On Mon, 26 Jul 2021 at 23:55, Earl Weaver <[email protected]> wrote:
> I have a lathe spindle with 8 in. chuck that is run with a 5HP Reliance > DC Motor and Reliance DC Drive. What kind of DC motor is this? Is it a permanent-magnet servo motor? Typically DC motors perform better at lower speeds than an AC induction motor, so I don't think that swapping to a motor/VFD combination will help. If the motor is running closed-loop speed control from the tachometer then, as suggested, you should test whether full rated current is being applied when the lathe is cutting at the limit. I would expect a speed-controlled loop spindle to feel springy. As you move the chuck faster than commanded speed the drive will reduce the current to try to slow the spindle (maybe even reversing in to braking) Then as you wobble it back the other way it will take some time to wind up the other way. The only way to make the spindle feel "stiff" in your test would be to close the position loop with the encoder, but then how do you drive it as a spindle with a speed command? -- atp "A motorcycle is a bicycle with a pandemonium attachment and is designed for the especial use of mechanical geniuses, daredevils and lunatics." — George Fitch, Atlanta Constitution Newspaper, 1912 _______________________________________________ Emc-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-users
