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Hi For 750MVA generator with casing pressure of 4Bar and load at 650MW generators cold gas temperaures are normally around 38 to 40 deg.cel and hot gas between 67 to 70deg.cel, this figures are my operational experiences, might differ from plant to plant. Cooler inlet gas temp alarm is set at...

Dear all, Manufactures of MV motors recommend 70% to 85% of Un (norminal voltage) for undervoltage protection.What factors were considered when determining the undervoltage protection setting and is there any calculation that can be done from first principles to determine such setting value...

Hi all, Our power plant was initially designed for base load operation but due to some reason we were then required to change operating regime to two shifting (cyclic operation). This meant increased barring hours, increased number of stop starts which had bad impact to our rotors and all rotor...

Perhaps its a good idea to find out why the unit was decommissioned, however you mentioned that you do not have historical data! Not bad idea to start new maintanance file: Option 1: Remove rotor and do proper visual inspection on the stator core and the rotor as well, To see if there's evidence...

Hi A question below: 1. what are the advantages of operating stator water chemisty at low oxyen elevated PH. I recently experienced high copper from the water, oxygen, ph, conductivity levels all ok. iron slightly out. 2. what is the safest dew point when operating h2-water cooled machine? is...

Hi all, I have a question regading 700MW generator rotor. 1. What kind of damage will the generator experience during switch on to stand still (SOS). I have seen pictures of rotor which suffered SOS but not sure exactly what else could go wrong? 2. If say 3000 rpm rotor is turning at lower...

Hi all, I have had a quite number of incidents were the rotor pole A to pole B connector flexible were found cracking progressively due to stop-start operation. I have reaseached quite number of on-line tests and off-line test that can detect this problem. Thus far the stray flux test is the...

Thanks guys for the respons, ScottyUK for the info, please do not forget to send me the info when you back to the office.

Hi What is the impact of conducting MVAr capability test on the generator to prove the the ability of MVAr expoting to the system against the OEM supplied capability diagram. I will push the machine to the rated MVar and keep it constant for about three hours during that time verything must be...

Hi Can someone please explain what effect will barring have on the rotor of 600 to 800 MW machine, will increasing or reducing the barring speed reduce the probability of fretting on the rotor slots etc?. With a two shifting station alot of our machines sees a lot of stop-start mode of...

h2 is the good removal of heat due to losses, it is also to keep h2 purity to accepatable levels. h2 purity of less than 90% contribute or increase losses by 10%. So at higher pressures h2 performs removes heat efficiently.

Hi, Please questions below: 1. I am responsible for the performance, maintanace and condition monitoring of six 600 to 700MW generators.I have since observed that at higher MW and MVar the stator core temps are increasing proportionally but some other sections on the core, particularly the end...

Ya I agree, it is important to atleast have some finger print that you can base your mainatance and life of the insulation on before, this should form part of the commissioning requirements.Its easy and it does not take time to perform the test, i think that engineer is way out of line and will...