Applicable Systems
VF-AS1
Symptoms
The VF-AS1 reports an under-frequency fault. The output frequency dropped below the minimum configured frequency limit during operation.
Possible Causes
- Frequency command dropping below the minimum frequency setting
- Motor load causing speed reduction below the minimum frequency
- Minimum frequency parameter set incorrectly for the application
Troubleshooting Steps
- Step 1: Check the frequency command for values below the minimum setting
Command is above the minimum frequency - Step 2: Verify the minimum frequency parameter is set correctly
Minimum frequency is appropriate for the application - Step 3: Adjust the process to maintain frequency above the minimum
Output frequency stays above the minimum
How to Reset
To reset: Increase the frequency above the minimum limit, then reset.
Source: Toshiba VF-AS1 Inverter Manual, Toshiba Mitsubishi-Electric Industrial Systems
Category: PLC & VFD