Feature of electric motors for industrial use, along with increased efficiency, is more efficient cooling due to more surface area (20 – 30%). Consequently, they are significantly less sensitive to low voltage, phase unbalance and lack of cooling (caused by sediments on the motor caused by poor water quality). In addition, industrial electric motors more resistant to corrosion. It should be noted that the highest reliability of industrial electric motors have purpose, the protection of which is carried out mri device 75 or mp block 204. The asymmetry of the voltage and current is known, with minimal asymmetry current reaches the maximum efficiency of the motor and the longest period of his service. That is why the important uniform load on all phases. In theory, the same rated voltage must be applied to all three phases. As a rule, near the low-voltage transformers and occurs.
Note, however, that to prevent the raising or lowering the voltage on some phases of the network at full load all the single-phase units should be evenly distributed over three phases. This should be done, because such devices often operate in the mode of frequent on / off cycles and may cause the asymmetry (bias) phases. Phase imbalance can be caused by the asymmetry current in the lines elekroperedach, as well as worn or oxidized contactors. For a possible asymmetry in the chain need to enable the motor to the network to consult with representatives of the Utility Industry. Current asymmetry should not exceed 5%, while using the remote cu 3 – 10%.