Need help with a Yaskawa CPCR-QR servo drive

Hi guys,

We're testing out the spindle drive and we've run into a problem, the old Servopack CPCR-QR drive requires a speed reference and a run command. So I apply a few volts on terminals 1 & 2, and I close the circuit between 16 & 17.

The problem is that sometimes it runs, most times not. The drive is humming and not getting hot, sometimes the spindle is rocking back and forth, sometimes a little, sometimes a lot. No faults are being shown, and the resolver appears to be working.

When it does run, the speed is not always constant. You can hear the drive slow down and then pick back up, and as often as not the drive will then just die and the spindle will come to a stop.

Nothing on the drive has been touched, especially no pot-tweaking. The only thing different is that the drive is laid down (the control box is designed to allow the drive to be tilted out) from its normal vertical position, maybe an old relay doesn't like this?

So question #1 is: Has anyone ever seen this behavior before, and what did it require to fix it?

#2: If we decide to upgrade to a new servo drive, what would be a good choice?

#3 What about retrofitting the lathe with a 3 phase motor and VFD?

Thanks!,

John