer to the armature. I put the end cap back on in its new position and hey presto more speed in one direction and slower in reverse. The only thing this changed was the running time from the battery, it was a bit shorter. I never had any complaints about my work. We didn't sell many upgraded motors while I was there (bad boy).
I used to wind my own armatures too, but could not find hi temp solder for the terminations. the solder I used just got hot and spun off.

Andy

[mt 1]

thats a old mod i used with my 1/32nd slot cars/tamiya rc cars is it worth trying on the heng long tanks
thanks Andy you jogged a few old brain cells with that mod.