1. Pay attention to current, voltmeter and flow of water, make sure the pump operate during the rated operating condition.
2. Adjust the flow and dynamic head by the value, overload operation is forbidden. Stop operating immediately when it happens as below:
（1） Rated voltage，but the current is 20% more than rated current.
（2） Supply voltage higher than 400V or lower than 360V.
（3） Rated dynamic head, flow of water decreased a lot than normal condition.
（4） Insulation resistance lower than 0.5 MΩ.
（5） Lower dynamic water level on pump inlet.
（6） Electrical equipments and circuit don’t meet the requirements.
（7） A suddenly sound or a strong vibration of pump.
（8） Frequent trip of protection switch.
3. Pay attention to instrument frequently, check electrical insulation resistance of electrical equipments every half a month, and the value should not be lower than 0.5 MΩ.
4. Conduct overhaul and protection every irrigation and drainage period (2500 hours), and replace broken vulnerable part.
5. Lifting, load and unload of pumps:
（1）Cut off power supply, remove cable wiring.
（2）Disassemble outlet pipes, gate valve and elbow pipes with installation tool, lift the pump with clip and take out the manhole cover, then clamp the next delivery pipe with another clip，disassemble the segment one by one until lifting the pump outside the well. (During the process of lifting and disassemble, when it get stuck, try to move up, down, left and right to get rid of the position then keep going with safety).
（3）Remove wire-protected plate and water strainer, cut off the cable in the layup of lead wire and three-core cable or ribbon cable.
（4）Remove the locking ring on the coupling , screw off the fixed screw, dismantle the connecting bolt, separate the motor and pump.
（5）Pour the water out of motor.
（6）Disassembling of pump:
Remove the water inlet by wrench, impact the taper sleeve by replacer on the bottom of pump. After the impellers got loose, take out the impellers and taper sleeve, remove the blower inlet casing, then remove the upper blower inlet casing and check valve.
（7）Disassembling of motor：
Remove the motor seat, thrust bearing, thrust plate, inferior bearing seat, coupling base , sand proof controller one by one . Take out the rotor , remove upper bearing seat and stator.
6. Assembling of electric pump:
Check and clean up rust and mud of components before the assembling, coat grease on every mating surface, coat lead oil on the junction of screw thread.
（1）Assembling sequence of motor：
stator→inferior bearing seat→rotor→thrust plate→nut→thrust bearing→motor seat→upper bearing seat→framework oil seal→coupling base. Adjust the stud, make motor shaft extension meet the specified requirements, then install pressure balance membrane, pressure adjusting spring and cover.
（2）Assembling sequence of pump：
Fix the shaft and water inlet on the mounting base, fix the impeller and thrust plate on the shaft by replacer, then install blower inlet casing, impeller……then install the upper blower inlet casing and check valve.
When assembling motor and pump whose grade is less than grade eight, firstly install 3 or 4 gaskets(3~3.5mm) evenly on the contact plane between water inlet and upper bearing seat.
Then install nuts evenly, install coupling, pump shaft, clamp screw and locking ring, fix the impeller and taper sleeve on pump shaft by replacer, then install blower inlet casing, impeller……and upper blower inlet casing.
After assembling the pump, loosen the nuts, take out the gaskets, and tighten the nuts evenly, then shift the pump on the coupling, the shifting must be even.
7. Preservation of pumps
If the pump will be left unused for a long period of time, pour out the waters in the motor in time, clean up the surface, coat anti-rust oil, and place the pump in a clean, dry, non-corrosive situation. If the lumen of motor is full of water, it’s strictly prohibited to be placed in a circumstances that the temperature is below 0℃，otherwise the water in the lumen have to be discharged to prevent motor being frost-cracked.
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