How To Choose And Install Agricultural Submersible Pumps

Feb 08, 2025

There are several points to note when choosing agricultural submersible pumps:
① Choose a merchant. Attention should be paid to purchasing from sales points or specialty stores recognized by the agricultural machinery department and requesting formal invoices. Otherwise, if quality problems arise, users will be helpless.
② Select the number of power phases. Whether to choose a single-phase pump or a three-phase pump should be determined based on the local power supply situation, and three-phase electric pumps should be preferred wherever there is a three-phase power supply. This is because compared to three-phase pumps, single-phase pumps of the same specifications have smaller volume, lighter weight, and less vibration, so choosing a three-phase pump is more economical.
③ Select parameters. The key to choosing a submersible electric pump is to determine parameters such as flow rate and head of the pump. The selection of pump flow rate should be adapted to the inflow and consumption of the water source, as well as the economic conditions of the household, and should be treated on a case by case basis. It is best for users to choose a lift that is close to the lift on the water pump nameplate in order to achieve the highest efficiency. But it is not required to be absolutely equal. Generally, a deviation of no more than 20% can work in a relatively energy-saving situation. If the selected water pump has a too small head, a low head pump is used for high head work, that is, a small horse pulling a large truck. Even if it can pump water, the amount of water will be very small. At the same time, due to motor overload, if the motor runs for a long time, the temperature of the motor will rise, and the insulation layer of the winding will gradually age, and even burn out the motor; The head of the water pump is too high. High lift pumps are used for low lift work, such as pulling small cars with large horses, which wastes electricity and equipment resources.
⑤ Test the quality. The motors of submersible electric pumps have three types of structures: water filled, oil filled, and shielded. Generally, water filled motors are the most widely used. Before using this water pump, both water injection hole bolts must be unscrewed, one for water injection and the other for air discharge. After water injection, wait for about 15 minutes until all the air in the motor chamber is discharged before adding clean water. After filling with water, tighten the two water injection bolts. Keep the motor in a sealed state.
After the motor is filled with water, the winding works in the water, and the insulation of the motor can be measured. To measure the insulation resistance, a megohmmeter or shaking meter must be used, and a multimeter cannot be used because the range of the multimeter is limited and it is difficult to measure the insulation resistance between the winding and the ground. After the insulation is qualified, conduct a trial operation test on the water pump.
In places where conditions permit, after filling the motor with water, tighten the water injection bolt to power on the pump for trial operation in the water tank, but it cannot run for a long time. If conditions do not permit, it can be run idle on the well, but the time should not exceed 5 minutes.
There are several points to note when installing agricultural submersible pumps correctly:
⑴ Carefully inspect before installation
Before installing a submersible electric pump, the first thing to check is whether the pump shaft rotates flexibly. If the pump shaft is found to be not rotating flexibly, there is a collision sound, and the pump shaft shakes radially, the fault should be eliminated before installation.
Next, check if the water inlet hose is damaged, and if there are cracks, promptly repair them.
Then check if each fastening bolt is loose and tighten the loose bolts.
Finally, check the insulation resistance of the motor winding and cable of the submersible pump, and only allow installation and use if it is not less than 0.5 megaohms.
⑵ Correct power distribution
The power cord should be selected according to regulations, the cable should be overhead, and the power cord should not be too long. If the distance between the power source and the water pump is far, the cross-sectional area of the wiring cable should be appropriately increased, and the number of joints should be minimized to reduce the voltage drop of the line. Submersible pumps below 10 kilowatts can be started directly, and it is best to use automatic air circuit breakers for control equipment. If such electrical appliances are not available, knife switches can also be used, but appropriate fuses must be installed according to the working current of the submersible pump. Submersible pumps above 10 kilowatts should be equipped with a pressure reducing starter cabinet to protect the safe operation of the submersible pump. The cable needs to be placed in the groove of the flange of the water supply pipe and fixed to the output pipe with a water-resistant binding rope. Do not put force on the cable when diving or discharging the submersible pump to avoid breaking the power cord, and also prevent scratches on the cable during the process of going down the well.
⑶ There should be two levels of leakage protection measures
To ensure safety, a metal rod with a length of more than 1 meter can be buried in a damp ground near the power source or water pump as the grounding body of the submersible pump. Meanwhile,
We also need to install a leakage 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 avoid leakage and ensure safety.
Before entering the water, check the direction of motor rotation because there are many types of submersible pumps that can be operated in both forward and reverse directions
Water, but when reversed, the water output is small and the current is high. If the reversal time is long, it will damage the motor winding. Therefore, before diving the electric pump into the water, first connect the power supply and check if the rotation direction is correct. If the impeller of the three-phase submersible pump reverses, it should be stopped immediately and the contact between any two phases of the three-phase core wire in the cable can be exchanged. The insulation between the group and the ground should not be less than 0.5 megohms.
(5) Set up safety warning signs
To prevent accidents, clear warning signs should be placed near the submersible pump. To ensure safety, personnel and livestock are strictly prohibited from coming into contact with water sources near the outlet of the submersible pump.