Recent content by neps3

Hi Request information on failure modes of current transformers, Post type, bobbin, resin insulated upto 17.5kV from your experience please. Thanks neps3

Just to add a few things. HS has its long standing history of good use in the industry. The advantage of CS is that on HV motors (ie. 6.6kV) which requires testing every year or periodically, CS has its economical advantage 'cos it can be reused.

Yes, agree with you. The IEEE states for electrical machines. The best practice would be to find the design voltage of cable. I am not sure of the design voltage in the US. Like in the UK, Australia area the design voltage of cable is 600/1000V. The minimum test voltage would be 500V. The...

IEEE Std 43-2000 Table 1 gives the guidelines for DC voltages to be applied during insulation resistance test. Rated voltage of <1000 V the test voltage is 500V DC. There are cases where alternator bearing insulation can be tested at lower voltage at 250V/100VDC and this is by engineering...

Simonbailey Is the voltage drop once only or repeatedly? Does the speed of the engine drops? Any trips? Have you checked the phase connections? What is the load capacity? Give some more details. Check your excitation voltage regulator card. Offline flash a battery across terminals (usually)...

Flashover Quite agree with ScottyUK. Scotty is correct. Have given excerpts from our Consultancy Technical Newsletter on few issues on generators: The phenomenon that is known to vary the rotor vibration as the field current is increased is “thermal sensitivity”. The main driver for this...

Mr.Raghunath Thank you for your valued contribution. Agree with you. Thanks Nath

busbar Thank you. I do not have the said standard. Thank you kindly anyway.

Hi The VT used on a 11kV generator SWBD bus has 11/SQRT3 / 110/SQRT3 // 110/SQRT3. The third winding is an open delta used for neutral displacement relay. Usually generators have 11/SQRT3 / 110/SQRT3 // 110/3. However, a gas turbine set have the 110/sqrt3 for the open delta. What setting does...

ruble3 Would you be able to display the values of combustible gases, acidity & moisture of both tests please. How is the oil colour? Thanks

cuky2000 That was excellent posting and advise cuky.

Thank you Mstrvb19

cuky2000 Yes I have visited the site. The formula talks about lambda in the formula but there is an 'l' there. I have raised this with CDA anyway. DO you have a formula please. I am talking of a single bar uninsulated. Thank you.

Hi Could you please give me the formula for the inductance of a single bus bar of L metres. Bus bar of flat shape. a=width b=height Thank you

Dean Yes ABB has come up with a fusing device for HV that can be added to the switchboard to protect the aparatus from excess fault level. I do not have full details but you can contact your local ABB and they should put forward a proposal. For large generators it is proper for them to...