Submersible pump is an important equipment for deep well water lifting. When in use, the entire unit dives into the water to extract groundwater to the surface, which is used for domestic water, mine rescue, industrial cooling, farmland irrigation, seawater lifting, ship loading, and can also be used for fountain landscapes. Hot water submersible pumps are used for hot spring bathing, as well as for extracting groundwater from deep wells. They can also be used for water extraction projects such as rivers, reservoirs, and canals. Mainly used for farmland irrigation and water supply for people and livestock in high mountain areas, it can also be used for central air conditioning cooling, heat pump units, cold pump units, urban, factory, railway, mining, and construction site drainage. The general flow rate can reach 5-650m ³/h, and the head can reach 10-550 meters. Submersible pumps often suffer from motor winding burnout due to water shortage in the pool.
In response to this situation, today we have compiled several protective measures for submersible pumps: water shortage protection, motor leakage protection, oil chamber leakage protection, insulation resistance protection, winding overheating protection, bearing overheating protection, etc.
Safety protection methods for submersible pumps
1. Prohibit abnormal power supply voltage startup
Due to the long length of low-voltage power supply lines, it is common for the terminal voltage of the lines to be too low. When the phase voltage is lower than 198 volts and the line voltage is lower than 342 volts, the speed of the submersible pump motor decreases. When it does not reach 70% of the rated speed, the centrifugal switch will close, causing the starting winding to be energized for a long time and generate heat or even burn out the winding and capacitor. On the contrary, excessive voltage can cause the motor to overheat and burn out the windings. Therefore, during the operation of the submersible pump, the operator must observe the power supply voltage value at all times. If it is below 10% of the rated voltage and above 10% of the rated voltage, the motor should be stopped to identify the cause and eliminate the fault.
2. Confirm the correct rotation direction of the motor
The rotation direction of the motor should be clarified. There are many types of high head submersible pumps that can produce water in both forward and reverse directions, but the water output is small and the current is high in reverse. If the reverse time is long, it will damage the motor winding.
3. Cable installation and insulation resistance requirements for submersible pumps
When installing a submersible pump, the cable should be overhead and the power line should not be too long. When diving or lifting the submersible pump, do not put force on the cable to avoid causing the power line to break. When the submersible pump is working, do not sink into the mud, otherwise it may cause poor heat dissipation of the motor and burn out the motor winding. During installation, the insulation resistance of the motor should not be less than 0.5 megohms.
4. Avoid frequent switching
Do not frequently turn on and off the submersible pump, as it will generate backflow when the electric pump stops. If it is turned on immediately, it will cause the motor load to start, resulting in excessive starting current and burning out the winding. Due to the high current during startup, frequent startups can also burn out the windings of the submersible pump motor.
5. Installation of leakage protector
Leakage protector, also known as life protector, its function can be understood from the three words life protector. Because submersible pumps work underwater, they are prone to electrical leakage, which can cause energy loss and even lead to electric shock accidents. If a leakage protector is installed, as long as the leakage value of the submersible pump exceeds the operating current value of the leakage protector (generally not exceeding 30mA), the leakage protector will cut off the power supply of the submersible pump to ensure safety and avoid leakage and energy waste.
6. Prohibition of long-term overload operation of submersible pumps
To avoid long-term overload operation of submersible pumps, do not pump water with high sediment content and observe whether the current value is within the specified value on the nameplate at any time. If excessive current is found, stop the machine for inspection. In addition, the dehydration operation time of the electric pump should not be too long to avoid overheating and burning out the motor.
7. Pay attention to daily maintenance
Regularly check the motor. If cracks are found on the lower cover, damaged or ineffective rubber sealing rings, etc., they should be replaced or repaired in a timely manner to prevent water from seeping into the machine.
8. Try to avoid starting up at low voltage as much as possible
The power supply voltage should not differ from the rated voltage by more than 10%. If the voltage is too high, it can cause the motor to overheat and burn out the winding. If the voltage is too low, the motor speed will decrease. If it does not reach 70% of the rated speed, the centrifugal switch will close, causing the starting winding to be energized for a long time and generate heat or even burn out the winding and capacitor. Shanghai SuNeng Pump Valve Reminder: Do not frequently switch the motor, as it will generate backflow when the electric pump stops. If the motor is started immediately, it will cause the motor load to start, resulting in excessive starting current and burning out the winding.
