- 6 -
remove the cause and take a measure to prevent its recurrence. If it is difficult to take a preventive measure or to prevent its
recurrence, consult with the machine tool builder or FANUC.
- Check the motor for any scar, crack, deformation, bulge, etc.
- If the interior of the motor is visible or there is interference with a
peripheral component, it is imperative to replace the motor or the
- A light peel-off or scar of the surface may be repairable; consult
Appearance of the
Wet or dirty part - If you find any wet or dirty part, clean it immediately.
- A preventive measure is needed if the part in question remains wet
continually due to cutting fluid or dew condensation.
Operating conditions Temperature,
- Comply with the operating conditions of the machine. For details of
the operating conditions of a specific motor, refer to the
corresponding DESCRIPTIONS manual. Generally, the ambient
temperature should be 0°C to 40°C (or 30°C for a spindle unit)
and dew condensation is not allowed. In a place subject to severe
vibration, the components of the motor may be broken.
Cable - Check for any cable sheath damage, exposed conductor, damaged
conduit or cable bearing, abnormal bending, loose terminal, etc.
- If there is any trace of fluid flowing, the fluid may have entered the
inside of the motor or connector. It is necessary to make a check
and take a measure to prevent recurrence.
Connector/terminal - Check for any cracked, exposed, loose, or removed terminal or
- Fluid causes a failure; be sure to remove fluid.
- A scarred or damaged connector or terminal needs to be replaced.
In the case of a resin molded motor, such as a linear motor, the
motor needs to be replaced.
Noise/vibration - Check for any abnormal noise or vibration not only when the motor
is running (the spindle is rotating) but also when it is stopped.
- Abnormal noise heard when the motor is rotating indicates an
abnormality of the bearing or a failure inside the motor.
Movement - Check that the motor operates normally and smoothly.
- If the circuit breaker trips at the same time the motor starts to
operate, it indicates abnormal motor windings.
Operation of the
Heat Check whether the motor does not overheat during the normal
Note: While the motor is running or immediately after it is stopped, the
motor surface may become very hot. Instead of touching the motor
directly by hand, use a thermolabel, surface thermometer, etc.
Winding resistance If the resistance value exceeds the specified range, the motor needs
to be replaced.
Note: When conducting winding resistance measurement, disconnect
the motor from the amplifier and measure the resistance at the power
line or connector closest to the motor.
characteristics of the
For the measuring method and judgment criteria, see the table that
(for a model with a
Noise/vibration - Check that the fan blows air normally without causing abnormal
noise or vibration.
- If abnormal noise is heard even when the motor is stopped, it
indicates a fan motor failure.