Pulverizer Build Diary

[RogueTwoRobots]

Also, the shafts on the motors look very short and no bigger than 3-4mm in diameter. Getting a timing pulley to fit on that securely will be extremely difficult. If you do manage to do it (say it's a 10-tooth pulley) you'd need a corresponding pulley with 210 teeth to bring the wheel rpm down to 1000rpm (random figure assumed for melty brain spinner). A 44-tooth pulley of 5mm pitch is usually about 75mm in diameter, so that's already larger than the 73mm wheels you plan on using. Suffice to say a pulley with five times the amount of teeth will be around the 375mm diameter mark, so your wheels would need to be ridiculously big to fit the pulleys in, and your robot would become very unstable and/or overweight as a result.

[Mega Masher]

So what do you suggest for a reduction system then
DBT had no reduction system and that worked pretty well

[Max]

The motor used in NBT had 50% more power and rotated at 6000rpm rather than 21000 (3.5 times less).
But you are using 2 motors where it only used one, if I was you I would use mod 1 steel gears, with a 10 tooth on each gear and a 60 tooth on the wheels giving a 6:1 ratio which should make it just about manageable with your design. A lower gear ratio like 6:1 will probably be faster than a high one like 3:1 as the motors are under much less load so can use their power, this will also make it accelerate faster so you can get to your max. speed faster.
From what I understand you don't need an H-bridge as the motors only need to rotate in one direction at full speed every time, so a simple solid state relay for each one (rated at 100A continuous from RS components) will work great and be very simple. Remeber KISS.
You have to make the body and tooth very strong, I'd make it circular using a bit of large diamter thick wall steel tube (5mm) with supports on the inside (like DBT), if you don't have the equipment to weld or cut material this thick I would get it made by someone like Mario having first made a simple wood/plastic model to check everything fits. The tooth will have to be hardox or tool steel so will need to be waterjet cut.
I'd contact the guys who made DBT and ask if you can use their code and use the exact same components as they did, if this is not possible you will have to write it yourself. You can always use their's to begin with then modify it or re-write it at a later date but it would help if you had their's as a starting point as you know it works.

[Mega Masher]

Btw, Merry Christmas everyone!!!!

[Mega Masher]

Thanks for that Max