Correcting a Motor Speed Deviation Fault (DEV) on an IMPULSE Series 5 Drive
Identify the Fault: The DEV fault is a critical safety-related fault that indicates the drive is not reading the correct motor speed. This fault must be corrected before operating the hoist motion and the VG+ drive.
Understand the Fault: The DEV fault is based on the VG+ drive sensing a difference between the frequency reference (U01-01) and motor speed (U01-05). If these two are off by a factor of 10 percent high or low for a period of three tenths of a second, the drive will trip out on a DEV fault.
Identify the Causes: The information read under motor speed is based on encoder feedback. A problem with the motor speed/encoder feedback could be due to a number of reasons:
Signal Issue: There could be a loss of signal, or electrical noise or interference writing in with the encoder signal itself.
Mechanical Issue: There’s a coupling between the encoder and the motor. Any mechanical means where that coupling becomes loose will result in a DEV fault.
Torque Limits: The drive being at its torque limits can also cause a DEV fault.
Determine the Cause: Go into the monitor mode and look at the standard monitor and trace data. The information that’s loaded into the trace data (U02s) will be the frequency reference, the actual output frequency, and output current. If the drive has put out more current than the motor is rated for, there’s a problem.
Check the parameters: Check the torque limit settings which are loaded in the group C parameters (C07s). The reverse torque limit and forward torque limit are both set to 150%. This is the maximum amount of torque that the drive will allow itself to produce.
Check the Torque Reference: In the monitor menu fault trace, look at the torque reference at fault to see if the drive has reached its torque limit. A percentage torque value above what is programmed into C07-01 or C07-02 will trip out on a DEV fault after two tenths of a second.
Confirm Auto-Tune: If the motor and drive have not been auto-tuned, confirm or perform auto-tune first. If the drive has not been auto-tuned with the respective motor, it does not know what output current relates to what motor torque.
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15 сен 2024
