Sirs,

Please I need our people with knowledge on these areas to share their findings and thought below

1. As a young operator in the power sector, I find it Curious during our reliability test run for 14days. and there after that in our PEECC the MCC cooling water motors Breakers block switch trips virtually every 10-15 mins. we constantly jewel Resetting the breakers. if I may use the word and I noticed On the HMI screen, the fan motor now running. This has Been the case. pls what could be the case or solution?

2. In the PEECC battery inverter charger (SAFT POWER SYSTEMS) Cubicle A charges well ie 136v/14.9. and standby charges 135v/1.9A . pls is this working well?

 

1) The current drawn by a motor is directly proportional to the load on the motor. Most of the cooling water fans I've worked on had the ability to adjust the pitch (angle) of the fan blades. If the pitch is excessive then the motor will draw excessive current.

However, you seem to be able to very quickly reset the motor starters, which implies one of two things. Either the overloads are not thermal, or something else is tripping the motor starters. Most of the cooling water fans I've worked on use crude vibration switches to protect the finned tube heat exchanger from damage if one of the fan blades breaks or if the fan becomes unbalanced. This usually trips the motor starter and it can be very quickly reset. Many of these vibration switches used a simple magnet and spring mechanism with a screw to change the tension. They are really rather crude, and most commissioning personnel don't know how to properly adjust them, so the switches can be set to actuate with very little vibration. Usually, there is a process alarm to alert a conscious operator of a high cooling water fan vibration.

So, there's at least two possibilities.

2) A standby battery charger is usually set to a slightly lower voltage, which results in very low current--until the primary battery charger output fails. So, this is to be expected.

 

Thank u very much CSA ...MVP

U have actually explained it all. my apology for late reply due to my internet access problem.

On the MCC cooling water switches, it has been rectified by the chief engineer here after we made the observations to him. What he did was to adjust the voltage amps from 22.5A to 24A now. He said it was a design error from GE drawing which in reality is too low earlier. And after this adjustment I have not noticed any trips anymore.

On the battery charger, that's just satisfies my curiosity.

Thanks

 

Avworhiare,

Thank you for the feedback!