Voor elke elektromotor is de elektromotor relatief veilig, zolang de werkelijke stroom van de elektromotor de nominale motor niet overschrijdt.
wanneer de stroom de nominale stroom overschrijdt, lopen de wikkelingen van de elektromotor het risico te verbranden.
Bij driefasige motorfouten is het ontbreken van fase een relatief typisch type fout, maar met de opkomst van beveiligingsinrichtingen voor de werking van elektrische motoren is dit type probleem relatief goed omzeild.
However, once the three phase motor is lack of phase, the winding will have a very short period of time to appear regularly burned fault appearance, different connection, the winding is burned in different patterns, triangle connection of the electric motor winding.
When the phase problem occurs, there will be a phase winding is burned and the other two phases are relatively intact; and star winding, there are two phases of winding burned, the other phase is basically intact
Voor de verbrande wikkeling is de fundamentele reden dat de stroom die deze kan weerstaan de nominale stroom overschrijdt, maar hoeveel deze stroom is, zijn veel internetgebruikers erg bezorgd over het probleem, we proberen het kwantitatief te begrijpen via de specifieke berekeningsformule.
Wat dit aspect van de analyse betreft, zijn er ook een aantal experts die thematische analyses uitvoeren, maar er zijn altijd enkele onmeetbare factoren in verschillende berekeningen en analyses, die zullen leiden tot een grotere huidige verschuiving, die ook een onderwerp van discussie is geworden.
When the electric motor starts and runs normally, the three phase AC power is symmetrical load, and the three-phase current is equal in size and less than or equal to the rated value. When there is a phase disconnection, so that one or two phase line current is zero, the rest of the phase line current will increase the situation.
We take the load during electric operation as the rated load, and analyze the current situation qualitatively from the distribution relationship of winding resistance and torque after phase break.
For the Delta connected electric motor, When it is working under the rated value. The phase current of each group of winding is 1/1.732 times of the rated motor current (line current).
When one phase is disconnected, that is, two phase windings are connected in series and then in parallel with the other phase.
The winding current which bears the line voltage alone will be more than 2.5 times of the rated current.
It will cause the winding to be burned in a short time, while the other two phases winding current is smaller and will be in good condition in general.
For the star-connected electric motor, when a phase is disconnected, the other two phase windings are connected in series with the power supply.
When the load remains unchanged, the disconnected phase current is zero, and the current of the other two phase windings increases to more than two times the rated current, so that the two phase windings overheat and burn up.
But from the analysis of the whole process of phase loss, different windings, different quality state of the winding, the actual situation of the load and other factors, will lead to the change of current is relatively complex, can not be calculated and analyzed from a simple formula, we can only roughly analyze from some limit state and ideal mode.
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