39 - PVD 3661 MGV_ commisionning manual_March 2012.docx
4.5. Troubleshooting
We provide hereunder a symptom list in regard with their possible cause. This is not an exhaustive list so in
case of trouble, please refer to the associated servo drive manual (the diagnostic board indications will help you
investigating).
You note that the motor
does not turn by hand when
the motor is not connected
to the drive.
•
Check if the phases are not in short circuit.
•
Check if the rotor is externally blocked mechanically in rotation.
You have difficulty starting
the motor or making it run
•
If there is a thermal protector, check it and its connection and how it
is set in the drive.
•
Check the servomotor insulation (in doubt, measure when the motor
is hot and cold.
The minimum insulation resistance measured under 50VDC max is 50
M
Ω :
-
Between phase wire and housing,
-
Between thermal protector and housing,
-
Between resolver winding and housing.
You find that the motor
speed is drifting
•
Adjust the servo amplifier offset.
You notice that the motor is
racing
•
Check the speed set-point of the servo drive.
•
Check you are well and truly in speed regulation (and not in torque
regulation).
•
Check the encoder setting
You notice vibrations
•
Check the encoder and tachometer connections, the earth
connections (carefully) and the earthing of the earth wire, the setting
of the servo drive speed loop, tachometer screening and filtering.
•
Check the stability of the secondary voltages.
•
Check the rigidity of the frame and motor support.
•
Check motor fixing on its base.
•
Check the balancing.
•
Check the alignment between motor and load.
You think the motor is
becoming unusually hot
•
It may be overloaded or the rotation speed is too low : check the
current and the operating cycle of the torque motor
•
Friction in the machine may be too high :
- Test the motor current with and without a load.
- Check the motor does not have thermal insulation.
•
Check the cooling circuit
You find that the motor is
too noisy
Several possible explanations :
-
Unsatisfactory mechanical balancing,
-
Defective coupling,
-
Loosening of several pieces,
-
Poor adjustment of the servo amplifier of the position loop:
check rotation with the loop open.
-
Low drive switching frequency.
The motor is warmer on its
top
Air bubbles can be stocked in the water cooling circuit. You need to purge
the circuit or to double the water flow rate during 10 minutes to remove
the air bubbles.
