Haas Vector Drive Troubleshooting Manual page 4

Servo Amplifier - Troubleshooting Guide
NGC machines equipped with
a 60A servo
amplifier Alarm 3.991 Z-AXIS
AMPLIFIER OVER
TEMPERATURE.
Alarm 991 AMPLIFIER OVER
TEMPERATURE.
Mechanical Blockage
Corrective Action:
Make sure the axis has a clear path of travel. Tools, part fixtures, or workpieces that are too large can crash into the
machine enclosure.
Look at the machine's alarm history. Overload alarms followed by over current alarms are a sign of a crash.
Look at the machine enclosure, spindle and tooling for damage. Damage to the tooling, fixtures and enclosure are signs of
a crash.
If there are no signs of a crash, inspect the ballscrew and linear guides. They must move or turn freely by hand.
Amplifier Short Circuit Inspection
Check the amplifier for a short. Power off the machine. Disconnect the cables for the axis servo motor at the amplifier
that generates the alarm.
Erroneous alarm
generated by electrical
noise.
The Maincon/Mocon axis Remove the encoder/drive cables from the Maincon/Mocon PCB axis
channel is defective, or channel. Inspect the connectors pins. Test the axis on a different
there is a broken pin on Maincon/Mocon channel, if the problem goes away there is a problem
the connector. with the axis channel.
Page 4 of 8 pages
• Install a ferrite filter P/N 64-1252 to the Z-axis motor power
cables [2].
• If the machine has the ferrite filter installed and the alarm
persist replace the 60A servo amplifier with (P/N 93-32-5552F
or later).
• If the machine already has the 60A servo amplifier (P/N
93-32-5552F or later), check the amplifier for a overheat
condition. Look at the servo fan for correct operation and the
cutting application before changing any parts.