Submersible pump safety precautions

Submersible pumps often cause burnout of the motor windings due to lack of water in the basin. In view of this situation, the submersible pumps have added several protection measures: water shortage protection, motor leakage protection, oil chamber leakage protection, insulation resistance protection, winding overheat protection, and bearing overheat protection.

1. It is forbidden to turn on the power supply voltage abnormally. Since the low-voltage power supply line is relatively long, the voltage at the end of the line is often 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 the rated speed is less than 70% of the rated speed, the starting centrifugal switch will close, causing the starting winding to be electrified for a long time and generate heat or even burn out. Windings and capacitors. Conversely, excessive voltage causes the motor to overheat and burn out the winding. Therefore, during the operation of the submersible pump, the operator must observe the power supply voltage at any time. If it is less than 10% of the rated voltage and more than 10% of the rated voltage, the motor should be stopped to find out the cause and remove the fault.

2, confirm the correct direction of rotation of the motor should find out the direction of rotation of the motor, there are many types of submersible pumps can be out of water when the forward and reverse rotation, but the reverse flow of water is small, the current is large, the long reversal time It will damage the motor windings.

3. Insulation resistance of cable installation and submersible pump When installing a submersible pump, the cable should be overhead and the power cable should not be too long. When the submersible pump is launched into the water or raised, do not apply force to the cable to avoid breaking the power cord. Do not sink into the mud while the submersible pump is working, otherwise it will cause the motor to dissipate heat and burn out the motor winding. When installing, the insulation resistance of the motor should not be less than 0.5 megohms.

4, to avoid frequent switching Do not frequently switch the submersible pump, this is because the electric pump will generate backflow when stopped, if the immediate boot, the motor load will start, resulting in excessive starting current and burn out the winding. Due to the large current at start-up, frequent start-up can also damage the submersible pump motor windings.

5, the installation of leakage protection The leakage protection device is also called the life-saving device, and its role can be understood from the three words of the life-saving device. Because the submersible pump works underwater, it is easy to cause electrical loss due to electrical leakage and even cause electrical shock. If the leakage protector is installed, as long as the leakage value of the submersible pump exceeds the operating current value of the leakage protector (generally no more than 30 mA), the leakage protector will cut off the power of the submersible pump to ensure safety, while avoiding leakage and wasting electric energy.

6. Do not allow the submersible pump to overload for a long period of time To avoid long-term overloading of the submersible pump, do not pump water with high sediment content and observe at any time whether the current value is specified on the nameplate. If excessive current is found, check the shutdown. In addition, the electric pump dehydration operation time should not be too long, so as not to make the motor overheated and burned.

7, pay attention to daily maintenance usually more than check the motor, if found under the cover cracks, rubber seal ring damage or failure, etc., should be promptly replaced or repaired, in order to waterproof into the machine.

8, try to avoid the boot voltage at low voltage and the rated voltage can not differ by 10%, the voltage is too high will cause the motor to overheat and burn out the winding, the voltage is too low the motor speed decreases, such as less than 70% of the rated speed, start The centrifugal switch will close, causing the start winding to be energized for a long time and heat or even burn out the windings and capacitors. Do not switch the motor on and off frequently. This is because when the electric pump stops rotating, it will generate back flow. If it is turned on immediately, the load of the motor will start, causing the starting current to be too large and the winding to burn out.

(Source: Pump)

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