Pump barring issue
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For our new equipment, the pumps have already been tested. Recently I was maintaining the pump on my unit, and after it rotated a few dozen degrees, it would turn back again as soon as I stopped applying force to it. I’m not sure whether this is due to improper alignment or if it’s normal behavior.
It’s best to release the grip after turning the disc more than 180 degrees; try turning it in that direction. If it keeps turning further, it’s a problem with static imbalance； If it returns to its original state, there might be issues such as the seizure of the mechanical seal friction ring; it’s advisable to disassemble it and check. Generally speaking, it’s unlikely to be a problem with alignment.
There must be a problem with the static balance of the impeller.
It is also possible that the pump outlet is closed; after the pump is rotated, the liquid inside it gets compressed, and it will rotate again once the outlet is released (this is common in reciprocating pumps)
What was said on the 4th floor is possible, but as the original poster mentioned, it turns back right away once you let go – that’s really not common
I’m also quite puzzled; I wonder what type of pump the original poster has? Reciprocating or centrifugal?
It should be the motor that drives it to turn back; this will happen even when the motor is running idle. There’s no need to explain it further – anyone who understands the principles of motors knows this.
We have seen this situation on centrifuges, and it was ultimately determined to be static imbalance.
There are several possibilities: 1. There is a problem with the bearing； 2. Impeller eccentricity ； 3. There is sticking.
This situation is relatively rare in centrifugal pumps. Possible causes include: 1. Something is stuck inside the impeller, causing it to become unbalanced; 2. The stationary and rotating rings of the mechanical seal stick together, and under the influence of the spring in those rings, it might help to rotate the pump a few more times
Spin it several more times; if it keeps slipping every time, the rotor is unbalanced.
Could it be that the bearing is slightly misaligned, which causes rotation when the disk is turned?
It’s not clear whether it’s horizontal or vertical; there’s definitely a problem with the rotation of the pump. You can start the pump to see what’s going on!