The special cases of 3-phase asynchronous motors
The special symptoms of 3-phase asynchronous motors |
![]() The unloading condition of the motor is normal, in this artcle some special cases are mentioned:1. Unloading motorUnload motor (spin without load) or very weak load, weak currents in the motor that do not harm the engine, but waste resource, and low capacity factor and output, causing waste electrical energy . Therefore, the motor had not better to be worked under load or unload . 2. Short-circuited caseShort-circuited phenomena can be caused by: The insulating resistor of the motor is reduced (due to the damped engine) or due to a mechanical collision that damages the insulation, causing a short circuit among the phases, or the wires of a phase. , or phases. Also please note the following symptoms:When you turn on, rotor can not spin, curent on the windings is very high , if this symptoms is ignored in long time, motor will be broken. This is called short-circuited phenomena 3. Working case with asymmetric voltageIf the 3-phase voltage is installed in an unbalanced motor, in the motor outside the magnetic field (in the same direction as the rotor rotation), or in inverse magnetic field. The magnetic field that causes an inverse torque to rotation direction reducing the torque motor, increasing the loss, electric currents and the heat of motor. The working condition of asymmetric voltages that often occurs in production is the loss of an electric phase. If this situation is not corrected for a long time, the motor will be burnt.
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