Problems with centrifugal pump commissioning?
Thread Content
This post was last edited by zhaohh3211 on 2010-9-16 at 11:14. I would like to ask the experts: I have a newly installed centrifugal pump, and I am about to start testing it. How long should the motor run without a load, and how long is appropriate for operation under load? What issues should be taken into consideration during the trial run?
Generally, the coupling is disassembled and run idle for 2 hours; as long as the temperature does not exceed the limit, it is acceptable. Make sure the motor rotation direction meets the process requirements. Infrared thermometers can be used for temperature measurement.
Keep good records of things such as shaft temperature, current, and heating rate; having these original records makes it easier to make comparisons in case of future failures!
First, disconnect the coupling between the motor and the pump, and run the motor without a load. Pay attention to the motor’s temperature rise, rotation direction, and no-load current, etc. Running it for about 2 hours is sufficient. After connecting the couplings, it is also possible to run the system without a load for a period of time, depending on the process requirements; the aim is mainly to determine the difference between the no-load current at this time and the no-load current of the motor when tested individually. As for the testing period, it doesn’t matter how long the operation under load lasts; what’s important is the requirements of the manufacturing process, as it is at this stage that the process needs to collect certain data.
This post was last edited by zhaohh3211 on 2010-9-16 at 11:15. After running idle for 2 hours, in addition to the above, it is recommended to use a listening rod to check the operation of the bearings, in order to determine their lubrication status as well as whether the inner and outer rings are moving improperly.
Operation under load: the petrochemical industry generally requires 4 hours.
Reply to 4# zyz8438: The duration of the trial run isn’t determined by the process specifications, right? The petrochemical industry requires at least four hours.
Let’s see whether it’s a high-voltage motor or a low-voltage one; our 700kv motors operate for 8 hours!
Trial operation and no-load testing of the motor are two different concepts!
The motor and the crusher can be operated separately for two hours; the main things to monitor include current balance, motor temperature, as well as the vibration and noise levels of the motor. When the pump is connected and operated under load, the above parameters still need to be considered.
Run it without a load for 2 hours, then check the temperature of the motor bearings as well as the temperature rise of the coils (in practice, this is measured on the motor housing itself). As for operation under load, testing is usually carried out during water circulation; it’s sufficient to check the current levels, and it doesn’t take long either – the amount of water in the system is limited, so continuous circulation isn’t possible