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  1. edison123

    To replace faulty power alternator with a smaller unit

    https://tgadvisers.com/steam-turbine-and-generator-reduced-minimum-load-considerations/ If you got 20k, have at it. https://www.epri.com/research/products/000000003002013589
  2. edison123

    Generator with low IR

    Phase to phase IR? Is it 6 leads generator? If not, you should be getting zero megohms between phases.
  3. edison123

    To replace faulty power alternator with a smaller unit

    Under powered steam turbine will have water condensation, scaling of blades leading to lower life.
  4. edison123

    Hoists attached to another hoist to rotate load

    I rotate large electric machines up to 20 tons in our shop. I use two 20 ton hoists mounted independently in the same cross travel bridge.
  5. edison123

    Power Needed to Rotate a Mass to a Speed in a Specified Time

    Greg - 5 to 10 minutes is my plan. It's a time vs KW decision. MintJulep - Ok.
  6. edison123

    KW, KVA, KVAR relationship

    "If I reduce the KVA that should equate to a reduction in amps, correct?" Correct. "if there is an amp reduction, shouldn't I be able to calculate an efficiency increase?" The reduced current means less I^2R loss in the generator, cables, transformer, which is indeed a power saving. You need...
  7. edison123

    Power Needed to Rotate a Mass to a Speed in a Specified Time

    I am looking at 3300/600 = 5.5 rpm per sec. That's linear acceleration, right?
  8. edison123

    power factor issue

    govt department advised correctly. 24x7 capacitor with no other inductive load will drop your pf like a stone.
  9. edison123

    Power Needed to Rotate a Mass to a Speed in a Specified Time

    Littleinch Yes, if the acceleration time is increased from 5 to 10 minutes for 0 to 3300 RPM, the power required drops to half i.e. 14.34 KW. I am looking at a linear acceleration which the VFD will be programmed to do. Both the drive cage induction motor and VFD are rated for 132 KW. I...
  10. edison123

    Power Needed to Rotate a Mass to a Speed in a Specified Time

    Thanks guys. But when the load is running at 3300 RPM, the motor has to deliver that peak power of 28.68 KW, right?
  11. edison123

    Power Needed to Rotate a Mass to a Speed in a Specified Time

    Driving motor has enough power and speed range up to 3300 RPM and the whole set up is via a big VFD.
  12. edison123

    Power Needed to Rotate a Mass to a Speed in a Specified Time

    Thanks, Greg. I did do some math (had to recall some college days equations) and got exactly double of that i.e. 28.68 KW. Wonder where I am going wrong. Got moment inertia I = 72 kg-sq m right Torque = Moment of inertia x Angular acceleration = 82.97 N-m Power = torque x angular speed =...
  13. edison123

    Power Needed to Rotate a Mass to a Speed in a Specified Time

    What will be the power needed to rotate a uniform cylindrical rotor weighing 1600 kgs dia 600 mm speed 3300 RPM 5 minutes acceleration time from zero speed to 3300 RPM Any particular equation to calculate this? Will acceleration time play a role in power needed? The cylindrical rotor will be...
  14. edison123

    Small dc brushed electrical motor format "280"?

    In a given motor frame size, 2 to 4 speeds can be designed with corresponding power rating. You need to look for the same frame with the same speed and HP that you want. No standards will specify the power and speed ratings for frame sizes.
  15. edison123

    Electrical motor with rotor issue

    Is that a stator - rotor rub? Aluminum die-cast rotor? Speed?
  16. edison123

    Electrical motor with rotor issue

    "We are bit sure that the problem is in rotor laminations because a similar motor with the same symposium was deconstructed and found a deformation in it’s lamination." What kind of deformation? Post some pictures and complete motor nameplate.
  17. edison123

    1000volt deep well motors

    "The VFD acts as the filter". How? why not go for a 690 V motor of same size? standard VFD and reduced cable size.
  18. edison123

    How to use the Variac

    Looks like the top mcb is the output with output voltmeter connected. The connector terminal blocks seem to be unfit for load output. Zero nameplate details. OP has to engage to more
  19. edison123

    GCB in the 15,000 Amp range

    Great info, Gianoli. 33,500 A ? :oops:
  20. edison123

    GCB in the 15,000 Amp range

    Who is making 15,000 amps breakers? The maximum I am aware of is 5,000 amps VCB. Large generators have the breakers on the HV side of the generator step-up transformers.

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