A blank display on the keypad is an indicator that there is no power being supplied to the keypad. There are a few reasons why this may be happening listed below. For the purpose of troubleshooting it is assumed that the unit is plugged into an operational receptacle and properly powered on at the disconnect switch the electrical box open. Only qualified personnel should open the electrical box on the grinder.
VFD has no display
If upon power up the VFD has no display, qualified personnel will need to meter the incoming voltage at terminals L1 and L2 of the VFD. If 208-220Vac is present, the VFD has failed and needs to be replaced. If there is no voltage metered, qualified personnel must then meter the L1 and L2 terminals at the bottom of the disconnect switch. If voltage is metered at this point, the EMC filter which is mounted below the VFD has failed and needs to be replaced.
VFD displays “JF”
A “JF” fault code indicates a loss of communication between the keypad and VFD. Qualified personnel will need to reattach disconnected wires between VFD and keypad. If all wiring is sound and still no keypad display, the keypad has failed and needs to be replaced.