Tormach PCNC 770 - Page 195

Chapter 10
195
UM10350_PCNC770_Manual_0916A
Troubleshooting
Axes Drive Subsystem Checklist
Table 4.2 (...continued)
One axis will not move or moves in only one direction; other axes operate properly
Possible Cause Probability Action to Identify Cause of Problem Discussion
A defective
motor or motor
connection
Low
Power off and remove the motor leads
from the axis drive; inspect motor.
Unplug power connector from
the board. Check motor for
signs of coolant contamination.
Measure resistance of windings. See
Table 4.3.
When making resistance
measurements on motors and
other devices with low resistance,
always take a tare reading on
the meter before doing the
resistance measurement on the
motor or device. Refer to Using
the Digital Multimeter for Electrical
Tests earlier in this chapter.
If the resistance is out of range, check
the wiring carefully. If the wiring is good
and the resistance readings are out of
range, the motor is defective.
Disconnect motor leads
from the wiring and measure
resistance at the motor. Also
check the wiring (which is now
disconnected) for shorts wire-
to-wire or wire-to-ground and
for wire breaks.
A blown fuse on
the DC bus board
Low
Monitor DC voltage from the DC bus
board. See Table 4.4.
A blown fuse usually is the result
of a defective drive. If you replace
a fuse and it immediately blows,
suspect a defective axis drive or
wiring to the drive.
Mechanical
problem
Low
Gibs too tight or too loose
Adjust using Gib Adjustment
procedure described in chapter
9, Maintenance. Too tight results
in too much friction in the ways.
Too loose can cause binding.
Oil not getting to ways and ball screw
Investigate oiling system for lack
of oil and/or plugged lines. Refer
to Service Bulletin SB0031.
Oil residue from long-term storage
Repeatedly pump oil and slowly
jog axis.
Debris on ball screw
Clean ball screw
Thermal trip on
a drive
Low
Look at the LEDs on the axis drivers. If
there is a red LED lit on the drive, then
it has tripped.
Cycle power to the mill, and
the trip should reset. If problem
persists, replace drive.
(connued on next page...)