Tormach 8L - Page 74

7: TROUBLESHOOTING
©Tormach® 2021
Specifications subject to change without notice.
Page 74 UM10753: 8L Operator's Manual (Version 0321B)
For the most recent version, see tormach.com/support
Cause: There's no power to the VFD because contactor K2 is not energizing. (Examine the voltage across 112/N and 117 at the VFD,
which should be 115 Vac nominal.)
Probability How-To Steps
High There are loose power or control wires in the VFD circuit.
1. Power off the machine (see "Power Off the Machine" (page35)).
2. Examine the circuit for loose wires.
3. Power on the machine (see "Power On the Machine" (page33)) and test operation.
Probability How-To Steps
Medium
1. Examine the spindle cover door to verify that it's being held closed.
2. Verify that there's 24 Vdc measured from wire 400 to wire 436.
Probability How-To Steps
Low Thermal switch (TS1) tripped, preventing K2 from latching.
1. Power off the machine (see "Power Off the Machine" (page35)).
2. Allow the brake resistor to cool, and reset thermal switch by pressing reset button (between its two terminals).
Probability How-To Steps
Low The control board isn't providing a run command or holding the K2 contactor on.
1. Examine wires 434 and 436 for 24 Vdc on wires J10.1 and J10.3, respectively.
2. Start the spindle and listen for a soft, audible click on the control board. If you hear this click (from a relay contact on
the board), the machine control board is functioning properly. If you don't hear the click:
l Verify that there's 24 Vdc measured from wire 400 to wire 434. Make a jumper wire and, carefully,
momentarily jumper wires 434 and 436.
o
If contactor K2 pulls in (you will hear an audible clunk) while you have the jumper on but drops out as soon
as you remove the jumper, the holding contact on K2 is defective.
o
If K2 stays powered on, the control board is not passing the run signal to the circuit. The control board
passes 24 Vdc from wire 434 to 436 via a relay to create the start pulse. Measure wire 434 for 24 Vdc
power. If present, the control board or wire 436 connected to J10.3 is defective. Power off the machine (see
"Power Off the Machine" (page35)), and jumper J10.1 to J10.3 Power on the machine (see "Power On the
Machine" (page33)) and check the VFD for a display. If the VFD reads rdy, the control board is defective. If
not, wire 436 may be broken. Lift the connections of wire 436 at the control board and K2 and measure
continuity.