Powermatic 3520b wont run

[Peter D'Attomo]

Went to start it up yestreday and it wont run. I unplugged & replugged, no change.
I reset the VFD, & disingaged the on off button( mushroom), unplugged it, heard 2 clicks from the VFD. Replugged it, initiated the on off & speed control, and the lathe ran.

I then lowerd the speed control & disingaged the off button; reingaged the on button and the speed control, but did not run.

Again reset the VFD, etc. turned down the speed control, but left the on off buttom on, works.
I suspect the on off button, but would appreciate any further info.
Thank you

 

[Joe Kaufman]

With the e-stop button in, look at the inverter display. If it displays a F and some digits turn the speed control pot and see if the display changes numbers. That is the speed reference input from the speed potentiometer and it is working. I believe the F is the default setting. There are other prefix letters to display other inputs and outputs. The next suspect is the e-stop button. You could put a jumper across the terminals connections to see if that corrected the problem. Safety wise, don't operate/use the lathe with the jumper in place.

The next thing to do is check the tightness of all wire terminal connections. A good thing to do every 2-3 years anyway. Be sure the machine is disconnected from the power source.

 

[Peter D'Attomo]

VFD dispalys F and 0.0.. Engaging the spped control the "tach" does dispay revolutions. Will try thge jumpers next.
Thank you very much.

 

[Dave Landers]

Might not be your problem, but I have had trouble with the start/stop button on my 3520B (and had similar trouble with my Jet 1642 with the same style of button). Sometimes it just won't turn on... I have to pull and push a few times to get it to turn on.

That big red button moves a tiny sliver of plastic that engages a microswitch. On mine, that plastic sliver gets stuck and doesn't move. Doesn't take much sawdust to stick it. If you take the control panel off the lathe, you can see it and make sure it is actually moving the microswitch.

When mine stops working, I blow out any dust and squirt in some dry lube (graphite) which seems to help.

 

[Joe Kaufman]

If the inverter F display does not go from 0 (minimum speed setting) to around 130 (max setting) smoothly, then you are not getting the speed reference to the inverter. The inverter will not operate w/o the input even if the e-stop is working and in the run position. The speed display on the front of the headstock is a completely separate device and should display something anytime the power is on and the spindle is rotated above a minimum speed threshold for the device. The speed reference is easy to check and a common problem. That's why I suggested to do it first.

The F display is the frequency input signal (Hz or cycles per second) that the inverter uses to match output frequency to the motor.

 

[Peter D'Attomo]

Thank you all for your ideas. It seems that by cheking all the connections and cleaning out the on-off button, the problem is resolved.Happy turning!

 

[Dean Center]

Like Dave, I too have had issues with the on-off button. When it gets fritzy, make sure the connections are tight, blow it off and make sure the button is snugged up properly to the headstock housing. This has worked for me.