Determine the correct rotation direction of the motor
It is necessary to determine the rotation direction of the motor. Nowadays, many types of submersible sewage pumps can discharge water both when rotating in one direction and when rotating in the opposite direction. However, when rotating in the opposite direction, the water output is smaller and the current is higher. If the rotation lasts for a long time, it will damage the motor windings.
2. Prevent abnormal power-on due to abnormal power voltage
Because the low-voltage power supply line is quite long, it is common for the voltage at the end of the line to be too low. When the phase voltage drops below 198 volts and the line voltage drops below 342 volts, the speed of the submersible sewage pump motor decreases. When it fails to reach 70% of the additional speed, the centrifugal switch will close, causing the starting circuit to be energized for a long time and generating heat, which may even damage the windings and capacitors. On the contrary, if the voltage is too high, the motor will overheat and damage the windings. Therefore, during the operation of the submersible sewage pump, the operator must constantly monitor the power supply voltage value. If it is below the additional voltage by 10% or more, or above the additional voltage by 10% or more, the motor should be stopped, the cause should be identified and the fault should be eliminated.
3. Insulation resistance requirements for the cable line installation and the submersible sewage pump
When installing the submersible sewage pump, the cable should be suspended, and the power line should not be too long. When lowering or lifting the submersible sewage pump, do not apply force to the cable to prevent it from cracking. During operation, do not submerge the pump in the mud; otherwise, it will cause poor heat dissipation of the motor and damage the motor winding. When installing, the insulation resistance of the motor should not be lower than 0.5 megohms.
4. Leakage protection device
The leakage protector is also known as the life-saving device. Its function can be understood from the words "leakage protector". Since the underwater sewage pump operates in water, a simple leakage can lead to power loss and even cause electric shock accidents. If a leakage protector is installed, as long as the leakage value of the underwater sewage pump exceeds the action current value of the leakage protector (usually not exceeding 30 milliamperes), the leakage protector will cut off the power supply of the sewage pump, ensuring safety and preventing leakage and power waste.
5. Prevent frequent switching
Do not frequently turn on and off the submersible pump. This is because when the electric pump stops running, backflow occurs. If you start it immediately, it will cause the motor to be overloaded and result in excessive starting current, which could damage the winding of the motor. Because the current is very high during startup, frequent startups will also damage the winding of the submersible sewage pump motor.
6. Don't let the underwater sewage pump operate at an overloaded capacity for an extended period of time.
To prevent the submersible pump from operating at an overload for an extended period, do not pump water with high sediment content and always check whether the current value is the one specified on the nameplate. If you find the current is too high, stop the machine for inspection. Additionally, the running time of the electric pump in the dehydration mode should not be too long to avoid overheating of the motor and causing its damage.
7. Focus on regular maintenance
It is necessary to frequently inspect the motor. If cracks are found on the lower cover, or if the rubber sealing ring is damaged or ineffective, they should be replaced or repaired in time to prevent water from entering the submersible pump.
Pay attention to the proper use of the underwater sewage pump maintenance device and carry out regular maintenance. This will significantly extend the service life of the underwater sewage pump.
