The following are the tips summarized by experienced master according to his own maintenance technology.
1, to quickly find out the electrical fault to have the necessary basic knowledge. For example, it is a prerequisite to know the structure, performance and use of electrical components commonly used in electrical equipment.
2. Be familiar with the electrical schematic diagram of electrical equipment and the location and relationship of the corresponding electrical components in the circuit diagram;
3. Skillful use of various instruments and meters is an unavoidable topic for maintenance electrician. For example, commonly used measuring pens, multimeters, clip-on ammeters, megohmmeters, oscilloscopes, etc. should be familiar with their usage methods, as well as their structure, performance and uses.
4, in order to quickly find electrical faults, we electrician maintenance personnel should meet the requirements of knowing and meeting.
5. Under normal circumstances, it will take longer to find faults than to repair them. The process of finding electrical faults is actually a process of combining physical strength with mental strength, so our maintenance personnel should be good at grasping the essence of things through phenomena;
5. We should master certain methods in maintenance technology and skills, such as the "six diagnosis" method commonly used by our electrician maintenance personnel (oral inquiry, visual inspection, ear inspection, nose smell, hand touch and surface measurement), the "three first and three later" method (first easy and then difficult, first moving and then static, first power supply and then load) and the "nine methods" (logical analysis, short circuit method, open circuit method, fault reappearance method and disturbance method).
Because the three-phase voltage imbalance will produce a reverse-sequence rotating magnetic field on the stator of the induction motor, the induction motor will run under the action of positive and negative magnetic fields at this time. Because the positive-sequence rotating magnetic field is much larger than the reverse magnetic field, the rotating direction of the motor rotates in the positive-sequence direction, but the rotor reverse-sequence resistance is very small, so the reverse-sequence current is large, and the existence of reverse-sequence current and magnetic field will produce a larger braking distance, which will reduce the power.