12v Crocodile Mod - Update, it runs

[Andy Glascott]

Hi all, 

My croc arrived a couple of weeks ago and got built last week. I put one of the 12v Technic motors (image below) in it and improvised a working, albeit imperfect, power pickup for the 12v centre rail. When I apply power I can hear the motor is wanting to work, and when I lift the centre unit (I haven't attached the end units in tests yet) off the tracks and supply power directly to the motor, it works fine and the wheels turn. Put it on the tracks, with power directly from the 12v power supply and it won't move, so my guess is that the rather old motor just doesn't have the power to get this wonderful loco moving.... Any insights or suggestions would be welcome. 

Thanks,

Andy

[XG BC]

you could try if it has the power to move itself without your pickups attached as they add quite a bit of friction generaly. maybe you could post some images of your pickup solution here so i or others could take a look at it. you could also try adding another motor or hack a powerfunctions motor ( hack apart a extention wire and wire that up to your pickup. just be careful not to turn up your transformer all the way as i am not shure for how long the 9v powerfunctions motor will handle 12v.

XG BC

[Andy Glascott]

Even without the pickups in place and powering directly it wasn’t moving.... I’m away from my layout right now but the pickup is a 1x2 plate with 2 small holes drilled through it to hold wires brushing against the power rail. 

[XG BC]

then you need to try a hacked powerfunctions motor as they have a lot more torque ideally an xl motor but if you just dont turn up the transformer all the way unless you are using a custom pwm controll system it should not burn up the motor also i think although im not shure the powerfunctions motors can handle 12v permanently.

you could also buy:

https://www.bricklink.com/v2/search.page?q=12v pickup#T=A

as this would be a better/more stable power pickup

XG BC

Edited August 23, 2020 by XG BC

[Toastie]

I don't think this is an issue of picking up power/the power pickups.

As @XG BC mentioned, the torque of the 12V motor you are using may be the issue. All the ciurrent PF L/Pup L motors have some serious down-gearing plus they use up-to-date motor hardware.

I'd suggest to simply use a PF L motor and funnel the power from the pickups to the motor. You need to modify a PF cable (just post here for instructions). But other than that, there should be no issue, even when you apply full 12V to the PF L motor for not too long time.

All the best,
Thorsten 

[1963maniac]

That motor probably spins fast with low torque. Gearing it down would probably help a lot. That 12V motor is probably similar to the 2838 motor.

The old 2838 9V motor spins at 2050 rpm with very low torque. See https://www.philohome.com/motors/motorcomp-old.htm  or https://www.philohome.com/motors/motorcomp.htm

[dr_spock]

I think you'll have to gear down that 12V motor to get enough torque to move the locomotive.  Grab some Technic gears and make a transmission. 

[Andy Glascott]

Thank you both. @XG BC, I have that official pick up piece, unfortunately there’s no way I can see to incorporate it into the croc. @Toastie, I have a PF motor I can play around with, and I’m fairly sure I have seen enough tutorials on here for such adaptations to have a go. 

[Toastie]

7 minutes ago, Andy Glascott said:

to have a go.

Do it!!!

All the best,
Thorsten

[Andy Glascott]

I'll keep ye posted, going to try the less destructive gearing options first and will update in a few days. 

 

[LEGO Train 12 Volts]

I hope to see the final result...

[Andy Glascott]

An update, as promised. The good news - a medium PF motor seems to have plenty of torque for the job. I was able to connect it directly to the 12v power pack via a combination of 9v - PF extension cable and an old 9v wire I've hacked by replacing one of the 2x2 plates with a 12v plug. All good so far. 

I then cut off the pf plug from the motor ready to hack onto my improvised pickups (which still need a bit of work to be more reliable) and found Philo's work describing the workings of pf - https://www.philohome.com/pf/pf.htm. By my reading of it I needed to strip the outer two wires from the pf cable and connect them to the power source, but when I did that nothing moved.... Am I connecting the right two wires to my 12v power source? 

 

[dr_spock]

The PF motor is wired to the two middle wires of the cable.  C1/C2.

 

 

[Andy Glascott]

14 minutes ago, dr_spock said:

The PF motor is wired to the two middle wires of the cable.  C1/C2.

 

 

Thank you, will try that tomorrow. 

[Andy Glascott]

It works! Here's a shaky, handheld phone video of it moving under it's own, ahem, steam.... 

The track is still quite dirty, a regular 12v motor was stuttering on it as well, but I'm delighted it works. I'm working on a new layout at the moment, this was a bit of a detour. Once the layout is up and running I'll work to get it a bit more reliable (clean the track for starters...). As it is, with only one set of pickups it won't go over the crossing track on this loop. Speaking of the pickups, here's a pic of what I used:

CrocWires by andyglascott, on Flickr

I drilled two small holes through a 1x2 plate and threaded two quite stiff wires through it. One end is twisted into a loop so I could connect the PF motor's wires to the set-up and the other is bent to connect with the 12v power rails. I can take more photos if folks would be interested in more. 

Edited August 29, 2020 by Andy Glascott

[XG BC]

great! looks really good. i am excited to see how the croc will run on the full layout! its also really stupid (atleast in my opinion that the pf motors have 4 wires goinb to them it only makes for a stiffer larger cable and more cost for the cable.) 

XG BC

Edited August 29, 2020 by XG BC

[Toastie]

Wow, nice!!!

This will definitely work. As you are not afraid of drilling through LEGO bricks: I can imagine power pickups from other brands, e.g. Carrera or the like (do they still exist?) mounted (mini-screws, glue, ...) to a plate/brick + soldering to the wires and so on and so forth.

I bet you'll succeed!

Very nice. Really very nice.

All the best and good luck!
Thorsten

[LEGO Train 12 Volts]

Finally here she is!

Great work!