how to power 12> PF motors? (big project)

[shadow_elenter]

Hello,

I'm new her so I'll intro myself a bit first.

I'm from holland, 27 years and a lego technic veteran. lego technic was my favorite toy  when I was a kid and I build endlessly... but never from the books. 
at some point I sold all my lego because I thought I was to old for it and I wanted a motorcycle, regretted that from the moment i did. So recently I bought 3 sets (bulldozer 8275, wheel loader 42030 and logging truck 9397) and the new bucket-wheel excavator is on the way because I already ran out of parts. enough about me;)

I'm currently working on a factory type build and i've used 7 PF motors so far and I"m far from done. currently running everything off 3 PF battery boxes but since I'm planning to buy at least 3 sbrick's and a bunch more PF motors( 5 probably to start with) i'd like an alternative power supply.

Almost all my projects will be stationary so a plug in the wall socket solution would be best for me.

Now I've seen the GBC guys use the old style train controller but... It's really hard to find anything on that subject!

like how many PF motors I can power with that?

Can anyone tell me what the options are to power this many(and growing) PF motors or where I can find this info?

PS: the build is quite interesting and I'll post it here when I have made a few pix ;) 
 

[Jeroen Ottens]

The best solution will depend on the amount of power that you need. The standard lego batteryboxes have 1A current limiter. You can try to power 4 motors from one batterybox, but your load must be small then otherwise this limiter will kick in.

For all the technical details on the lego PF system I would recommend to check out philo's homepage

[Kelkschiz]

It sounds to me like you just want to get some power adapters. You just have to find an adapter that transforms 220V DC to 9-11V AC, capable of providing 1-6A. The amperage depends on how heavy you are loading the Sbrick. Personally I would keep it below 3A.

When you found the right adapter you just have to connect the wires coming out of the adapter to half of a PF extension wire. Of course you will need make sure you are connecting it in the right way.

I think that is the cheapest and easiest way to provide your creation with cheap power.

Like Jeroen said, Philo has a lot of information about PF on his website, including how much amperage each type of motor draws.  

 

Edited November 25, 2016 by Kelkschiz

[letsbuild]

What I have is an old 9v train controller and it plugs directly into the wall. I use it for testing out systems, but I guess it could be used for your purposes, seeing as it's not a vehicle.

 

Cheers,

Let's Build

[dr_spock]

I believe the old 9V train speed controller uses a LM317 regulator.  I think it can do above 1.5A.  You're going to need more than one of them to drive 12+ motors. 

I use AC to 9V DC wall adapters to power my stationary MOCs.  I have a bunch of them from various old electronic equipment like modems, etc.  I adapted my PF battery boxes to use them.  I have lots of PF battery boxes and don't feel like cutting up good PF extension cables to make adapters.  The current limiter can be desoldered from the battery box circuit board if required.

 

[shadow_elenter]

Thank you for your reply's everyone! 

I think a 9V AC adapter wit a 3A output connected to a modified extension is the way to go for me.
I don't se any reason to use bulky train controllers since the speed regulation will be up to the Sbrick.

My electrical skills are minimal, but as I understand it I can only hook up a limited amount of motors to a 9v 3A AC power supply.

what is a good rule of thumb here ? 4 XL-motors,6 L-motors ,8 if there M-motors?

[zux]

Since you are new you probably don't know about Bricklink yet. Train regulators are pretty cheap and easy to get.

[shadow_elenter]

I know there cheap, but there just as expensive as an adapter so why would I want the bulky thing?

[Captainowie]

The question of "How many motors can I power from one <battery pack/train regulator>" isn't particularly easy to answer. Each device can provide a limited amount of current draw (typically about 1A), and each motor draws a different amount of current depending on how heavily it's loaded. From the figures here, you could run 10 XL motors from one battery box, as long as they weren't actually driving anything. Or, they could be working quite hard powering conveyor belts and whatnot, and you will only be able to have two of them on the same battery box.

As far as being able to draw from mains power, you have a couple of options, most of which have already been covered. Everything has so far been limited to one power point per battery box (or if you're modifying extension cables rather than battery boxes, one power point per SBrick). A while ago I converted an old PC power supply to be able to power three battery boxes from one power point. My writeup is here, and the Eurobricks discussion is here. I've since expanded that system so that I can power three battery boxes and 10 train controllers from two power points.

Hope that helps!

Owen.

Edited November 26, 2016 by Captainowie
More content

[Minique85]

On 11/26/2016 at 6:47 AM, dr_spock said:

I believe the old 9V train speed controller uses a LM317 regulator.  I think it can do above 1.5A.  You're going to need more than one of them to drive 12+ motors. 

I use AC to 9V DC wall adapters to power my stationary MOCs.  I have a bunch of them from various old electronic equipment like modems, etc.  I adapted my PF battery boxes to use them.  I have lots of PF battery boxes and don't feel like cutting up good PF extension cables to make adapters.  The current limiter can be desoldered from the battery box circuit board if required.

 

hi @dr_spock,

Do you have some pictures of the changes made to the battery box? I also have a bunch and would like to get away from batteries.

Thank you.

[shadow_elenter]

Thank you Captainowie, that is exactly what I mean! VERY helpfu info! It inspired the following idea:

I'll buy a power supply(possibly a computer one)

4 on/off switches

4 voltage regulators
4 amp limiters

4 AC voltage& amp meters 

4 PF connectors (from 2 cut up extension leads)

 

I'll split the supplied power into 4 leads each with it's voltage reduced to 9V and it's current limited to 3A then put in a AC volt&amp meter and then connect the PF connectors.

the Idea is that I can just click on a Sbricks & motors and when the amp peaks go near the 3A under full motor stress I'll know to start using the next output channel 

Is this a plan that could work or am I bound to run into problems here?

 

[dr_spock]

6 hours ago, Minique85 said:

hi @dr_spock,

Do you have some pictures of the changes made to the battery box? I also have a bunch and would like to get away from batteries.

Thank you.

Yes, there are pics in one of my old topics:  http://www.eurobricks.com/forum/index.php?/forums/topic/84269-mod-8881-pf-battery-box/

It is one way of doing it.  Plus I can reuse the battery box with batteries in an emergency by unscrewing the power jack.

[Captainowie]

18 hours ago, shadow_elenter said:

Thank you Captainowie, that is exactly what I mean! VERY helpfu info! It inspired the following idea:

I'll buy a power supply(possibly a computer one)

4 on/off switches

4 voltage regulators
4 amp limiters

4 AC voltage& amp meters 

4 PF connectors (from 2 cut up extension leads)

 

I'll split the supplied power into 4 leads each with it's voltage reduced to 9V and it's current limited to 3A then put in a AC volt&amp meter and then connect the PF connectors.

the Idea is that I can just click on a Sbricks & motors and when the amp peaks go near the 3A under full motor stress I'll know to start using the next output channel 

Is this a plan that could work or am I bound to run into problems here?

Well you certainly could do that, but it seems like a bit of overkill.

Why do you need voltage meters? If your regulators are putting out 9V, then 9V is what your voltmeter will say! You could probably do away with the ammeter too (depending on the behaviour of your amp limiter) - when it cuts out, you've got too much current draw!

You might find it easier to go directly into a battery box - that gives you a current limiter, as well as an on-off-reverse switch and power indicator for about the same price as a PF extension cable.

Either way, let us all know how you get on.

Owen.