Analysis of the causes of burned motor coils in shielded pumps
Thread Content
Our factory has a Dalian Empire shielded pump used for handling ammonia solution; the pump stops operating during operation. Upon disassembly, it was found that the shielding sleeve was bulged and the motor lacked insulation. The maintenance team was contacted to repair the motor stator; after replacing the shielding sleeve, the motor operated for three months before burning out again. When the terminals were opened, ammonia was found inside, but there were no visible scratches or leaks on the shielding sleeve, and no leaks were detected during pressure testing. This time, it was suspected that there was a very small leak at the welding seam of the shielding sleeve, which prevented pressure from being applied. The stator coils were repaired once more, but the motor burned out again within less than 3 days of operation. Inspection revealed no signs of wear on the shielding sleeve, and no leaks could be identified through pressure testing as well. Could everyone help analyze the reason? I think liquid getting into the stator coil can only have entered through the shielding sleeve, but we fail to locate the leak point every time. Some people have analyzed that it might be due to cracks on the sealing surfaces at both ends of the motor, which allowed liquid to seep into the motor stator; however, such leakage points cannot be detected using conventional pressure testing methods. We first supplied oxygen to 2 kg at the terminal, filled the pump chamber with water, and no bubbles emerged. Then, water was pumped into the pump chamber using workwear until a pressure of 30 kilograms was reached; after holding that pressure for 24 hours, it was found that the pressure had dropped to 24 kilograms. However, it’s not possible to determine where the leak is. I would appreciate it if everyone could offer some advice. Thank you.
Although no leakage points could be found, there is a strong suspicion, so simply replace the stator shield and try again.
The shielding sleeve has been replaced 3 times, but the coil still burns out
You can do a penetration test to see if it can be detected
Could I get in touch with you? I have some questions I’d like to ask
The three repairs you’ve had done cannot be considered sequentially; for each repair, it’s necessary to perform leak testing on the shielding sleeves as well as the flange areas. It seems that the qualified level of your repair service provider is insufficient
After pressurizing the pump chamber to 30 kilograms, the pressure was reduced to 24 kilograms. If it leaks into the motor through the shielding sleeve, it’s impossible to confirm that, right?
Recently, one of our shielded pumps also had poor insulation; upon opening it, it was found that liquid was entering beneath the wiring box. Meanwhile, PT testing showed that there was no problem with the shielding sleeve. What you’ve described seems very similar to our situation, and the repair team believes that the weld at the shielding sleeve is leaking
Recently, one of our shielded pumps also had poor insulation; upon opening it, it was found that liquid was entering beneath the wiring box. Meanwhile, PT testing showed that there was no problem with the shielding sleeve. What you’ve described seems very similar to our situation, and the repair team believes that the weld at the shielding sleeve is leaking
Ammonia has a certain corrosive effect on the shielding sleeve! But it broke just three days after you replaced it – the repair shop you turned to is not reliable! It is recommended to seek repair from a reputable manufacturer, and convey the issues you are facing to them during the repair process. Our company has been engaged in the assembly and repair of shielded pump systems for many years; please contact me at 15762830355 if necessary