Wuxi Lanhai Electric Motor Co.,Ltd
Add: 4#, Tianshi Road Shitangwan Town, Wuxi, Jiangsu, China
Reasons and Prevention of Motor Single Phase Operation
In modern industrial production, the application of electric Motors is very extensive. However, in the production, electric Motors occupy a large proportion of production due to the burning of electric Motors due to the lack of phase operation. How to reduce the occurrence of these problems and improve the efficiency of electric Motors is A question worth pondering seriously. Based on my years of practical work and relevant information, I hereby put forward measures for preventing single-phase Motor running. For reference and inadequacies only, I would like to offer my valuable suggestions.
First, the Motor caused by single-phase operation and preventive measures
1, fuse blown
⑴ fault fuse: mainly due to the main circuit of the Motor single-phase ground or short circuit caused by the fuse blown.
Preventive measures: Choose to adapt to the surrounding environment of the Motor and the correct installation of low-voltage electrical appliances and wiring, and to be regularly checked to strengthen routine maintenance and repair, and eliminate all kinds of hidden dangers.
⑵ non-fault fuse: mainly the improper selection of melt capacity, capacity is too small, start the Motor, the impact of the start-up current, the fuse blows.
Fuse non-fault fuse can be avoided, not one-sided that can avoid the Motor starting current case, the melt capacity try to choose smaller, so as to be able to protect the Motor. We must make it clear that the fuse can only protect the Motor from single-phase to ground and short-circuit fault, it must not be used as the Motor overload protection.
2, the correct choice of melt capacity
General melt rated current selection formula is: Rated current = K × Motor rated current
⑴ larger heat-resistant fuse (filler type) K value can choose 1.5 ~ 2.5.
⑵ heat capacity smaller fuse K value can choose 4 ~ 6.
For the Motor with a different load, K value is also different, such as the Motor directly drives the fan, then the value of K can choose larger, such as the Motor load is not large, K value can choose smaller, depending on the specific load of the Motor To decide.
In addition, the fuse must be in good contact with the melt holder, otherwise it will cause contact with the heating, the melt by external heat caused by non-fault fuse.
In the process of installing the Motor, should be the proper wiring and proper maintenance methods.
⑴ for copper, aluminum connection as far as possible the use of copper and aluminum transition joints, such as the absence of copper and aluminum joints, copper joints can be linked out of tin.
⑵ For larger plug-in fuses, padded copper sheet (0.2mm) can be added at the wiring, so the effect will be better.
Second, single-phase operation of the analysis and maintenance
According to the different Motor wiring, under different loads, the current occurs single-phase operation is also different, therefore, to take the protection of different ways.
For example: Y phase wiring Motor occurs single-phase operation, the Motor phase current is equal to the line current, the size of the load with the Motor.
When the △ wiring Motor disconnected, the Motor becomes ∨ type wiring, phase current and line current are proportional to the increase in Motor load, the rated current load, the two-phase current should be increased 1.5 times, a phase line Current increased to 1.5 times, the other two-phase line current increased √3 / 2 times.
When the delta-type wiring of the Motor is disconnected, the two-phase Motor windings are connected in series with the third winding in parallel with the two-phase voltage. The line current is equal to the sum of the windings parallel current and proportional to the Motor load In the case of rated load, the line current is increased by 3/2 times, the current in the two windings in series is unchanged and the current in the other phase is increased by 1/2 times.