Problems with the frequency converter of the dust removal fan
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The variable frequency drive of the dust removal fan used for coke discharge in our plant is experiencing the following problems: the bypass switch, which is the mains-frequency switch, should not be closed, yet the high-voltage side of the variable frequency drive indicates that it is operating in bypass mode. Attempting to stop the dust removal fan via the computer control system does not work. After the variable frequency drive of the dust removal fan used for coal loading is started, an F25 error message appears. Please, experts, help analyze what could be the cause
If there is nothing wrong with the computer control system software, the most likely cause is a wrong wiring. Other possibilities: There might be an issue with the signal coming from the inverter; it could be a problem with the inverter itself, or it could be a problem with the wiring. It’s also possible that there is an issue with a component within the system – so it’s necessary to check each possibility one by one.
It’s possible that there is an issue with the status of the input from your bypass switch to the PLC; the PLC assumes that the bypass switch is in the closed position. And your inverter may be due to circuit interlock; at this time, there is no main power supply, only the control power supply is active. It’s just a guess, for reference only.
Based on what you’ve described, the problem might lie in the interlock relay between the frequency conversion cabinet and the bypass cabinet; it is recommended that you replace this relay!