Notes for Submersible Pumps
[Power supply voltage abnormal do not turn on]
Because of the long low-voltage power supply lines in rural areas, it is common that the terminal voltage of the lines is too low. When the phase voltage is lower than 198 volts and the line voltage is lower than 342 volts, the speed of submersible pump motor decreases. When the rated speed is less than 70%, the start-up centrifugal switch will close, causing the start-up winding to be heated for a long time and even burned out the windings and capacitors. On the contrary, overvoltage causes overheating of the motor and burns out the windings. Therefore, in the operation of submersible pump, the operator must always observe the voltage value of power supply. If the voltage is lower than 10% of rated voltage and higher than 10% of rated voltage, the motor should stop running, find out the causes and troubleshooting.
[Installing leakage protectors]
Leakage protector is also called life-saver. Its function can be understood from the words "life-saver". Because the submersible pump works underwater, it is easy to cause electric energy loss or even electric shock. If there is a leakage protector, as long as the leakage value of the submersible pump exceeds the action current value of the leakage protector (generally not more than 30 mA), the leakage protector will cut off the power supply of the submersible pump, avoid the leakage of electricity and waste electricity, and ensure safety.
[Avoid frequent switching]
Do not switch the stainless steel submersible pump frequently, because the pump will produce reflux when it stops running. If it is switched on immediately, it will start the motor load, resulting in excessive starting current and burning the winding. Because the starting current is very high, frequent starting will also burn the motor winding of submersible pump.
[Don't let submersible pumps overload for a long time]
In order to avoid long-term overload of submersible pumps, do not pump water with large sediment content and observe whether the current value is specified on the nameplate at any time. If it is found that the current is too large, it should be stopped to check. In addition, the operation time of the electric pump dehydration should not be too long, so as to avoid the motor overheating and burning.
[The motor should rotate in the right direction]
It is necessary to find out the direction of motor rotation. There are many types of submersible pumps that can produce water when they are in forward and reverse rotation. However, when they are in reverse, the water output is small and the current is large, and the motor winding will be damaged if they are reversed for a long time.
[Insulation Resistance Requirements for Cable Installation and Submersible Pumps]
When installing a submersible pump, the cable should be overhead and the power cord should not be too long. Do not force the cable when submersible pump is put into water or put forward, so as not to cause the breakage of power cord. Do not sink into mud when submersible pump works, otherwise it will cause motor to heat poorly and burn motor windings. Installation, the insulation resistance of the motor should not be less than 0.5 megohm.
[Check on duty to find problems and repair them in time]
Usually, the motor should be inspected frequently, such as cracks in the lower cover, damage or failure of rubber sealing ring, etc. It should be replaced or repaired in time to avoid water infiltration into submersible pumps. Submersible pumps can also be used for fountain landscape, hot water submersible pumps for hot spring bathing, deep wells for groundwater extraction, rivers, reservoirs, water canals and other water lifting projects. It is mainly used for farmland irrigation and human and animal water in high mountain areas. It can also be used for central air conditioning cooling, heat pump unit, cold pump unit, city, factory, railway, mine and site drainage. The general flow rate is (10m3 ~ 650m3) per hour and the lift can reach 1500 meters. Included: Submersible pumps are compact and portable, and play an important role in rural production and life. The following points should be paid attention to in use:
1. When purchasing stainless steel submersible pumps, attention should be paid to their pump type, pump flow and pump head. If the selected specifications are inappropriate, it will not be able to obtain enough water output, and can not play the efficiency of the unit. In addition, the direction of rotation of the motor should be made clear. Some types of submersible pumps can produce water when they are in positive and reverse rotation, but when they are in reverse, the output water is small and the current is large, and their reverse rotation will damage the motor winding. In order to prevent electric shock accident caused by leakage of submersible pump when working under water, leakage protection switch should be installed.
2. When installing submersible pumps, the cable should be overhead and the power cord should not be too long. When the unit launches, do not force the cable, so as not to cause the breakage of the power cord. Submersible pump should not sink into mud, otherwise it will cause bad heat dissipation and burn motor windings.
3. Avoid starting at low voltage as far as possible. Power supply voltage and rated voltage can not be 10% different, too high voltage will cause motor overheating and burning windings, too low voltage will reduce motor speed, if not up to 70% of the rated speed, the start centrifugal switch will close, resulting in long-term power-on of the start winding and even burning out the windings and capacitors. Do not switch on the motor frequently, because the pump will produce backflow when it stops running. If it is switched on immediately, it will start the motor load, resulting in excessive starting current and burning the winding.
4. Never let the submersible pump run overloaded for a long time. Don't pump water with large sediment content. The time for the submersible pump to dehydrate should not be too long, so as not to overheat the motor and burn it down. During the operation of the unit, the operator must observe whether the working voltage and current are within the specified value on the nameplate at any time. If they do not meet the requirements, the motor should stop running, find out the causes and troubleshoot.
5. Check the motor more often in peacetime. If cracks are found in the lower cover, damage or failure of rubber sealing rings, they should be replaced or repaired in time to prevent water from seeping into the machine.