Saturday, December 13, 2008

TBs TechPoll 07 - PF u/S-Motor, which size?

Today, a poll set dedicated to hear what do you wish, for a smaller Power Functions motor.

As you know, when Power Functions was released in 2007, there were introduced two new motors. One medium sized (M-Motor) and another large size (XL-Motor).
Since then, builders have been waiting for their natural companion, a small or minimotor (S-Motor) and/or a micromotor (u-Motor).

Such hypothetical motor, probably wouldn’t be very strong, but small enough for applications where size is really important or very limited. It should be also useful for both TECHNIC and System constructions, as it happened with its predecessor.
We can’t be sure, but probably it never seen the daylight yet, due to issues related with reliable suppliers, production costs, LEGO Designers not having found significant usage for it, etc. However, hope should be the last one to die…

Also as many of you should have realized, since the new studless emphasis, TECHNIC system is primarily odd sized. This would be in favor of also odd sized motors, when we think of studless TECHNIC constructions and structures made of TECHNIC Beams, instead of TECHNIC Bricks.

Actual ‘M’ and ‘XL’ motors, measure respectively 3x3x6 and 5x5x6 studs.
Both have pin holes in front for fixation. The ‘XL’ motor has also two pin holes at each side for fixation, while the ‘M’ got a 2x6 plate like tube bottom for extra fixation.

So, actually the most obvious questions are:
  • Which size should an ‘u/S-Motor’ be?
  • Which form factor should an ‘u/S-Motor’ have?
  • Which type of fixation should/could an ‘u/S-Motor’ have?
  • Should it have high or low rotation speeds (geared or not geared down)?
  • Should it have high or low torque?

At least in what concerns the size, I see two main options for a Small size motor:

1) A thin and long version (similar to the ‘M’ version, but more compact)
This way, it would only make sense if being smaller than ‘M’, which would immediately force it to have a 2L diameter. Length could be as long as ‘M’ with 6L or shorter.
A 2L diameter form factor would prevent the presence of front pin holes for fixation and would limit the possibilities to fix it with pins.
The alternatives are: axle hole at the end; ½ or ¾ TECHNIC pin holes at the rear, in each side; one or two pin-holes in the back side (the option for one would be too less, and for two would be too unnatural. All these options would make the motor 1L longer).
A forth alternative would be the use of both studs on top and tubes at bottom, making it somehow similar to the old red micromotor and more suited to be used in SYSTEM constructions.

2) A wide and short version. This could go from a 3x3xN to a 5x5xN form factor, where N must definitely be shorter than 6. Something between 2 and 3, but also depending on the fixation design to be chosen.

Taking all these considerations, lets run a few polls to determine which would be your preferences regarding such hypothetical motors, LEGO may one day release.

The categories and options, are:

PF u/S-Motor, which size?
  • 2x2x6 motor
  • 2x2x4 motor
  • 2x2x3 motor
  • 2x2x2 motor
  • 3x3xN motor (2<=N<=4)
  • 5x5xN motor (2<=N<=4)

PF u/S-Motor, which fixation type?

  • Preferred pin/axle hole fixation
  • Preferred tubes/studs fixation

PF u/S-Motor, which torque?

  • Low torque motor
  • High torque motor

PF u/S-Motor, which speed?
  • Low speed motor (<100>
  • High speed motor (>100 RPMs)

Leave also your thoughts, into comments section from this post.


Captainowie said...

Surely some consideration should also be given to a motor of a size in between the two that we have already (i.e. of size L).
If there were no plans for such a motor, then I would have thought that the naming scheme would be either Large and Extra Large, or Medium and Large. I believe calling the motors Medium and Extra Large implies that there will be, at some point in the future, a Large motor, probably 4x4x6 or similar.

Conchas said...


Or maybe a 5x5x3 or similar, as an L-Motor, for instance

Anonymous said...

I would say that they would be 3 or 5 or 7,x 3 or 5, x 3 or 5.
Anyway, 1 would be kind of hard to put a motor in or gears and if there was, it would be way too fast or weak to do anything.

Lego Adam (Cagri) said...

I'd like to have a 3x3x3 motor with low torque, low speed. It would be great if they had pin holes on two sides. I rarely use the plate under the M motor.

BTW is it possible to have low torque and low speed at the same time? Gearing down creates a little torque?

Conchas said...

The problem with side pin or axle holes, is that they would directly reduce by appox. 2L the inner space available for the motor itself (specially for narrower motors like 3 or 2L).
So, the casing should increase to accommodate the holes. This is why I believe a really small or micromotor would have tubes/studs instead.

Yes, as you gear it down, you increase the torque, but in the end its all a matter to the original torque for the electrical motor chosen to produce such PF motor.
Low power motors don't have much torque. So it all depends on how much you gear them down.

Anonymous said...

I would really really like a large motor That has a very high speed (at least 1500rpm) and has a surprising amount of tourque, like the RC buggy motor in a PF style housing. The extra large motors are ok but I like to do the gearing down myself to suit the application. Besides where's the fun in only having to stick a wheel to the motor with only a tiny bit of gearing down. Plus to have in built gearing down only to have to gear it up again for certain applications (eg pneumatic motor pump) is pointless and VERY inefficient.

A small motor would be good but as they are only really needed when space is tight then I guess it would be most useful in this case to have a very slow output speed with a bit of tourque.

PS are the letters in the word verification random, as mine was quite rude which I found hilarious LOL.

solic said...

What about a small 2x2x3 or even 2x2x2 motor with no pinholes and no studs/antistuds, but fixation similar to linear actuator and compatibile with mount hinges dedicated to LA?

Conchas said...

That would be neat, but it would require also 1L just for the fixing structure.
Hardly usable for motor internals, unless it is used a clutch like shaft, as in the LEGO red micromotor (which I personally dislike to some extent).
In the end motor size would also increase.

Also it would be incompatible with LAs themselves.
Better if it would be in the opposite way. S-Motor form factor ends like the LA adapter blocks as I think to have also suggested in some previous post about this subject, here at TBs.
Should had added it, to the fixation pool, but didn't remembered. Now it's a bit late...

Ronald said...

Somehow I think this small/mini/micromotor was or is intended to be a high-torque, low speed 2 x 2 type motor with axle drive in the center. The pinholes can actually be half deep on the sides, to meet up with a half beam. Something like this will mesh perfectly with the new linear actuators and their brackets and would prevent the use of weak universal joints or difficult axle/gear chains.

Conchas said...

That's aligned to what I've suggested in the post, where 1/2 or 3/4 pin holes could be used to connect with the TECHNIC pins, of correspondent lenght.

That way, assembly could go together with half beams, but not necessarily.

AVCampos said...

I believe the current micromotor is fine, provided it gets a new casing and a PF connector.

Since the motor itself has less than 2 studs in diameter, a 3 studs casing diameter would be possible. This would allow for a half-stud thickness on each side, where pins 3/4 could be inserted for studless constructions, like the RCX does.

Sure, the micromotor is slow, weak and inefficient, but it is small and light, and the proof that it is useful is that many people still use it, even though "better" 9V motors exist!

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