Submersible pumps are a kind of common used tool for draining and supplying water, they are widely used for all sorts of applications such as industrial and domestic use. But because of complicated using conditions, the fault rate of them are relatively high. Here, we will discuss the common fault of submersible pumps and way to repair.
Electric leakage is the most common fault that occurs to most pumps.
Phenomenon: When switch pole is closed, the leakage protector closes down automatically.
Reason: 1. Water flows into pump body and then leads to electric leakage of motor winding
2. Cable gets broken, and water flows into cable
Precaution: equip pump with electric leakage protective switch when it is working, meanwhile to set grounding wire in safe conditions
Main reason of oil leakage is badly worn of seal box for lack of mechanical oil. Then sealing elements are worn or become natural aging, which leads to bad sealing condition or oil leakage. When oil spot occurs near inlet, or the root of cable becomes oiling, it represents oil leakage in motor.
Impeller not working when pump is on
Check if switch is on, check the condition of line pressure drop, fuse and wire. If AC sound can be heard when pump is on, but impeller is not working, turn off switch immediately and check if something blocked inlet, then move impeller to see if rator is blocked down. When it happens, dissemble pump and check whether bearing ball get broken at the bottom of rator or not. If impeller can be moved but still not working, perhaps the bearing is badly worn down.
Flow rate of water pump is too low
- Check if pump rotates in wrong direction
- Dissemble pump and check if rator is moving flexibly.
- If rator moves when pump is on, check if bottom bearing gets loosen with shaft. When rator gets down, small output power will directly lead to small flow rate.
Resolution: Set proper grommet between rator and shaft to make rator move upward.
Pump not working
Phenomenon: a. when pump is on, motor is not working and sound no voice.
Resolution: Check the working conditions of power supply, electric line and fuse, motor stator winding gets burned down if nothing wrong occurs to them.
b. Motor is not working but working noisy can be heard when pump is on
Reason: 1. One of phase between power supply line and stator winding is not working
2. Electric pressure is too low. Reason of it may be power pressure gets too low, cable line is too long but cross section is too small.
c. Something block in pump body and shaft bearing gets blocked down, check and clean pump body immediately when it occurs.
d. Starting capacity is not working. When pump is on, noisy can be heard but motor is not working, move impeller lightly, if pump can rotate immediately, then starting capacity is broken.
Motor is burnt down
Reason: 1. One phase in three phase AC circuit stopping working for too long.
2. Head of pump is too large, results in long-term overload working of motor.
3. Frequent start of water pump makes temperature of motor too high.
4. Shaft bearing gets broken
5. Temperature of working water is too high, which results in poor heat dissipation.