1, the quality of the pump body itself. Now many small workshops in the production of small power submersible pumps, both motor performance, sealing, pump body materials, impeller material, impeller cutting size, bearings and so on are not guaranteed, so, no matter where you use it, it is easy to be bad; so choose the quality of the brand with a guarantee.
2, protection mode: submersible pumps in the work, the most common is the pump body impeller has debris clogging or after a long time of use, bearing wear and tear. These two situations will cause the pump body overcurrent (a short period of overcurrent generally does not cause pump failure, but can cause the motor insulation life shortened), if the protection method is appropriate, it will not cause pump failure. Common is the use of circuit breaker heating relay protection mode. This requires electrical designers to be particularly familiar with the selection of circuit breakers and thermal relays, while the circuit breaker can not be a miscellaneous brand. According to personal experience, Wenzhou-produced circuit breakers and thermal relays can never be used, domestic Tianshui 213 Electric Switch Factory, Changshu Switch Factory, Shanghai People's Electrical Appliances Switch Factory (not People's Electric Group ---- this group for Wenzhou people registered in Shanghai, the company, the place of origin is still Wenzhou); foreign brands will not be introduced. After a reasonable selection, it is necessary to consider the setting value, especially in the use of the process of setting the thermal relay, a reasonable setting value will play a protective role, otherwise still can not protect the pump.
3, if the protection of high demand, you can buy motor-specific protection devices, can provide leakage, short-circuit, phase sequence, phase, under-voltage, over-voltage and other protections, in the past, called the "integrated protector". The disadvantage is the high cost. Currently on the market more such products, but still need to pay attention to the brand.