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Recent content by JohnMcNutt

  1. JohnMcNutt

    Altitude de-rating of Turbocharged standby generator

    It depends mostly on the particular engine. Every proposed genset will have a spec sheet with numbers to calculate with elevation and temperature. The manufacturers tend to use the same prime mover across several kW steps. So if you happen to land on the model/step with the smaller generator...
  2. JohnMcNutt

    Hydrogen fire at Golden Empire Transit demolishes bus, tanks explode ....

    I read that, back in the day (as late as the 1950s), places were still supplying town gas/water gas/coal gas/producer gas/city gas to houses. It was supplanted by NG by the 1960s. Made by quenching some sort of burning carbon solid with water in the absence of air, which made hydrogen, carbon...
  3. JohnMcNutt

    Open Delta 3 Phase Problems

    I wonder if the utility has uneven loading on their system and in the afternoon, their voltage balance between phases gets out of whack. I think that is what you said. Maybe I am a simpleton, but why can't a dust collector be run direct off the line? Eliminate the VFD and all associated...
  4. JohnMcNutt

    3ph 220v to 380v

    The reconnection strap area looks awfully three-phase-ish to me. It is hard to see from either of these photos. But in the reconnection area photo, the upper six terminals appear to be connected as a wye point, with three large neutrals leaving the box. The lower six appear to be the 3 active...
  5. JohnMcNutt

    Ukraine Nuclear Power Plants

    I just came to this discussion to see if any of you with experience could comment on the red forest trench-diggers' irradiation. Is there good intel that this is a true story? What would be the likely source of the radiation that they may have received?
  6. JohnMcNutt

    High Voltage Transmission lines side distances (Rights of Way)

    Not sure how well I would sleep in these houses.
  7. JohnMcNutt

    Sheared Flywheel Bolts on Generator

    Speaking from practical experience, there is no way a pair of XW inverters has enough stiffness to shear any bolts in a 30 kw genset. I suspect a purely mechanical problem.
  8. JohnMcNutt

    Using a small, cheap inverter for single to 3 phase

    I don't know about other brands, but the general advice on here has been to use one from a big name mfr. Hitachi makes single-phase-intended units, and we have one and it has been performing well. https://hitachiacdrive.com/hitachi-nes1-series-ac-drives/
  9. JohnMcNutt

    How much better are voltage optimizers compared to a traditional capacitor bank and PF correction

    Exactly. Jobs have a couple of purposes: to make the company money, but also to expand the prestige and experience of the company. And certainly they must never detract from the prestige of the company.
  10. JohnMcNutt

    How much better are voltage optimizers compared to a traditional capacitor bank and PF correction

    To echo Jraef's story. If I see a project has no technical merit, I decline to be involved in any way. Whether I see there is money involved, or not. There was a customer of ours who also wanted some sort of "filter for dirty POCO power" installed. I respectfully declined. A colleague took...
  11. JohnMcNutt

    Lake Mead Water Level to drop to historic lows

    About 60 years ago, there was a cluster of these new, larger dams being built or enlarged, as well as smaller stream storage. Our family was involved in some of the smaller projects. They knew the the variability of the seasons and they saw the need. It was always conceived as 5+ years of...
  12. JohnMcNutt

    Soft Starter for High Inertia Fan Motor Single Phase 5 HP

    In case I have not made this clear. There is no probability of all loads starting at once. The large fan does not start until controls tell it to start, and air conditioners these days all have variable delay built in. I understand how SCR soft starters chop the waveform. And have some idea...
  13. JohnMcNutt

    Soft Starter for High Inertia Fan Motor Single Phase 5 HP

    I am still interested in expanding on the initial comments on this thread. We have also discovered Stellar makes a whole range of them for the application, but have no experience with the company. They specifically list CS/CR 1ph 230V motors as the application for these starters. What about...
  14. JohnMcNutt

    Soft Starter for High Inertia Fan Motor Single Phase 5 HP

    As it stands, the installation has an old existing 22 kw genset, shunt excited, that will barely start the motor (and I mean just barely) with a maximum of grunting and frequency loss. But it comes up to speed, eventually. (The fan was installed with no consideration for this). The owners are...
  15. JohnMcNutt

    Soft Starter for High Inertia Fan Motor Single Phase 5 HP

    Been looking around for a product that meets specification to soft start a single phase fan motor. 5 HP, 3500 RPM, 230 V, 21A nominal, 60 Hz. Currently started DOL but would like to limit inrush to make it easier on standby generator. Current acceleration time is 2-3 seconds estimated. This...

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