Vfd replacement issues

[Leo Flynn]

Hey, I have followed the VFD replacement instructions posted here using the Lapond VFD on a 3520b that is 8yrs old. Everything seems to be working but there are a few issues I can't get sorted. When the dial on the lathe, potentiometer is turned all the way down lathe should be off but it spins at 16-18 rpm, both forward and reverse. Seems this might be programming issue or maybe potentiometer is bad. No idea why doing this.

Also set max speed to 3440rpm as per the directions but can only achieve 2800 rpm.

Any help greatly appreciated!
Thank you
Leo

 

[Richard Coers]

When a potentiometer is bad, nothing turns. But I can't help you with programming.

 

[Vitor Cruz]

Hi Leo. If your VFD is from Delta, have a look on the pages 4-53….
You will understand your questions.
To reprogram the VFD you need the keypad to “speak” with it.

 

[Dean Center]

The vfd translates hertz into speed. When you program, or when they set the value at the factory, you set the minimum and the maxium hertz, and therefore the speed. With that in mind, if you want to get a higher maximum speed, you need to program in a higher maximum hertz. You will have to look up which parameter that is for your VFD, as it is not the same for different brands.

For the minimum speed, you set the minimum hertz parameter to a lower number. When you do this, be aware that there is a school of thought that says it's harmful to set the hertz/speed all the way to zero. And, of course, another school of thought that says it's not a problem.

 

[Michael Brown]

Hey, I have followed the VFD replacement instructions posted here using the Lapond VFD on a 3520b that is 8yrs old. Everything seems to be working but there are a few issues I can't get sorted. When the dial on the lathe, potentiometer is turned all the way down lathe should be off but it spins at 16-18 rpm, both forward and reverse. Seems this might be programming issue or maybe potentiometer is bad. No idea why doing this.

Also set max speed to 3440rpm as per the directions but can only achieve 2800 rpm.

Any help greatly appreciated!
Thank you
Leo

The coincidence of the speeds is actually suspicious. It's possible that the VFD is calibrated for a 50hz power source which would imply the minimum frequency is higher relative to the input frequency. Considering the top speed of motors are 2800/3500 for 50/60hz respectively.

Unless the VFD signal is fully converted to DC before generating the output signal, it is still likely using the power input frequency to drive the clock of the circuit.

Also the potentiometer range may not match between the old and new.