I bought a 101 year old mini-lathe (Drummond B type) and from what I've seen and read online it should be possibe to bring this lathe into the 21 century.
In my most extreme vision I would like to direct drive the main spindle and later direct drive the less torquey lead screw so I then would have 2 independent systems. This should later give me the option of precisely controlling the speed so could I could cut any pitch of thread by setting the speeds accordingly before I engage the half nut. If you are still with me, most VFDs have external control options so by using a Rasberry Pi, pre-determined parameters could be implemented by a push of a button (or will write a program taking user input and outputting correct speeds.)
My electrical knowledge is not excellent but I'm learning. In my setup I would like -
- Constant torque
- Varying speed between 50 - 2500 rpm.
- I’m in the UK so VFD input voltage is 240v 60Hz single phase.
There are also other factors in play such as -
- Start up torque (should be 1.5 times running torque)
- Power factor
I would like to know what torque range can I achieve on single phase VFD as I would like / need about 200 - 300 Nm at low RPMs (300 - 400 at start up) (this occurs normally in traditional motor systems (low RPM = more torque) but the VFD const torque is just confusing me now.)