8-8. IC destruction by relay noise of inspection machine
A mechanical relay for On-off control of electric connection between IC and
inspection machine was used. Surge was generated when it was on-off, and it was
put into IC.
The motor doesn't rotate by the over voltage destruction of IC.
Use the wet relay (mercury relay etc.). Confirm surge is not generated when the relay
Fig. 8-7 Example to surge waveform when mechanical relay is used
8-9. Motor failure (missing phase output)
The motor has missing phase output that was shipped to the set maker.
The motor might start depend on the position of the rotor when starting even if the
motor has missing phase output. Therefore, the missing phase output of motor
cannot be detected by the motor rotation test.
Monitor the Motor current or the torque pulsation in order to detect the missing phase
output of motor.
missing phase output
Fig. 8-8 Example to Motor current waveform of the motor that has missing phase output