12V motor

[Good old Lego builder]

I remember that indeed with the train controller you could let it run very slow., without al lot of gears, which was a good solution for be because i didnt have a clue about gears back then.

[1974]

^{Yes, but slow speed on high RPM DC motors means very little torque. To maintian the torque you need gears. Allthough if you use too many (that is too many gears, not too high reduction) you again end up with little torque due all the firction in LEGO parts}

Edit : Sorry 'bout the formatting, dunno what when wrong there??

Edited July 21, 2013 by 1974

[Good old Lego builder]

OK, gears, I'm really not good with that, haven't done much with them. Read Sariels guide, but still.....pfffff.

Am I correct that, if I have an small drive gear on an axel with a bigger gear, the bigger gear than drives another small gear on an other axel, with on that axel again a bigger gear.......that last gear runs slower? And does that mean that the end result is more torque?

[JTS]

OK, gears, I'm really not good with that, haven't done much with them. Read Sariels guide, but still.....pfffff.

Am I correct that, if I have an small drive gear on an axel with a bigger gear, the bigger gear than drives another small gear on an other axel, with on that axel again a bigger gear.......that last gear runs slower? And does that mean that the end result is more torque?

Yes that's right. When you gear down (small gear to larger gear) , the driven gear is always slower but more powerful.

When you gear up (large gear to smaller gear), the driven gear will be faster but with less torque.

[Good old Lego builder]

So recently I read this topic again, and downloaded an app for my phone. A stroboscope / rpm measurement thing. I tried it with my 12v motor. It measured around 7200 rpm. Is that even possible?

 

Edited August 4, 2019 by Good old Lego builder

[Appie]

The old 90's Technic motor has 4100 rpm at 9V according to Philo's testing. So maybe? Perhaps like the 90's motor it isn't downgeared internally like modern PF/Control+

[howitzer]

7200 rpm is really fast, you won't find many household appliances running anywhere near that speed. Most power drills for example are much slower, though for example Dremel multipurpose tool can get higher. Considering Lego gearing, you'll probably lose a lot of torque to friction if you're going to gear it down to any reasonable speeds, but still I guess it's worth a try.