Motor Upgrade

[Boxerlego]

"power output: 5.71 Watts"

NIIIIIICE!

At maximum efficiency

How did you choose this motor?

There's a whole range of them at the mabuchi website.

Including this one: 50mm x 36mm excluding shaft, no-load rpm 23,400 at 9.6V draws 1.4A. Stalled torque 21 N.cm draws 57A (!). Draws 9.5A at max efficiency, outputting 65W. About US$10.

Go big or go home, I say

In order to get started on picking a motor I first had to figure out how fast the RPM on the XL "motor" is to give me something to compare to. I pick this motor because it had the same 2mm shaft for the pinion and operated with in a 8-16 volt range. This is the motor that got replaced.

[Boxerlego]

Here is the frame I made to lock the motor in place with some epoxy known as JB weld. This is the most delicate and sensitive part, It requires patience and understanding of the JB weld. Note that there are magnets inside the motor and

show what happens when magnets are close even the dried epoxy is has magnetic attraction. So I broke the lift arms of the previous motor to use on this motor. Because those two lift arms already had dried epoxy that saved a day. All I had to do was file down the dried epoxy so the motor and the gearbox fit together evenly. Having the pinion gear on the shaft and connecting it with the gear box made locking the motor in place a little less difficult then having no pinion gear. The most critical aspect is centering the motor shaft and securing it to prevent any movement when applying the liquid epoxy. I used a very little amount of epoxy here so that the motor magnets cant pull to much epoxy in. Now that the epoxy has dried up and locked the motor in place with the liftarms I will do some test. I will also make some pf wire wire connections. One of the benefits on this motor is push in terminals.

Edited January 22, 2013 by Boxerlego

[Boxerlego]

[allanp]

WOW, that's pretty outstanding and an substancial improvement.

[jadedomg]

Wow that is great. I might have to learn how to do what you did to that motor just so I can have a kickass lego RC car !

[Boxerlego]

WOW, that's pretty outstanding and an substancial improvement.

Thanks! I am amazed myself at the improvement the motor made. Even though it is geared 6:1 there is some torque behind it, I was able to climb over little ledges and a pile of garden hoses.

The XL motor geared 6:1 could not even do that.

Wow that is great. I might have to learn how to do what you did to that motor just so I can have a kickass lego RC car !

Thanks for your interest. There are a couple of things that must be understood in order to make the lego motor upgrade happen.The hardest part is the epoxy part. Get some JB weld and mix a little up and get a idea on how to handle it. I use a toothpick and one fact is the ability to put the toothpick inside the holes on the lift arms and apply epoxy inside there. Getting the brass pinion gear off the motor is very easy to do, gravity and fire do all the work there. However putting on the brass pinion gear is the complicated part. I will refine this and detail it out for all to know what I did here. Taking apart the XL motor case is easy when you break the clips off. If you want to do this I would start by improving the XL motor by connecting the planetary sets together and get that perfect then move on from there.

[jadedomg]

Thanks for sharing, I dont have steady enough hands to do most of this but could find a volunteer. I do like that you used the XL housing to keep everything close to lego as possible while pushing everything beyond the limits lego intended :)

[Boxerlego]

Thanks for sharing, I dont have steady enough hands to do most of this but could find a volunteer. I do like that you used the XL housing to keep everything close to lego as possible while pushing everything beyond the limits lego intended :)

No problem, Upgrading the motor is not exatlly hard but rather long. Yes there are few parts that require that special touch and delicate hand. Using the XL housing will make for a better axle alignment at higher speeds than a axle-connector JB welded directly to a motor shaft. Thanks again.

[Taiphun]

540 size cans are the standard in the R/C world. 380 sizes are a little bit smaller, you can get them from any RC shop.

Different windings and voltages will yield varying amounts of torque/speed. I should get find me a motor and crack one open.

[sshamsi]

This is the motor that got replaced.

Boxerlego, I am really interested in trying out this mod. I had been searching for the buggy motors 5292, but could never justify shelling out $50 for a used motor from half a decade ago. However, regarding the motor you linked to in the quoted post, is that the original XL motor or the motor which you tried out in your first mod? I understand that in your later posts, you replaced that motor with this motor, correct?

Also, unless I am missing something, I assume you retained the original gearing of the XL motor?

Thanks!

[rm8]

Ohh sh$t!!!:) what is the gear rate after xl orange hole output?

Edited January 24, 2013 by rm8

[Boxerlego]

540 size cans are the standard in the R/C world. 380 sizes are a little bit smaller, you can get them from any RC shop.

Different windings and voltages will yield varying amounts of torque/speed. I should get find me a motor and crack one open.

That is interesting.

