A few days ago, a work in a factory is engaged in the maintenance electrician netizens in communication, is mysteriously, revealed by the fault of the fantastic case: one day, the units used in the workshop a single-phase floor fan stalling phenomenon occurred suddenly, so the net friend to disposal. Tested the fan power supply is normal, just the way along the winding resistance measurement is used with a multi-meter state! As a result, the net friend, of course, determine the fan coil burned, then report to the leadership. But the next day the net friend to work in the process of the patrol was found that by the sentence to burn so incredibly magically the more "eye", is the normal operation! To this phenomenon, the net friend call incredible and ridiculous! But in reaction to the phenomenon, the author to think the net friend are too exaggerated.
Actually the failure phenomenon, the netizens have encountered to self heal because: the floor fan along the winding of a series from multiple temperature switch . Its purpose is to prevent the fan to work long hours, winding temperature rise is too high to cause burning failure. Above the net friend meet failure phenomenon, is the fan to run continuously for a long time, due to high temperature which in turn makes the embedded windings of the double entry temperature switch action, forcing power winding heat and cooling. When the temperature of the winding is cooled to the compound switch after the reset action value, temperature switch back to normal status (mostly normally closed NC state), makes possible the normal use of the fan. After the author will cause tell net friend, he's only an Epiphany - for the sake of seeing is believing, at an excuse to fans to remove the check, the result is as the author said.
Real work, integrated with the above situation is very similar and the traditional motor protector (representative models for the JDB series) : when the protection of the motor in a short period of time often point to move or run overload for a long time after the operation, is usually a motor integrated protector action, then cut off the control circuit, forcing the operation action cannot be performed. In reaction to the phenomenon, some colleagues tend to be busy as a bee, and even individual peers will be considered a motor tao damage happened a comprehensive protection! But it happened in that part of the peer to struggle, comprehensive protector was between themselves back to normal!
With the dual temperature switch failure phenomenon, in front of the motor synthetical protector self-healing phenomenon also has its inherent reasons - two motor use patterns, all can lead to overload fault occurs, thus causing JDB series motor protector internal circuit overload action of actuators: electrolytic capacitor (theoretical basis for the inverse time characteristic) , charging to value, to promote protector action. In colleagues for this busy screening process, electrolytic capacitor is through the lines of protection circuit to discharge. After a period of time after discharge, protector and recover on its own, making operation to continue.
Common faults through the above two cases analysis, it is easy to find the so-called electrical equipment failure phenomenon "eye", all has its internal theoretical basis and the corresponding components support, is not the miracle of the fantastic!
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