Motors comparison page updated

[Philo]

My motors comparison page now includes tests of the E-motor from Renewable Energy Add-On Set (9688).

Enjoy!

Edited January 12, 2011 by Philo

[imajor]

I think there is a typo in the link, it didn't work for me.

[rien]

Works for me thnx philo for sharing youre knowlege!

[Philo]

I think there is a typo in the link, it didn't work for me.

Thanks, corrected now!

[freakwave]

Hello Philo,

Thanks for sharing this information, your page is always a welcome resource!

I was going through the PF-Section I was looking for some information on how much current/power the PF-IR recevier can control? Especially when reading your recommendation not to connect the 5292 to the RCX/NXT. But I could not find anything on the possibilities with it.

I guess (?) that the IR Receiver has some protection inside to prevent it from frying its internals one too much current.

Thanks

fW

[Philo]

I was going through the PF-Section I was looking for some information on how much current/power the PF-IR recevier can control?

Yes, something I should test and write up somewhere...

I guess (?) that the IR Receiver has some protection inside to prevent it from frying its internals one too much current.

Indeed. Il all depends on the LB1836M motor driver. If you look at datasheet, you'll see that the driver is rated 400mA per channel. But the real limitation is the incorporated thermal shutdown. So you may go above this figure on one channel if the other is more or less idle, or for a short time (published curves stop at 550mA so this is a reasonable limit). Anyway, it is really sturdy, and I have yet to see one fail!

[Tobbe Arnesson]

Thanks Philo! I often find myself on that page of yours! Great stuff!

information on how much current/power the PF-IR recevier can control?

I'm been there expecting to find the same thing, failing that I started this thread that quickly generated some great answers: http://www.eurobricks.com/forum/index.php?showtopic=49092

[Philo]

I'm been there expecting to find the same thing, failing that I started this thread that quickly generated some great answers: http://www.eurobricks.com/forum/index.php?showtopic=49092

Great to see you around, Tobbe Interesting thread indeed. Shows it would be useful to get more practical data!

[freakwave]

Thanks Philo! I often find myself on that page of yours! Great stuff!

I'm been there expecting to find the same thing, failing that I started this thread that quickly generated some great answers: http://www.eurobrick...showtopic=49092

Thansk for pointing me in the right direction! That's a good experimental thread!

I will try the high-power 5292 if there is a shutdown in the receiver and let you know in the other thread.

[MarcoB]

Great site you have there! It has been very useful many times

[CP5670]

Good to see you here on EB. Like many others, I've always found your motor page to be a great resource.

This E motor seems pretty lousy compared to the PF M though, except for its intended use as a generator. It's not as fast as I would think given the low torque. Although I do like faster motors in general since they put less stress on long geartrains and let you do the gear reduction yourself at the end.

[Toastie]

My motors comparison page now includes tests of the E-motor from Renewable Energy Add-On Set (9688).

Enjoy!

Thanks Philo!

Your motor comparison page is invaluable. I used it a thousand times I guess. So nice that you keep it updated.

Best regards,

Thorsten

[rgbrown]

Thanks for another addition to a great resource.

If you were interested in doing some more experiments (seeing as you look pretty well setup there!), one I'd be really interested to see is a characterisation of linear actuator efficiency under different loads. Especially comparing the difference between the new (8043) ones and the old ones.

I guess the experiment would go something like this:

1. Create a profile of torque vs. angular velocity for e.g. an M-motor (you already have this on your page), but it might need to be remeasured for the motor being used.
2. Configure a motor and linear actuator so that the linear actuator is lifting a constant mass (it would be interesting to compare the upward and downward performance too)
3. Measure the angular velocity of the motor. (or the speed of the actuator shaft)
4. From this angular velocity you can work out the input mechanical power (using the profile to estimate the torque on the motor), the output mechanical power, and hence the efficiency
5. Change the mass lifted by the actuator, and repeat

I want to do this experiment myself, but I don't currently have a bench power supply, or a particularly easy way to measure angular velocity.If you, or anyone else, feels like performing this experiment, I'd be pretty interested in seeing the results. If not, I'll eventually get around to doing it myself!

Edited January 12, 2011 by rgbrown

[Philo]

one I'd be really interested to see is a characterisation of linear actuator efficiency under different loads. Especially comparing the difference between the new (8043) ones and the old ones.

