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  1. EngSnow

    Add fans to transformer

    Thanks guys. The FA rating is 1333 KVA, but as David beach said, this only true when we use vendor provided fans. My question is, if we know know the difference in temperature those fans provided, can we calculate the new rating? For example, if we able to lower the temp by 20 degree C, how much...
  2. EngSnow

    Add fans to transformer

    We have a 480-208/120v, 1000/1333 KVA transformer with load running close to its OA rating. We decided to install custom made fans, such that air is forced to go through windings. I know this might not equal it's FA rating, but how can we calculate new rating? we can measure all peremeters...
  3. EngSnow

    Sag Protection

    Thanks guys I just checked out the GE site. Also, checked out Piller...just learned they bought Active Power...which I'm familiar with. ScottyUK, this is only for Sag Protection.
  4. EngSnow

    Sag Protection

    Thanks jraef. We actually have a number of those on site...they work really good. Only thing, they protect against 0% sags for a maximum of 12 cycles. I wanted to see if anyone has any experience with other technologies like flywheel. They claim 14 sec protection, but not sure about maintaining...
  5. EngSnow

    Sag Protection

    Anyone knows a good industrial brand for Sag Protection, using energy storage devices such as capacitors, flywheel, or battery for > 1000KVA applications?
  6. EngSnow

    Tray continuous ground conductor

    7anoter4, thanks for your reply. I still do not see the cable tray connection to grounding conductor requirement. This section you refer to (250.86) is for enclosures and raceways (conduits), not cable tray.
  7. EngSnow

    Tray continuous ground conductor

    Per 250.96(A): " Cable trays.....that are to serve as equipment grounding conductors...". The cable tray in question is NOT to serve as equipment grounding conductor. Is there any other reference in the code that addresses this issue?
  8. EngSnow

    Tray continuous ground conductor

    Our contractor installed a multiconductor cable in a tray. I was told per NEC, we have to increase size of existing bare tray grounding cable because it's smaller than our newly installed cable equipment ground. Is that correct? Each cable in this tray has its own equipment ground.

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