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  • Users: pumpo
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  1. pumpo

    start condition

    If we are starting a centrifigul pump at 50% discharge will that affect the start power conditions?
  2. pumpo

    severe voltage drop

    One more question i was told that if our start time for motor to reach Rpm is increased by 36% that that will be proportionaly correct to the Vd. That sounds a little too simple for me.
  3. pumpo

    calculate voltage

    The load bank was setup to pre load the gen set so that when we switch the load over to the pump the generator would already be off idle and help to reduce Vd from 36% or at least that was tge idea from our Test engineers. I was tols that that is a start only equation and if our system was...
  4. pumpo

    severe voltage drop

    What software would you guys recomend??
  5. pumpo

    calculate voltage

    One more thing if you could. If I collect the information nessecary whatare the calcs necessary to achive an accurate #, is there a site you would recomend or a book title out there that would assit me. If these tpes of situations come up again. or just something that will give me a good feel...
  6. pumpo

    calculate voltage

    We tried to run a resistive load bank on the pump and it made a less than 1% diffrence @ 500Kw pre-load. A local electrical engineer told us that on a setup with two 2Mw gensets starting a 6600V 1100Kw motor with the same load bank would give a 28% Vd. So I assumed that we should see at leat...
  7. pumpo

    severe voltage drop

    We are starting DOL. in this case. The start current fro this motor is estimated and not tested. we calculate this value from the Irms Vrms. so the start current is actually unknown at initial testing of the pump. I have been given this equation for motor start conditions Astart/Ameasured =...
  8. pumpo

    calculate voltage

    Sorry I forgot to list the motor V 2300 is the V rating of the motor. At 500Kw the I rms should be 216 approx. is there any refrences or Recomended books that i can use to bone up on this. I am a computer guy who was asked to look into this and could use all the help I can get. Thank you to all...
  9. pumpo

    calculate voltage

    the generator is a 2Mw at 460V so it should be at 4347Amperes. corretct??, the Transformer is a step-up 4-1 the generators or generator in this case are matched to the transformer for the correct high side volatge. the software says that we are pulling 564Irms and 1494Vrms. But we are...
  10. pumpo

    start voltage current relationship

    could you help me with another query? The software that we use calculates the start current from the Irms, Irms/Vrms X Vrated = Istart is that also correct if we have a correct voltage. The motor start I is estimated by the manufacturer because they do not manufacture or assemble the whole...
  11. pumpo

    severe voltage drop

    The gen is soley for the purpose of starting and running the pump nothing else is online with the pump. that is why it seems so high.
  12. pumpo

    calculate voltage

    The problem is the motors are unrated.since the rotor and stator are the only two items produced by the manufacturer all else is made in Japan by Parent company, they only supply an estimated start current, thus we need to measure or calculate those numbers. currently we are using an outdate DA...
  13. pumpo

    calculate voltage

    the start current is for the customer, we manufacture and test large cryogenic pumps. and the customer wants every piece of data available.
  14. pumpo

    calculate voltage

    We are using an outdated DA program to record test data. our system calculates start current from the rms measured by a few yokagawa's. the start current is calculated Irms/Vrms X Vrated= Istart to really mess things up upon motor start we are seeing a 36% Vdrop A 500Kw motor being powered By a...
  15. pumpo

    start voltage current relationship

    Start voltage / amprage relation ship was given to me by one of our engineers as Arated/Ameasured = Vrated/Vmeasured so that if you see a V drop at the motor you will also see a decrease in Ampreres. Is this correct????
  16. pumpo

    severe voltage drop

    We are experiencing a severe voltage drop at motor start. The motor 500Kw 3ph 2pole. 2300V rated. Generator, cummins 2Mw set to 460 approx, 4-1 transformer, resistive load bank between gen/trans. we get 36%Vd at motor start. estimated start current is fine it is at or just above estimated value...

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