I would like to ask my friends for advice regarding the issue of excessive current in centrifugal pumps
Thread Content
The centrifugal pump used in the MTBE unit features a semi-open impeller; the fluid handled is extraction water at a temperature of around 70 degrees. The water quality appears clean to the eye. Recently, the motor current has been above normal levels. Upon disassembly, slight corrosion was found on the impeller and the pump casing, with a thin layer of black substance attached to their surfaces. Scraping this off yielded black powder. After removing the black substance from the impeller and pump casing, no further repairs were carried out. Once the pump was reassembled and put into operation, the current was around 28 A; over the course of 2–3 days, this current gradually increased to nearly 40 A, approaching the motor’s rated current. Stopping to clean up before resuming is the same as what was mentioned above. The black powder scraped off is attracted to magnets when it comes near them; analysis shows that this powder is magnetic and adheres to the impeller and housing. As the impeller rotates, it must overcome this magnetic force, which results in an increase in current flow. Has anyone encountered this problem before? Where does the black powder come from?
I remember there was a similar post on the forum; you can give it a search.
Are you from Yantai Wanhua? ? ? As the current increases, the pump needs to consume more energy to perform its function! You can check from this aspect!
This is a corrosion product; if the problem of water acidity isn’t resolved, it will appear again
Adding a magnetic filter at the inlet to absorb impurities in the medium – I’m not sure if this method will work
If the medium is clean and has a low viscosity, semi-open impellers should not be used in the selection process; closed impellers will suffice； Based on the preliminary discussions between your manufacturer and the pump factory, it seems that a semi-open impeller should be chosen when the medium contains particles or has a relatively high viscosity ； If there are ferromagnetic particles, using a magnetic pump is highly discouraged. If a magnetic filter is to be used, it must be cleaned regularly to prevent blockage of the inlet. In the case of viscous media, it is advisable to check whether there are significant fluctuations in operating temperature, as this can reduce the pump’s efficiency and lead to increased shaft power as well as overcurrent in the motor
Let’s consider it from the perspective of current, because excessive current will definitely require more kinetic energy, which leads to a decrease in pump efficiency
http://bbs.hcbbs.com/forum.php?mod=redirect&goto=findpost&ptid=1830504&pid=18885530 Is the black powder resulting from the medium corroding the pipe walls?
Since it’s a water pump, there are issues with the water quality; there are iron particles and impurities in the water
Install a filter screen, clean it regularly, and take water samples for analysis of various components