Yaskawa YASNAC PC NC Maintenance Manual - Manual (Page 97)

PC NC Maintenance Manual Chapter 4: Troubleshooting
4-76
The motor noise is loud and the vibration is significant.
Cause and measures
The motor does not stop.
Cause and measures
Cause Measures
Main circuit disconnection Check wiring between the inverter and the motor.
The motor / the inverter earth is
defective Check that the motor and inverter are properly grounded and
check continuity.
Improper drive by noise (encoder
cable characteristic defect) Check the encoder signal conductor is isolated from the main
circuit wiring and other power lines.
Check encoder cable specification (twisted-pair shield wire)
[recommended cable “KQVV-SW” by Fujikura-Densen Co.]
Control parameter setting defect
Especially, speed control propor-
tional control gain Refer to the setting list for the control parameter.
Motor installation is defective. Check and tighten if loose, all installation screws.
Unbalanced motor Check the balance of the rotor.
Exchange the motor with a non-defective one.
Motor fault
Motor bearing error
Rotor fault Check whether the motor noise and the vibration enter the
specification value with driving with the motor unit.
Exchange the motor with a non-defective one.
Coupling / alignment with load
machine is defective. Confirm that there is enough coupling and centering according
to the connection with the machine.
Strength shortage of load machine Check that there are no transformation nor a resonating point
on the machine side.
Loosening of foundation bolt Check and tighten if loose, all foundation bolts on the load
machine.
Control card fault Exchange unit (exchange control card)
Cause Measures
Control signal does not operate. Check that the drive signal (FWD or REV) is set to OPEN by the
drive state display (U1-09).
Control card fault Exchange unit (exchange control card)