Going Shopping

I now needed:

• A spindle motor (Automation Direct)
• X-axis servo (Dorna)
• Y-axis servo (Dorna)
• Servo controllers/amplifiers (Dorna)
• Spindle motor controller (Automation Direct)
• Spindle encoder (US Digital)
• Brains (LinuxCNC, mintbox computer, Mesa 7i92 and 7i76)

Here is what I settled on.

• Spindle motor from Automation Direct: 5 HP TEFC 3 phase 208/220VAC 1800 RPM with a max speed of 2700 RPM.

This seemed like a good choice to me because the original spindle motor was 7.5 hp and 3000 RPM. I'm not going to be turning really small stuff so spindle speed isn't a major concern. Also, I'm not going to be running this machine in a production shop where every second counts so I didn't see the need to have as much power as the original motor had. We'll see if this turns out to be a problem, but I doubt it. The 7.5 hp motor from Automation Direct, and the larger VFD to drive it would have cost me an extra few hundred so I settled on the 5 HP.

• Servos:

I found someone selling AC servos with servo drivers on eBay for a very reasonable price. They were also the right size and seemed to have plenty of torque so I jumped on the opportunity. I got all three sets of servo and driver for $800. Here are a few pictures of the servos. They had the same mount as the original servos and they looked to be about the right power/torque so I took a chance. Also, how can you beat a deal for 3 1.2kW 3000 RPM servos and drivers for under $1000?

For spindle control I bought a GS2 VFD that was sized for my motor from Automation Direct. Among other speed control inputs it takes a 0-10V input which was convenient because the breakout board I'm planning on using has a 0-10V spindle speed control output.​

As you might imagine this was a welcome first step. It certainly appeared that my lathe spindle bearings were ok.