The starting current of the centrifugal pump is extremely high
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Our factory has a centrifugal pump used to transport pull-out oil (flash bottom pump). As soon as the pump starts but before the outlet is opened, it trips due to excessive current, which is about 10 times higher than normal. The pump rotates smoothly when turned by hand, and the motor operates normally when run separately. May I ask what factors might cause this phenomenon?
Static and dynamic friction occur when the impeller cover is not tightened properly, or when the bearings are not installed correctly. When the pump is shut down, there is no axial force, so the impeller can rotate; but once the pump starts operating, an axial force acts on the impeller in the direction of the inlet, causing the impeller or rotor to move toward the inlet, which leads to friction
Yeah, earlier in order to get the pump running, we kept increasing the protection current and protection time. Now 10 times is way too high, so we didn’t dare to adjust it any further
Is the selection correct? Confirm medium specific gravity, pump shaft power
There shouldn’t be any problem; it’s an old pump. There weren’t such obvious issues when it was used before, but it keeps having problems these past few times
Take it apart to check if there is friction between the impeller and the pump casing. If there are signs of friction and the impeller back cover is not loose, thicken the pump casing seal. If there are no signs of friction, check the bearings.
It is estimated that the pump has been idle for a long time, allowing impurities in the system to enter the pump chamber.
Our company has also encountered such problems; since we have not used the stripping oil used by your company, we do not dare to draw any conclusions! The medium transported by our unit is tar. Due to the high viscosity of this medium, after the liquid portion has been transported, the viscous residue settles and enters the pump, causing the pump to experience excessive current and thus trip! We tried adjusting the current at the inlet; this reduced the viscosity, and it worked in the short term. The most thorough solution is to remove all the viscous substances from this system and clean it thoroughly
If that’s the case, it seems to be a fault with the pump itself