Yaskawa YASNAC PC NC Maintenance Manual - Manual (Page 178)

The VS-626M5 PC NC Maintenance Manual
4-157
Motor does not rotate
at commanded speed. Speed reference signal error Check speed reference on operation status display
(U1-02).
Readjust master speed reference function.
Motor speed adjustment error Check motor speed on operation status display (U1-
01) and adjust the speed using control constant C1-
12.
Speed is controlled by P control. Check if PPI signal is input or not on operation status
display (U1-09).
Torque limiting Check whether external torque limit signals TLL or
TLH is input on operation status display (U1-09).
Control PC board fault Replace the control PC board.
Extended accel/decel
time Soft starter time setting error
(Set time is too long.) Check the setting of control constant C1-10.
Motor code selection error Check the setting of control constant C1-25 on the
setting list.
Torque limiting Check whether external torque limit signals TLL or
TLH is input on operation status display (U1-09).
Excess load on load machine Check load status on the load factor meter for loss
and inertia moment of the load machine.
Increase the capacity of inverter and motor.
Control PC board fault Replace the control PC board.
Heavy motor noise,
vibration Inverter output disconnection Check wiring between inverter and motor.
Grounding error of motor or inverter Check continuity of motor and inverter to see if they
are securely grounded.
Malfunction due to noise
(Poor encoder characteristics) Check that encoder signal lines are separated from
inverter output wiring or other power lines.
Check encoder cable specifications (whether the
cable is a twisted pair shielded wire).
Control constant setting error
(especially speed control propor-
tional gain) Check control constants on the setting list.
Motor installation error Check for loose mounting bolts.
Unbalanced motor Check if rotor is balanced.
Replace the motor.
Motor fault
(Motor bearing fault, rotor fault) Run a motor alone to check if noise and vibration are
within specifications.
Replace the motor.
Defective load machine coupling or
centering Confirm that coupling and centering are appropriate
according to the connection with load machine.
Insufficient strength of load machine Check the load machine for deformations or reso-
nance.
Loose foundation bolts Check for loose foundation bolts on load machine.
Control PC board fault Replace the control PC board.
Motor does not stop. Control signal does not operate. Check that operation signal (FWD or REV) is open on
operation status display (U1-09).
Control PC board fault Replace the control PC board.
Table 4.38: Motor Faults and Corrective Actions (Continued)
Fault Cause Corrective Action