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Recent content by genhead

  1. genhead

    Upgrading Utility Distribution Transformer with an NGR

    I knew that to be so with resistors. I understand that line-to-ground loads/faults will cause rising line-to-ground voltages on the unloaded/faulted phases. Is the effect any different with a reactor as opposed to a resistor?
  2. genhead

    Upgrading Utility Distribution Transformer with an NGR

    Rockman7892 asked - Does a neutral grounding reactor still allow the connection of L-N loads in contrast with a grounding resistor? Does anybody have any comments?
  3. genhead

    Lightning Protection

    Thanks all for the responses. The client has requested that we fit them so we will, but with a disclaimer that clears us of any liability for their effectiveness (or lack of).
  4. genhead

    Lightning Protection

    Hello all, I have attached details of a lightning protection device that a customer has asked us to fit to some mobile equipment which has a steel mast. The equipment is on rubber tyres and there is no grounding conductor. 1. How does it work? 2. Does it work? Thanks
  5. genhead

    Edmonton condo evacuation

    Were they tempting fete when they named the building?
  6. genhead

    Diesel Genset Engine - Torque Speed Curve

    Here is the data sheet from a small Kubota engine that we use in the application you are describing. If you can get the Iveco engine model number (which, curiously, isn't mentioned in your Generac spec sheet) then you should be able to find the data sheet. There's probably enough engine...
  7. genhead

    Diesel Genset Engine - Torque Speed Curve

    Why? The engine will always run at (or close to) 1800 RPM. But if you really want the information, the engine manufacturer IVECO should have it.
  8. genhead

    Low PF on 3ph generator

    I can't see exactly what model controller you have there but typically the "maintenance alarm" is triggered when a certain amount of running hours are reached, or sometimes a number of calendar days. Some manufacturers set the alarm as a shutdown meaning that the generator cannot be operated...
  9. genhead

    Steam rocket designed by self-trained man crashes due to premature parachute deployment.

    From Wikipedia, "Accidental self-sterilization also qualifies; however, the site notes: "Of necessity, the award is usually bestowed posthumously." The candidate is disqualified, though, if "innocent bystanders", who might have contributed positively to the gene pool, are killed in the process...
  10. genhead

    Generator Sizing for VFD Driven Motor up to 250HP

    Waross, There are two separate issues. One is the effect that the distorted waveform has on the AVR, sometimes causing poor voltage regulation. Does anybody have any suggestions for suitable AVR sensing filters? The other is the THD-V which results from the THD-I created by the drive. The...
  11. genhead

    Generator Sizing for VFD Driven Motor up to 250HP

    I realise that you are only intending to run the drive and no other electrical load from this generator but that leads me to some other questions which maybe jraef or others could answer. As well as the extra current, the 30-35% THD-I is going to result in significant THD-V. For a typical...
  12. genhead

    Typical Subtransient Reactance for Smaller Synchronous Generators?

    Very small machines can vary significantly. I have just been looking at three machines from different suppliers, all in the 130-140 kva range. The X" values are 6.9%, 8.3% and 12%.
  13. genhead

    PMG retrofit to Stamford alternator

    What is the model number of the generator?
  14. genhead

    Battery charger

    I've come across several "fancy" multi-stage chargers which work fine as long as only the batteries are connected. If there is any standing load at all (controller, PLC etc) then the charger stays in boost mode forever.
  15. genhead

    Power factor of diesel generator for a purely resistive load bank

    The load bank will have a cooling fan driven by a motor running at around 0.8 lagging power factor. As the resistive load increases so the total power factor increases towards 1.0. At lower loads the inductive fan load is relatively more significant.

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