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  1. TomG33

    implied service factor - ca 1972

    The implied service factor would be 1.0 unless otherwise stated. Tom
  2. TomG33

    Drives at motor's starting up

    There are many parameters that need to be set to match a drive with a motor, and application. Some of the primary type parameters you are looking at are things such as Supply Volts Supply Frequency Supply isolation Transformer size. Control power voltage level Motor volts Motor Frequency...
  3. TomG33

    Line Shaft Drive for Paper Machine

    astroid, I agree with Gunnar that condensate in a dryer can load the drive up but I think there is something else at play as well here. You have to watch the speed rating of your motors. THe nameplate data tells you the various conditions that must be met for the motor to deliver it's rated...
  4. TomG33

    Converting to GE-Fanuc PAC Controllers

    Tomatge, I have just done a migration from 90-30 to RX3I and as dV8r says it is quite easy, THe only pitfall I found was that some of the timers used in the 90-30 are a little different in the RX3i, I had to check them individually. This may not be relivant in your system. THe other thing is...
  5. TomG33

    Gearbox for water turbine

    Feg, Forgive me if I am stating the obvious, but the first thing is to match your speed characteristics of the two machines. As far as I am aware there are two basic designs of water turbine, The pelton Wheel, which is disk with scoops at regular intervals around it's circumference. A jet of...
  6. TomG33

    LCI problem

    Hey Oftenlost, Maybe you have fixed this by now, Just saw the post today. But anyway i have a few questions/comments to put up. I guess there can be two reasons for a line to line flash in the motor, 1 = too many volts 2 = Too little resistance. Given the description you supplied I do...
  7. TomG33

    DC drives for shunt AND series field motors?

    You should be able to find manuals for most GE Drives. What is the type DC2000 or silcomatic, or whatever. Supply some detalis and I will give you a link, Tom G
  8. TomG33

    If DC generator excited by AC

    Harry641, We need a little more information on the rating of your motor. 1000 Volts supply is this the rating of the motor, or is it higher or lower? 250 Amps. Where is this with respect to the motor rating ? If you have the motor commutator sparking and this test point is within the normal...
  9. TomG33

    phase sequence test of medium voltage sources

    Salor55. The sequence only has to be verified once. Usually after you do this, the wiring is not disturbed, so you can be confident that for future times all will be well. We have many machines, with Synchronous motors, that we run up to synchronous speed and then actively synchronize with the...
  10. TomG33

    Winding Temperature Stabilization

    I agree, Rotman. In reality, You ave not changed the motor, Just it's load. Renameplating the motor should be done only if the motor is physically changed to operate differently. All you will have done is to change the load, and verified that it is operating within the design limitations of...
  11. TomG33

    Winding Temperature Stabilization

    THe answer to your question lies in the motor name plate data. It says the insulation class is "F" and it inferrs that the motor is designed for a class "B" rise, meaning that the motor is designed for insulation class B operation. What this means is that the motor is designed to limit the...
  12. TomG33

    Power calculation from torque

    This looked really goood for a while, until I realized that the adjustable load of the trainer will take care of all these differences, So it is back to the power measurement variation :o) Tom
  13. TomG33

    Power calculation from torque

    I have been following this discussion with interest over the last day or so and spending some time pondering over just what is the real issue here. From Bruce's initial statement and in his follow up posts it seems that the athelete can produce more power on the road as opposed to what he can...
  14. TomG33

    Starting Current wth Soft Starter

    Hey guys, again Like a few others I have leapt into this a little late, But I want to point out to itsmoked something he missed in his post containing the Waveforms and included comments about the non zero Voltage switching. With SCR's the switching is done at zero current, not zero Voltage...
  15. TomG33

    Bucyrus 3270 Dragline

    "Is there a 3270 model (w/o the 'W' which I guess is for the walking mode of motion)?" The simple answer is No. You are correct, the "w" designates a walking dragline. the other option is Crawler mounted however they are only used on the smaller ones.I am not sure what suffix they write for...
  16. TomG33

    VFD on a Synchronous Motor

    Zoobie, a question about the application first. how has the need for the variable speed drive come about. Do you need to run the Compressor at different speeds to suit the Process, or are you looking for some type of "Soft Start"? As mentioned by swgrmfg the LCI is probably the best way to...
  17. TomG33

    DC Motor issue

    The motors are not identical, sure enough, But i am surprised that the controller is is going clear out to >6000 Amps and then tripping on Overcurrent. it almost seems that the controller is loosing control of the current. From my Experience, this sort of current runaway is purely a function of...
  18. TomG33

    DC Motor Derating

    Edison, Another thing you could consider is Second hand GE MD for Mill duty Motors,. These are nameplated at 475 Volts, however designed to run at up to 600 Volts. a better match for your 550 Volts. The MD820 is rated at 800 Hp amd 800RPM at 475 Volts (926HP and 926 RPM at 550 Volts) Rated...
  19. TomG33

    DC Motor Derating

    Edison If they are USD then i would say it is a reasonable buy. but the Extra 46 for the class 1 overhaul, seems a little high. I would shop around first before committing to the overhaul. Tom
  20. TomG33

    DC Motor Derating

    Edison123, A cyclic load such as this changes everything. If your duty Cycle is only 30% load, (backed up by the low winding temp rise) then the 2,000 Hp Motor should be able to live with this even with the field weakened below name plate. We do our RMS Calculations over a 5 minute period, So...

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