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Recent content by stratford

  1. stratford

    Beariing temperature

    mbensema I measure the temperature with RTD, the motor is greased. Unfortunately i dont have motor catalogue either bearing manufacturer. Can you rpopose trip limit for dip groove ball bearing?
  2. stratford

    Beariing temperature

    Hello to all. On site we have a 6.3kV motor with Drive end bearing D625-6322-C3. On this bearing we experience temperatures to 61 oC. Is this normal wroking temperature? The protection relay of the motor trips at 70 oC. I think this is a little bit more sensitve than usuall. In other...
  3. stratford

    Motor bearing temperatures

    Hello to all. On site we have a 6.3kV motor with Drive end bearing D625-6322-C3. On this bearing we experience temperatures to 61 oC. Is this normal wroking temperature? The protection relay of the motor trips at 70 oC. I think this is a little bit more sensitve than usuall. In other...
  4. stratford

    Cast resin transformers ambient air temperature

    On site we have two cast resin transformers 2MVA running at loads between 50-60% of nominal rating. The air temperature during summer period exceeds the value of 40 oC and sometimes reached 45 oC. The transformers are cooled with natural circulation of air from air holes on the bottom and air...
  5. stratford

    GT 9FA DLNII TK fans issue

    hi rmw and thanks for the answer. We noticed exactly what you say . In winter time TK fans absorb higher amps than in summer time. About the pressure i dont have specific measurement. But we have noticed that the machine hall has underpressure in comparison with the external environment and as a...
  6. stratford

    GT 9FA DLNII TK fans issue

    On site we have a Gas Turbine GE 9FA DLNII. The exhasut frame of thegas turbine is cooled with inlet of air via the TK fans, exhasut frame blowers TK-1 and TK-2. What we have seens until now is the motors working to nominal current, the diverter flap stucking in the middle position. These fans...
  7. stratford

    GE generator Power system stabilizer

    Dear all On site we have one Ge generator 325MVA 4-pole hydrogen cooled with static excitation system EX2100. One of the features of the excitation system is the Power System Stabilizer. Unfortunately this is not tuned yet. Is it possible to tell me some more theoretical or practical data fro...
  8. stratford

    suppliers of voltage sensors

    On site and on our 400kV switchyard we use TRENCH voltage and current transfomers, type VEOS 420. Very reliable at the moment.
  9. stratford

    Gas turbine protection - motoring

    Hi ters. The turbine mechanical parts will start overheating. Also the generator will draw big amount of reactive power. This is the reason that if the generator circut breaker fails then thne Circuit breaker function shoulf trip the overhead breaker, on the grid. Also there should be thrust...
  10. stratford

    Arching rings on 400kV overhead lines

    Hi bacon, thanks for the pic. It seems that the corona rings are towards the insulators strings and not towards the active line as it happens on our site.
  11. stratford

    Arching rings on 400kV overhead lines

    HI Scotty and thanks for the pdf. n our plant the rings are not installed at the Step Up transformer bushing but on the tension insulators. he question is if they rings should be on the live part or upon the tension insulator. From what i read on the NGC pdf they rings should be installaed in...
  12. stratford

    Arching rings on 400kV overhead lines

    Dear all. I want to place my question about the installation of arching rings on 400kV overhead lines. These rings are supposed to carry any transient overvoltage and try to break the air gap so they should be placed in the lower length between the live terminal and the earth. Can you give some...
  13. stratford

    Gt generator neutral grounding

    subtech The generator nominal apparent power is 324MVA and the power used to start the generator is maximum 11MVA. rraghunath Thanks once again for the detailed justification.
  14. stratford

    Gt generator neutral grounding

    The gas turbine is a GE 9FA DLN II with a generator coupled and the GT is started not by a prime mover (another generator) but as a motor supplied with variable frequency and voltage through a frequency converter (GE LCI).
  15. stratford

    Gt generator neutral grounding

    rraghunath The generator is grounded with 25kVA 12kV/120V transformer whose secondary is in parallel with 0,525 Ohm/350A resistance.

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