B-65285EN/03 MOTOR MAINTENANCE 2.SPINDLE MOTOR MAINTENANCE
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(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.