How to select motors?? 24V Power supply.

Hi all,

I'm finally trying to choose suitable motors for my CNC project..

• I have a really superb 24V 40A Power Supply
• I have TB6560 AHQ driver IC's
• The machine is a 100 year old Drummond Round Bed lathe, but I am converting it to a 3 axis Mill, 12" between centers, 4" swing.
• Planning on using toothed pulleys and perhaps a 2:1 reduction to double the motor torque, at the detriment of speed

A friend used NEMA 23's on a small mill of similar proportions, but direct 1:1 drive, 24V supply, and the same driver IC's. May I get away with NEMA 17's?

Also when looking at the different NEMA frame sizes available, there are a few options within a set frame size.... hmmm...??

Been looking at: Motion Control Products as this is where my friend bought his from.

Any advice is well appreciated.. It's a big expense, so I want to get it right!!!

Thanks, Scott

Hi

I have a really superb 24V 40A Power Supply
I have TB6560 AHQ driver IC's
The machine is a 100 year old Drummond Round Bed lathe

By choosing the TB6560 you have limited yourself on the size of the motors you can use and the voltage of the PSU.
Having limited yourself, you need to use the most powerful motors you can within that spec, because the Drummond is a heavy old lump of cast iron..

Look at the max amperage output from the TB6560 and choose Nema 23s to suit, probably 3 to 3.3 Nm. but depends on the exact spec.
You may have to gear down these 3:1

It is a pity you have already bought the PSU and driver.
I would not recommend anything less than 48v PSU and in fact use a 76v PSU with Leadshine type drivers on both my stepper machines.
I don't think the TB6560 can take more than 36v, but it might be limited to 24v, after which it blows up!

Check the prices of Motion Control products against Zapp Automation prices.
Gary used to work for Motion Control and still sources a lot of stuff from there. Sometimes his prices are keener and through his Ebay shop often have free P&P.


regards

Hi, thanks for the suggestions so far!

This thread shows my Drummond RB : other thread

My PSU was gratis, so can't complain, just one limiting factor I have to work with.

I chose these driver IC's as they are what's used on the cheap chinese boards, and they did not break the bank!

My budget is almost non existent, so it's a bit of a make do and mend project.

Good to learn a little about which specs of the motors to be most interested in, so I guess is the highest voltage for the current that the IC can deliver..

I do have a really nice little torque wrench (branded by RS components, it resembles a fat screwdriver and has a 1/4 inch hex drive). I can attach this to the handle, and see what torque i am applying by hand to get it moving - it might point me in the right direction.

Thanks, Scott