Boxerlego, I am really interested in trying out this mod. I had been searching for the buggy motors 5292, but could never justify shelling out $50 for a used motor from half a decade ago. However, regarding the motor you linked to in the quoted post, is that the original XL motor or the motor which you tried out in your first mod? I understand that in your later posts, you replaced that motor with this motor, correct?

Also, unless I am missing something, I assume you retained the original gearing of the XL motor?

Thanks!

That is awesome sshamsi! That motor that got replaced was a early prototype. Yes that is correct. The replacement motor also has two version PC and SC, I used the PC. The planetary gear box has been change to a 6:1 ratio as well. I have not even tested this motor out with the original gearing 36:1.

Ohh sh$t!!!:) what is the gear rate after xl orange hole output?

It is fast but still can be faster. The gear rate from the orange hole output to the wheels is 4.2:1. All 4 wheels have power from the single motor drive.

[Boxerlego]

I finished making the motor wire connectors. I used two electrical connectors with the fork terminal to connect with the push-in terminal on the motor. I strip a Lego extension wire and solder the ends. I bent one of the forks on the electrical connector over on the black wire locking it down. Then I wrapped the exposed wire over the fork terminal and solder everything up. I connected the fork terminals up to the motor and then I put some JB weld on it securing everything in place.

Edit: I forgot to add a capacitor. I should have connected the capacitor up before the JB weld part.

Double Edit: I've finally connected the up Decoupling Capacitor to the motor wire.

Edited April 21, 2013 by Boxerlego

[sshamsi]

I finished making the motor wire connectors. I used two electrical connectors with the fork terminal to connect with the push-in terminal on the motor. I strip a Lego extension wire and solder the ends. I bent one of the forks on the electrical connector over on the black wire locking it down. Then I wrapped the exposed wire over the fork terminal and solder everything up. I connected the fork terminals up to the motor and then I put some JB weld on it securing everything in place.

Edit: I forgot to add a capacitor. I should have connected the capacitor up before the JB weld part.

Thank you for the updates boxerlego!

I am keenly following your posts, however, I am curious, what sort of capacitor would you have used before connecting the motor wire connectors?

[kieran]

do you know the motor that was in the original XL motor?

[Boxerlego]

Thank you for the updates boxerlego!

I am keenly following your posts, however, I am curious, what sort of capacitor would you have used before connecting the motor wire connectors?

Good question. I would have used a 104 .1uf 50v ceramic capacitor. This capacitor is known as decoupling capacitor and is connected in parallel with the dc motor. Having this capacitor will increase the commutator and brush life on the motor.

do you know the motor that was in the original XL motor?

No, I don't know the motor that was in the original XL motor.

Edited January 28, 2013 by Boxerlego

[Boxerlego]

I have taken apart the previous custom motor and the XL motor so I can check everything out and compare the two. It was a some what destructive process to get both the motors open and not as easy as others can be. The first item I wanted to check out is the wire. I see the wire that is used wrap the armature on the custom motor is very fine and the size appears to be somewhere around 30-33 awg and the wire that is used on the armature for the XL motor appears even thinner. The custom motor can handle some power (up to 24 volts) but the motor required most of the load from 9v AA battery box to work well. However, two of these custom motors are to much for a single battery box to be powered effectively. The custom motor has two magnets with some gaps in between while the XL motor has one magnet that is completely surrounding the armature. One major difference between the two motors is the brushes.

[Boxerlego]

I have took a picture of the XL motor next to the modified XL motor to look at the length difference between the motors. I see that the modified motor is one module bigger than the XL motor. I have an Idea to remove the lift arms and use the cold weld to hold the motor on the inside of the case. But because the modified motor is one module bigger than the XL case, something must be done to the case that will allow the Motor to sit in place. I have a idea to cut/drill a hole in the back of the case big enough so the motor will stick out and some cold weld will lock the motor in place with the case. but if the motor breaks with this method, I will have no luck in replacing the motor that is cold welded in place. Currently the two lift-arms need to come off so the case can be fitted with the motor.

I have also been doing test with the geared up XL motor and it evaluating that aspect of the XL motor. I have notice that when using the servo along with powering two geared up XL Motors a fuse will trip in the V2 IR receiver. It can do a fast straight run for about 10 feet in 3-5 seconds before the fuse kicks in and slow it down and touching the servo make that slow down happen faster. I would not really recommend on using the internally "geared up" XL motor for driving. I have not tested the geared up XL motor with the air compressor yet.