Problem is to measure what you want and not something else. It's rather easy to pull a weight, but pushing it up while keeping it balanced is not so easy (friction in external guiding). A lever would probably be the way to go... The other issue is that - as any indirect measurements - precision might be low.

[rgbrown]

Problem is to measure what you want and not something else. It's rather easy to pull a weight, but pushing it up while keeping it balanced is not so easy (friction in external guiding). A lever would probably be the way to go... The other issue is that - as any indirect measurements - precision might be low.

Rather than using a guiding, you can have a diamond shaped linkage to provide lateral support with minimal friction

   o
  /|\
 / | \ 
/  -  \
o  | |  o
\ | | /
 \| |/
  \-/
   o

But yes, you could not completely eliminate this. I would probably also set it up to lift a weight via a couple of pulley wheels.

But yes, I agree that this kind of test would be less precise than your motor tests. I do, however, I think the qualitative results would still be of interest - it could also help to provide guidelines on when it is advantageous to use two coupled LAs, etc.

OK, so I'll do some experiments soon

[Tobbe Arnesson]

Great to see you around, Tobbe

Thanks.

Crawling out from the rock where I was hiding was somewhat of a shock with relearning the community and all, your page was a firm familiar turf to start from.

[Hopey]

Still not sure if I'm supposed to bump old topics for small questions...

I noticed on this page, in the summary at the bottom, that

Minimotor 71427 is probably the best performer of the pack overall.

I'm a little confused by this; it appears to have slightly less torque, speed and efficiency than an M motor.

Is this just an outdated statement, or is there something to this motor that I'm not aware of? I have one of them (from a power puller), but hadn't really considered using it in MOCs as it seems easier in most cases to just use one of the many M motor's that I've got.

[750ACE]

Is there a difference between the 5292 motor and the motors on the comparison chart that shows RC motor 1 and RC motor 2. Are there different versions or part numbers?

[Kierna]

It has two output axle holes, different gearing. I think the outermost one is higher speed?

[Philo]

I'm a little confused by this; it appears to have slightly less torque, speed and efficiency than an M motor.

Is this just an outdated statement,

Indeed, this comment is somewhat outdated. M-motor is indeed more powerful. But 71427 leaves it in the dust for efficiency. 71427 also has interesting capabilities

- it can be easily back-driven (eg. for return to center applications)

- it can be used as a generator, even better for that than the E-motor.

- it's no-load current is extremely low, making it suitable for energy starved conditions, eg. solar panel experiments

It has two output axle holes, different gearing. I think the outermost one is higher speed?

Two holes indeed with different speeds. Outmost is the slower one, with more torque. Speed ratio compared with the other hole is 17/23.

[750ACE]

Ok so there is only one motor (5292) with two output ratings.

[750ACE]

Does anyone know the battery life of the rechargable LiPo Battery when using two 5292 motors? Is it really required to use two 5292 motors like in the original buggy sets?

[DLuders]

From Philo's webpage, there is this graph of the 5292 Lego RC Motor's performance. At the bottom of that webpage, he has additional curves for TWO coupled motors. He wrote that those coupled "...curves show performance of two parallelled motors on the same receiver output....5292 motor was omitted too since one PF receiver output barely provides enough juice for one motor...."

[Philo]

One more problem is that the LiPo battery has an internal current limiting resettable fuse (the same as in other battery packs). It limits current to 0.75 to 1A continuous, and trips in a few seconds at 1.5A. Since one 5292 motor can easily consume more that 2A...

[750ACE]

One more problem is that the LiPo battery has an internal current limiting resettable fuse (the same as in other battery packs). It limits current to 0.75 to 1A continuous, and trips in a few seconds at 1.5A. Since one 5292 motor can easily consume more that 2A...

I feel a bit deterred about spending the money on these motors. I want my mocs to perform faster but feel it may not happen.

Will I be wasting money if I power 1 moter with 1regular battery pack using standard 1.5v batteries and a v2 receiver? I assume my 2000mah AA eneloops running at 7.2v will not put out enough amps causing a trip.

I am sorry if my posts seem redundant in conjunction with another user posting another topic related to the 5292 motors at the same time. I did review your entire site and it is extremely informative. Either I lover looked something or the information went right over my head.

I just want more power and more speed, is that to much to ask from lego.