YASKAWA GA500 Maintenance & Troubleshooting page 55

Code Name
oS Overspeed
Note:
• The drive detects this fault if the motor speed is more than the value set in F1-08 for longer than F1-09.
• Do a Fault Reset to clear the fault.
• If the drive detects this fault, it will operate the motor as specified by the Stopping Method set in F1-03 [Overspeed Detection Selection].
Code Name
ov Overvoltage
YASKAWA TOEPYAIGA5001A GA500 DRIVE MAINTENANCE & TROUBLESHOOTING
Causes
There is overshoot.
There is an incorrect number of PG pulses set in the
drive.
The oS detection level is set incorrectly.
If the drive detects the fault at start or in the low
speed range (10% or less) and n8-57 = 1 [HFI
Overlap Selection = Enabled] for PM Control
methods, the high frequency injection gain is too
high.
Causes
The deceleration time is too short and too much
regenerative energy is flowing back into the drive.
The acceleration time is too short.
The braking load is too large.
There are surge voltages in the input power supply.
The drive output cable or motor is shorted to ground
(the current short to ground is charging the main
circuit capacitor of the drive through the power
supply).
If the drive detects ov in these conditions, the speed
search-related parameters are incorrect:
• During speed search
• During momentary power loss recovery
• When the drive starts again automatically
• When you use an IE3 premium efficiency motor
The power supply voltage is too high.
The braking resistor or braking resistor unit wiring is
incorrect.
Electrical interference caused a drive malfunction.
The load inertia is set incorrectly.
The Short Circuit Braking function used in OLV/PM
control method.
Possible Solutions
• Decrease C5-01 [ASR Proportional Gain 1] and increase C5-02
[ASR Integral Time 1].
• Use H6-02 to H6-05 [Pulse Train Input Setting Parameters]to
adjust the pulse train gain.
Set H6-02 [Terminal RP Frequency Scaling] to the pulse train
frequency during 100% reference (maximum motor rotation speed).
Adjust F1-08 [Overspeed Detection Level] and F1-09 [Overspeed
Detection Delay Time].
• Set E5-xx [PM Motor Parameters] correctly or do Rotational
Auto-Tuning.
• Decrease the value of n8-41 [HFI P Gain] in 0.5 unit increments.
Note:
Set n8-41 > 0.0 for IPM motors.
Possible Solutions
• Increase the values set in C1-02, C1-04, C1-06, or C1-08
[Deceleration Times].
• Connect a dynamic braking option to the drive.
• Perform Deceleration Rate Tuning.
• Make sure that sudden drive acceleration does not cause the
fault.
• Increase the values set in C1-01, C1-03, C1-05, or C1-07
[Acceleration Times].
• Increase the value set in C2-02 [S-Curve Time @ End of Accel].
• Set L3-11 = 1 [Overvoltage Suppression Select = Enabled].
Connect a dynamic braking option to the drive.
Connect a DC link choke to the drive.
Note:
If you turn the phase advancing capacitors ON and OFF and use
thyristor converters in the same power supply system, there can
be surge voltages that irregularly increase the input voltage.
1. Examine the motor main circuit cable, terminals, and motor
terminal box, and then remove ground faults.
2. Re-energize the drive.
• Examine the settings for all speed search related parameters.
• Set b3-19 ≠ 0 [Speed Search Restart Attempts ≠ 0 times].
• Adjust b3-03 [Speed Search Deceleration Time].
• Do Stationary Auto-Tuning for Line-to-Line Resistance and then
set b3-24 = 1 [Speed Search Method Selection = Speed
Estimation].
• Use these values to adjust the parameters.
• b3-03 [Speed Search Deceleration Time] = default value × 2
• L2-03 [Minimum Baseblock Time] = default value × 2
• L2-04 [Powerloss V/f Recovery Ramp Time] = default value ×
2
Decrease the power supply voltage to match the drive rated voltage.
Correct wiring errors in the connection to the braking resistor or
braking resistor unit.
• Examine the control circuit lines, main circuit lines, and ground
wiring, and decrease the effects of electrical interference.
• Make sure that a magnetic contactor is not the source of the
electrical interference, then use a Surge Protective Device if
necessary.
• Examine the load inertia settings with KEB, overvoltage
suppression, or stall prevention during deceleration.
• Adjust L3-25 [Load Inertia Ratio] to match the qualities of the
machine.
Connect a braking resistor to the drive.
2.4 Fault
2
55