Edited April 15, 2013 by Boxerlego

[Boxerlego]

I have completed the XL motor Upgrade. Every step was carefully done to keep the motor straight. My first step was to remove the lift arms from the Jb weld. My plan is to use the cold weld as a brace to center the motor in place against the case. I had to file down the cold weld on he motor until it was able to fit snugly in side the case. When that was done I went and drilled out a hole in the back of case to center the motor up. After centering the motor up with the case and double checking to make sure everything is straight and centered, I examined the case next to a light with the motor inside showing me where to make the hole for the motor to stick out. I used the same flat head screwdriver to open the XL motor to cut the lines in to the case. When the lines were cut in the case, I used a dremel to make the fitting hole in the back of the case. I used the straight sides of the motor to secure it in place with the hole on the case. The planetary gear box also help in centering the motor up with the case. I plan to make another motor. There was another interesting way I was going to secure the motor with the case and it was going to be with magnets from another motor.

[DLuders]

Interesting! Be careful about using JB Weld epoxy around electric motors -- it has magnetic properties and may affect the motor's performance. See this Eurobricks post for details. Perhaps a non-magnetic epoxy would work adequately, so as not to affect the motor's magnetic field.

[Boxerlego]

Yes JB does have a very little effect with the magnets in the motor. It is granulated steel after all, but I wonder what how much of a effect would these magnets have around the DC motor.... I have mange to do some simple test at the moment with the motor and added magnets. Running the motor without the added magnets appears and sounds faster then running the motor with the magnets. Turning the motor shaft with the added magnets around the motor feels stronger then turning the shaft without the magnets.

[Boxerlego]

I just increased the speed of the motor using magnets! I have a variety of neodymium magnets and I have been putting them on top and bottom of the motor seeing the effect that it has. I use the 5206 Lego speed computer to determine the speed of the motor. The normal speed of the motor is around 1500 rpm - 1560 rpm. The first set of magnets is a n35 10x2mm disc neo magnet and that was able to bump the speed up of the motor by 400 rpm producing a total of 1900 rpm. The second set of magnets is a lager and stronger neo magnet n50 20x4mm disc type and that was able to bump the speed up by 300 rpm but it also decreased the speed of the motor by 250 rpm from the normal speed. I was playing with the positions of the magnet on the motor and it was effecting the speed as well. Now the polarity of the magnets does matter here. I have the north and south poles marked on the motor. Posting the magnet to get this effect is a difficult because it seem like the magnet repel at the spot that produces the most rpm. The area that the magnet is wants to go to seems to be the area that bogs down the motor more. This is a very interesting effect that adding magnet to the motor can effect the speed of the motor.

Edit: This arrangement of magnets manage to increases the rpm of the motor by a maximum of 1000! I need to get that decoupling capacitor on the motor...I can show you the spark that occurs when you don't have one.

Edited April 17, 2013 by Boxerlego

[Boxerlego]

I've ran a series of test on the motor and the results are interesting. Both gear Ratio on the XL planetary gear box was tested in the process along with load and no load condition. I've manage to get the fully geared down XL planetary gear box going at whopping 800 RPM with the help of a series battery connection producing a total of 16 volts. Now I've also manage to put a multimeter up to the motor to measure the current the motor is using. The Neodymium magnets do make the motor run faster but at a higher current cost. The fully geared down original motor was able to run comfortably when lowering the 7.5lb 3.4kg load to the ground at 350-100mA now compare that to when you add the Neo magnets to the motor, the current goes past 2A when lowering the load to the ground. Any questions or thoughts concerns about this effect would be highly appreciated.

[DLuders]

@ Boxerlego: Hey, with that fast-running, modified Lego Power Functions XL motor, one may be able to achieve helicopter flight! Several questions:

1) How hot does the motor become when you run it for an extended period of time?

2) What is the cost of the Neodymium magnets, and do you The Lego Group ever adopting your idea to produce an "XXL" motor someday?

3) Did you modify the PF Battery Box to short-circuit its internal fuse?

[chorlton]

The magnets is an interesting idea. You might get better performance if you could arrange them in a cylinder shape, maybe around the inside of the plastic casing?

Apologies if I'm stating the obvious, but applying a current through the wires means they want to move perpendicular to the magnetic field, so you will get a stronger, more efficient effect at the top and bottom of the motor. At the sides (90degrees), the wire is moving parallel to the magnetic field and so there will be no effect, with various, decreasing effect between the two points.

Maybe some of those smaller neodymium magnets (http://www.amazon.co...m magnets cubes or http://www.amazon.co...odymium magnets could be placed around the inside of the casing to give a more regular, smoother magnetic field for the wires to move through? You'd want to ensure that your added magnets' field was aligned with the existing magnets inside the motor (no point in having N-N cancel out) so some trial and error would be required.

p.s. I heard a rumour that small neo magnets might be being withdrawn from sale in the US after some were eaten by a child so grab 'em quick of you're in the US.

Edited April 19, 2013 by chorlton