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Recent content by waross

  1. waross

    Motor control via VFD using V/F ratio in Squared mode

    First, it is only the very best engineers in a firm who design and program the Pulse Width Modulation programs. Still there is a place for everyone. Less capable engineers often end up in sales, with some of them writing descriptive brochures. In a VFD, the Drive controls the frequency (Hz) and...
  2. waross

    Motor control via VFD using V/F ratio in Squared mode

    By way of explanation, dvd; Is there some way to correlate the mechanical (HP = T x RPM/63025) with electrical (HP = 1.732 x amps x volts x power factor x etc /746 watts/HP)? Is the torque/amperage constant in this discussion? Power has to equal power. I don't see the OP using T in his original...
  3. waross

    Motor control via VFD using V/F ratio in Squared mode

    There is a quirk in understanding that I get a laugh out of. 1. Every electrical engineer knows that the neutral in a single phase circuit carries the unbalanced current. 2. Every engineer knows that the phase angle of the load current changes when the power factor is less than unity. 3. Very...
  4. waross

    Sizing Generator- Florida Nursery

    Have you checked the price of diesel fuel per kiloWatt hour at local rates? You may be lucky but diesel power is seldom cheap power. For your situation I would start from scratch and do a survey of all buildings and services. Then I would evaluate each building load. Some buildings may not draw...
  5. waross

    Motor control via VFD using V/F ratio in Squared mode

    Sorry. I was overreacting. There has been a rash of "out of expertise" postings in some electrical fora.I complained in one forum and was put firmly in my place by an "out of expertise" poster. There was a time when a post such as that would result in the poster being banned from the site.
  6. waross

    Motor control via VFD using V/F ratio in Squared mode

    The moderator label is a false flag operation by the new management. The only thing I have here is a false label. I am not a moderator in this forum. I was a moderator in one and only one forum. For years I was never identified as a moderator of that forum. Then I was not a moderator. Then I was...
  7. waross

    Sizing Generator- Florida Nursery

    You missed 127 Volts. I a couple of years servicing lobster boats I saw more strange voltages than I did in 40 years of onshore work. 460, 230 and 115 are not obsolete voltages. They are standard motor voltage ratings. I guess they don't use high leg delta systems on boats. High leg delta...
  8. waross

    Sizing Generator- Florida Nursery

    Sorry. I don't have the energy to take you through basic load profiles to advanced gen-set sizing. What you may think is 240 Volts is usually 208 Volts. 1. This can lead to a 15% difference in KVA loading. 110 Volts has been an obsolete standard for over 60 years. If this is wild leg delta...
  9. waross

    Sizing Generator- Florida Nursery

    A Qualified yes. Technically, yes, but you are pushing the envelope here. The first challenge is the transfer switch(es). The second challenge is voltage drop. These challenges are solvable. If you follow my posts you will know that I very seldom ask for a One Line Diagram. this is an...
  10. waross

    Motor control via VFD using V/F ratio in Squared mode

    Wow. Another poster out of his area of expertise. Followed by another poster out of his area of expertise, adding to the confusion. Oh my. Is there even one way in a thousand to resolve this impasse?
  11. waross

    Speed controllers / Load sharing controllers

    An example; At 80% load on the producing sets, add another set. At 70% load on the producing sets, drop off a set. In the real world, check the capacities to avoid short cycling. The % values I used were WAGs.
  12. waross

    Speed controllers / Load sharing controllers

    We ran 5 diesel sets, (3 identical and two smaller sets) for years without a controller. All in droop. Operators checked the load every 15 minutes and added or removed sets from on-line as needed. The basic is a controller that monitors the load and starts and stops sets as needed.
  13. waross

    IEC world - GCB in Medium Voltage Switchgear, surge capacitors & lightning arresters placement

    Good practice is to place the protection as close as possible to the protected equipment. You want as much cable length as possible to dissipate the surge energy. If you are protecting against possible lightning surges, then good practice in running the cabling to the arrestor may rule out some...
  14. waross

    Motor control via VFD using V/F ratio in Squared mode

    you must express V as a PU value of rated V. Generally less than one. The actual current and the actual losses depend on the load. All the calculations in the world will not change the mechanical load.
  15. waross

    To install black start generator for 2 power generators 45 MW

    Unmatched units.
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