6.10 Troubleshooting without Fault Display
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YASKAWA ELECTRIC SIEP C710616 30B YASKAWA AC Drive T1000A Technical Manual
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Motor Rotates After the Drive Output is Shut Off (Motor Rotates During DC Injection
Braking)
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Output Frequency is not as High as Frequency Reference
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Buzzing Sound from Motor at 2 kHz
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Unstable Motor Speed when Using PM
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Motor Does Not Restart after Power Loss
Cause
Possible Solutions
DC Injection Braking is set too low and the drive cannot decelerate
properly.
• Adjust the DC Injection braking settings.
• Increase the current level for DC Injection Braking (b2-02).
• Increase the DC Injection Braking time at stop (b2-04).
The stopping method is set so that the drive coasts to stop.
Set b1-03 (Stopping Method Selection) to 0 or 2.
Cause
Possible Solutions
Upper limit for the frequency reference has been exceeded.
• Set the maximum output frequency and the upper limit for the frequency reference to more appropriate values (E1-
04, d2-01).
• The following calculation yields the upper value for the output frequency = E1-04 x d2-01 / 100
Large load triggered Stall Prevention function during acceleration.
• Reduce the load.
• Adjust the Stall Prevention level during acceleration (L3-02).
Cause
Possible Solutions
Exceeded 110% of the rated output current of the drive while
operating at low speeds.
• If the output current rises too high at low speeds, the carrier frequency is automatically reduced and causes a whining
or buzzing sound.
• If the sound is coming from the motor, disable carrier frequency derating (L8-38 = 0).
• Disabling the automatic carrier frequency derating increases the chances of an overload fault (oL2). Switch to a larger
capacity motor if oL2 faults occur too frequently.
Cause
Possible Solutions
The motor code for the PM motor (E5-01 or T2-02) is set
incorrectly (Yaskawa motors only).
Motor Performance Fine-Tuning on page 268
for details.
Drive is attempting to operate the motor beyond the speed control
range listed in the specifications.
Check the speed control range and adjust the speed accordingly.
Motor hunting occurs.
Motor Performance Fine-Tuning on page 268
for details.
Hunting occurs at start.
Increase the S-curve time at the start of acceleration (C2-01).
Too much current is flowing through the drive.
• Enter the correct motor code for the PM motor being used into E5-01.
• For special-purpose motors, enter the correct data to all E5 parameters according to the test report provided for the
motor.
Cause
Possible Solutions
The Run command was not issued again when power was restored.
• Check the sequence and wiring that has been set up to enter the Run command.
• A relay should be set up to make sure the Run command remains enabled throughout any power loss.
The relay that is supposed to maintain the Run command has been
switched off.
Check wiring and circuitry for the relay intended to keep the Run command enabled.