Tragedies caused by air compressors
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40 cubic meters per minute air compressor, 250KW motor, Bolete product. At first, the sound was abnormal and muffled, then the unit stopped operating. The main switch of the air compressor did not trip, which caused the switch located in front of the transformer to trip and result in a power outage ； After the contact panel automatically supplied power, workers restarted it without knowing this, which caused another transformer to lose power and led to a blackout across the entire plant, resulting in significant losses. During maintenance, the spool of the air compressor inlet control valve came loose; after it was reinstalled, the machine operated normally upon testing. The questions are as follows: 1. The inlet valve is an automatic pneumatic valve, controlled by a solenoid valve for the air circuit; once it comes loose, can it be assumed that the valve remains in a closed state? Will this cause the air compressor to overload and experience excessive current? 2. Why didn’t the main switch trip, but instead it was the switch in front of the transformer that tripped? It is preliminarily assumed that the high-voltage switch has a shorter response time than the low-voltage switch, which is why it trips before the main switch of the air compressor. Is it correct? 3. The cable and control circuit have been tested separately and show no issues. Are there any other possible issues? Additionally: Our factory has two air compressors; one of them also experienced a shutdown due to tripping a few days ago, but it was the main switch that tripped, and this did not cause a power outage for the transformer. After disassembling and inspecting the intake assembly this time, the machine started up and operated normally. I would like to know what impact the operation of the air compressor’s intake valve has on its performance.
I think that in addition to looking for the cause mechanically, the electrical aspects should also be carefully examined.
It’s probably caused by an incorrect setting of the jump value
There must be an issue with the electrical parameter settings
If the intake valve assembly is damaged, the compressor cannot be powered on; in such a case, the control cabinet will shut down first, and there will be no further shutdown at higher levels. Is there no delay-based trip device installed on it?
Could you explain why damage to the intake valve causing it to fall off can lead to a trip?
I’m not a professional either; I just happened to encounter a similar situation last month. After there was a problem with the intake assembly, the engine started with an obviously abnormal sound. Once it started running, excessive current was generated, causing the engine to shut down. Replacing the intake assembly resolved the issue.
The air compressor that caused the power outage had a detached intake valve stem; after replacing it with one from a backup unit, it operated normally. The unit that was dismantled also tripped two days ago, but after repairing the damaged intake valve and installing it on this unit, it is now operating normally. It indicates that it is related to the intake assembly, but it’s not clear where the specific problem lies.
The reasons that cause the main circuit breaker to trip are either instantaneous low-voltage protection or an overloaded transformer. Would it be safer to install a delayed tripping device on the circuit breaker? I’m not from an electrical engineering field; you can ask the electrical engineers at your company
It belongs to pressure-start operation; when the air compressor starts normally, the intake valve should be completely closed. If it cannot be closed, it is an abnormal condition, usually resulting in motor overload.
Find an electrician; the overcurrent protection setting is incorrect, causing premature tripping