Troubleshooting 3-Phase Pump Failures: Causes and Solutions | Expert Tips

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In summary, the conversation discusses a situation where a "non-clogging Submersible" pump, which has been in service for 20+ years, is being replaced and experiencing catastrophic failures. The new pumps have the same rating as the old ones and there have been no changes to the electrical system. However, the pumps' housing is being blown apart and it is suspected that the explosions may be coming from the case ground connection. The pump is used in a sewage system and the explosions are hard to describe, but they seem to be an electrical fault. It is suggested that overheating may be the cause of these failures.
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livewireca
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Here's the situation. We have tried to replace a "non-clogging Submersible" pump that has been in service for 20+yrs and are experiencing catistrophic failures. The new pumps are the same rating as the old (as far as nameplate data goes) and nothing has changed to the electrical system. The electrical feed consists of a wye-delta transformer to give 240VL-L, with a tap off of one of the windings to give 120L-N... leaving C phase as the bastard-leg. However this should have no impact on the pump as it is 240V 3phase. The pumps housing are being blown apart and it appears that source of the "explosions" may be coming from the case ground connection, but it is difficult to tell. We've gone through 3 pumps from two manufacturers. We've also just added line monitoring to check for harmonics, voltage & current etc. And have only noticed so far that the voltage dips during startup, which is normal. These pumps run for a length of time before failing. Here is the nameplate specs from one pump:
5HP, 208/230V, 3ph, 60Hz, 1750RPM, FLA 17.0/16.0, Ins.Class B, Code B D, Impeller Dia 7.00
And some info from the supply panel that feeds the pumps (located btw the pole transformer and pump):
3.7kW-5HP, 1745RPM S1, 3ph, 60Hz, Yser460/Y//230KV 6.8/14A cos 0.81
Any information would be greatly appreciated as we are scratching our heads with this one.
 
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  • #2
What exactly are you using the pump for? My background in electrical is minimal (hence I lurk on these threads for learning purposes :)) but I do a lot of work with large hydraulic systems and have seen all kinds of pump failures in this area.
You're also quite vague on what these 'explosions' are. Are they orginating in the material being pumped or from somewhere in the pump electrical system? You say they originate from the case ground connection but arent sure.
 
  • #3
The pump is used in a sewage system, and this is why we require a non-clogging design. The "explosions" are hard to descibe. I haven't witnessed what has happened, and have only viewed the condition of the pump(s) when they have been taken out of service due to failure. The outer case of these pumps that have failed have large pieces missing as if the side has been blown off. One of the pumps shows the ground that went to the case showing signs of burning/arcing and points to when the case used to be... In my opinion it appears to be an electrical fault of some kind. There doesn't appear to be any problem at the mechanical end of these pumps.
 
  • #4
Okay, I see what you mean. I just hear a 'submersible' pump and 'explosion' and I automatically think some type of caviation phenomenon occurring. Doesnt seem so in this case.
 
  • #5
Stop serving beans.
 
  • #6
If I had to hazard a guess, I'd say overheating was a likely culprit. Whether this heating is due to incorrect voltages or insufficient cooling, I can't say. I'm imagining what's happening here is the unit gets all hot inside, the insulation begins to break down and BLAMMO you get an arc fault blast.
 

What is a 3phase pump?

A 3phase pump is a type of pump that operates on three-phase electrical power. This means that it has three separate power sources, which allows it to run more efficiently and power larger pumps than single-phase pumps.

How do 3phase pumps work?

3phase pumps work by using three alternating currents of electricity to power the pump's motor. These currents are evenly spaced apart, and each one is out of phase with the others. This allows the pump to draw more power and run more efficiently than single-phase pumps.

What are the most common causes of 3phase pump failures?

The most common causes of 3phase pump failures include power surges, incorrect wiring, mechanical wear and tear, and insufficient lubrication. Other potential causes could include overheating, clogs or blockages, or faulty motor components.

How can 3phase pump failures be prevented?

To prevent 3phase pump failures, it is important to properly maintain the pump by regularly checking for wear and tear and ensuring that it is properly lubricated. It is also important to use a surge protector to protect against power surges and to ensure that the pump is wired correctly.

What should I do if my 3phase pump fails?

If your 3phase pump fails, the first step is to diagnose the problem. Check for any visible issues, such as clogs or blockages, and make sure the pump is receiving power. If you are unable to determine the cause of the failure, it is best to consult a professional for repairs or replacement. Preventative maintenance can also help avoid future failures.

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