DIY Coffee Grinder Drive

[ed_98]

Hello!

So I have a manual coffee grinder that I want to make a separate handheld coupling motor for (kind of like a hand drill but no varying speed or torque). Attached is a picture of what I have in mind. I can take care of the housing and coupling and the printing but where I'm not sure of is the electrical side of it. I measured everything and determined I need an 80 oz-in, 160rpm motor. I assume a dc gearmotor is a good choice? I was also thinking a momentary push button is the best choice for this. Can I just stick a motor that meets my requirements, wire it to a 9v battery and call it a day?

The sketch would be about 4in long and 1.5in diameter.

 

[rjenkinsgb]

That power (torque and speed) work out to about 10W at the output shaft; due to friction and inefficiencies, it will need rather more than that from the power source.

Probably near 2A at 9V.
The idea should work if your torque estimate is correct, but you will need a better, much larger, battery pack, something like a bank of NiMh rechargeables or some other high current capable cells.

A 9V battery can not provide high currents, I'd guess possibly 30 - 100mA before the voltage just collapses due to its internal resistance.

 

[Nigel Goodwin]

That power (torque and speed) work out to about 10W at the output shaft; due to friction and inefficiencies, it will need rather more than that from the power source.

Probably near 2A at 9V.
The idea should work if your torque estimate is correct, but you will need a better, much larger, battery pack, something like a bank of NiMh rechargeables or some other high current capable cells.

A 9V battery can not provide high currents, I'd guess possibly 30 - 100mA before the voltage just collapses due to its internal resistance.

I've never actually tested one, but I certainly wouldn't attempt to use one for something like this - it's far beyond it's capabilities.