
2. SPINDLE MOTOR
B-65165E/02 MOTOR MAINTENANCE MAINTENANCE
- 229 -
(2) Checking the insulation between the winding and frame
Use a megohmmeter to measure the insulation resistance on 500
VDC. From the measurement result, determine whether the
insulation is acceptable or not according to the following criteria:
• More than 100 MΩ: Acceptable
• 10 to 100 MΩ: Deterioration has started. Although there is no
performance problem, periodic check is required.
• 1 to 10 MΩ: Deterioration is in an advanced state. Special
care must be taken. Periodic check is required.
• Less than 1 MΩ: Unacceptable. Replace the motor.
CAUTION
1 Before measuring insulation resistance, disconnect
the connection to the spindle amplifier module. If
insulation resistance is measured with the spindle
amplifier module connected, the spindle amplifier
module may be damaged.
2 During the measurement of insulation resistance,
applying voltage to the motor for a long time may
further deteriorate the insulation of the motor.
Therefore, the measurement of insulation resistance
should be performed in a minimum amount of time
where possible.