Turning Archive 2007

VFD Controller-long

Don Orr
>I'm looking to the collective knowledge here which I know is expansive. I have a Jet 1642 EVS lathe with a Variable Frequency Drive controller. This lathe is sold as continuosly variable speed from 0-3200 RPM. My problem is my lathe will not run below 125 RPM. A good friend who works with these controllers on his job came over to see if he could figure it out. We found that the lower frequency limit was set at 5 Hz, instead of 1Hz which should allow the motor to run much slower. We were not able to adjust the parameters because the programs were locked and need a password to unlock. I called JET Tech Support and told them all this. They said 125RPM was as low as this lathe should run (even though marketed differently). I asked if we could adjust the parameters down to 1Hz to see if made any difference. He said we could but it might affect the long term operation of the motor. He did give me a password to unlock the programs though. Before we go messing with this, does it sound like something that would be harmful to the motor? Are there any cautions I need to be aware of? I know there are some electronic wizards that hopefully can shed some insight on this.

The lathe is not under warranty anymore and I have not had a single problem with it. I want to try spraying finish while the piece is turning slowly to reduce drips and runs. I know others do this and I think 125RPM might be too fast. (Although the guy I spoke with at JET said he sprays at his lowest speed of 500RPM.)

Thanks for any help,


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