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Section 1
General Information
5-12 Troubleshooting MN722
Table 5-4 Inverter Section Troubleshooting Continued
INDICATION POSSIBLE CAUSE CORRECTIVE ACTION
New Base ID Software parameters are not
initialized on newly installed
control board.
Press “RESET” key on keypad to clear the fault condition. Reset
parameter values to factory settings. Access diagnostics and compare
power base ID number to list in Table 5-5 to ensure a match. Re-enter the
Parameter Block Values you recorded in the User Settings at the end of
this manual. Autotune the control.
No EXB Installed Incorrect programmed parameter. Change the Level 1 Input block, Command Select parameter and the Level
2 Process Control block, Process Feedback and Setpoint Source
parameters to a value that does not require an expansion board.
Need expansion board. Install the correct expansion board for selected operating mode.
Over Current FLT Current Limit parameter set lower
than drive rating.
Increase the Level 2 Output Limits block, PK Current Limit parameter.
Do not exceed drive rating.
ACCEL/DECEL time too short. Increase the Level 1 ACCEL/DECEL Rate block ACCEL/DEC parameters.
Encoder coupling slipping, broken
or misaligned.
Correct or replace encoder to motor coupling.
Encoder bearing failure. Replace encoder.
Excessive noise on encoder lines. Check the position counter in the Diagnostic Information for
jittering which will confirm an encoder problem.
Check encoder connections.
Separate encoder leads from power wiring.
Use Baldor encoder cable.
Cross encoder wires and power leads at 90°.
Electrically isolate encoder from motor.
Install optional Isolated Encoder Feedback expansion board.
Electrical noise from external DC
coils.
Install reverse biased diodes across all external DC relay coils as shown in
the Opto Output circuit examples of this manual. See Electrical Noise
Considerations in Section 5 of this manual.
Electrical noise from external AC
coils.
Install RC snubbers on all external AC coils. See Electrical Noise
Considerations in Section 5 of this manual.
Excessive load. Reduce the motor load.
Verify proper sizing of control and motor.
Overload - 3 Sec
FLT
Peak output current exceeded 3
second rating.
Check the Level 2 Output Limits block PK Current Limit parameter.
Change the Level 2 Protection block Overload parameter from Trip to
Foldback.
Check motor for overloading.
Increase Level 1 ACCEL/DECEL Rate block ACCEL/DEC parameters.
Reduce motor load.
Verify proper sizing of control and motor.
Encoder coupling slipping, broken
or misaligned.
Correct or replace encoder to motor coupling.
Encoder bearing failure. Replace encoder.
Overload - 1 Min
FLT
Peak output current exceeded 1
minute rating.
Verify proper motor data has been entered.
Check the Level 2 Output Limits block PK Current Limit parameter.
Change the Level 2 Protection block Overload parameter from Trip to
Foldback.
Check motor for overloading.
Increase Level 1 ACCEL/DECEL Rate block ACCEL/DEC parameters.
Reduce motor load.
Verify proper sizing of control and motor.
Encoder coupling slipping, broken
or misaligned.
Correct or replace encoder to motor coupling.
Encoder bearing failure. Replace encoder.
Over Speed Motor exceeded 110% of MAX
Speed parameter value.
Check the Level 2 Output Limits block Max Output Speed.
Increase the Level 1 Vector Control block Speed PROP Gain.
Continued on next page.