Platter Motor

[planckepoch]

Hi all,

can anyone recommend a good platter motor with controller? i'm looking to build my own lathe but with so many motors out there i thought i'd best ask some recommendations.

thanks

[planckepoch]

Forgot to add - for a direct drive system

[markrob]

Hi,

Direct drive will be tough to find off the shelf. You need a high pole count BLDC or AC synchronous motor to run well at the very low speeds required. Probably also need have a good quality external shaft encoder to get good velocity feedback as well. Let us know if you find one as a standard product off the shelf at a reasonable price.

Mark

[planckepoch]

thanks for the response mate - just done some more digging, i'm a newbie to this so it's taking a lot of research.

i've decided to go down the belt pulley route because it will be much cheaper. just discovered the maxon configurator so i've been working out rpm, gear ratio and pulley sizes to get a suitable torque and rpm that will be controllable with pwm - still mega expensive through that site! wished there was some other configurator out there with cheaper kit.

do you know the optimal torque needed to spin a 8-10kg platter?

[markrob]

Hi,

In the case of a platter with no cutter head load, the weight of the platter only affects the time to reach final speed for a given motor torque. This assumes the bearing you use is such that it presents little friction. This results in a nearly pure inertial load. You require torque to counter the force needed to drag the cutting stylus through the media you plan to use. The SL1200 is marginal for cutting at 1.5 Kg-cm. If you get up in the 10-15 Kg-cm range like the SP10, you should be good to go. You can calculate the time to accelerate a 10 Kg platter based on available torque give that Acceleration = Torque / Inertia. Do some Google searches and you will find some formulas to help you calculate the time.

Mark

[planckepoch]

thanks a lot for the helpful info!

on another note - i was looking at cross roller bearings with flange for mounting the platter - i would need to get a sub manufactured from the bearing to the platter, but if you have any valuable advice on bearing type that would be helpful.

[symatic]

I'd also appreciate some info on Bearings - mine are looking pretty dirty on a Presto 14B (similar to 8D). The ball bearings are dirty and theres lots of space between them, which doesnt look right to me but I'm not sure what they're supposed to look like!