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  • Users: DRWeig
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  1. DRWeig

    Reallly long panel feeder -- how to connect to panel and feeder breaker?

    Hi Fellows, I'm working a project involving great distances from a main switchboard or power panel to some 250A 480/3 panels. The champion is an 850-foot run. In order to keep voltage drop to less than 3 percent, I calculated the need for 4 sets of 350 MCM per phase at an 80 percent load on the...
  2. DRWeig

    Simple Linear Regression with Weights

    Group, Does one of you perhaps have a VBA routine for linear regression with weighting, without using any built-in Excel functions or plug-ins (boss request). I've attached a very simple example of data. My program is much more complex, but I've never dealt with weighted regressions before...
  3. DRWeig

    Tiny motor needs lower voltages for lower speeds

    Guys and gals, Original control of a two-speed motor (1/20th HP) was from a transformer with 120V primary and a double-tapped secondary at 85V (for high speed) and 75V (for low speed). Transformer is no longer available, what would be the downside of using resistors to drop the voltage...
  4. DRWeig

    Help a Newbie with Worksheet.Application Functions in VBA?

    Hi Group, I have a monster VBA program written, and for the first time ever I want to use a worksheet function (LinEst). I've searched the world, but I can't find the answer to "Run Time Error 424 - Object Required" that I get. A simple example is attached. Can anyone take the time to point me...
  5. DRWeig

    Pressure Drop Across Chiller Tube Bundles

    Hi Measurement/Control folks. I'd appreciate any input you have to this thread in the HVAC/R forum: http://www.eng-tips.com/viewthread.cfm?qid=408423 Thanks much! Best to you, Goober Dave Haven't see the forum policies? Do so now: Forum Policies
  6. DRWeig

    Differential Pressure Across Chiller Barrels

    Hi Team, Under near-laboratory conditions and with very accurate instruments, I'm measuring flow through both chilled and condenser water barrels of a chiller. Instead of the expected flow-squared correlation to pressure drop, I'm getting flow to the 1.7 or 1.8 power. Anyone here ever run into...
  7. DRWeig

    Quality Control Software?

    Hi Guys, We run a UL 508a panel shop, and we have a manual checklist for QC. It's quite extensive, but we're looking into automating quality control. Has anyone in a similar shop implemented an automated QC software program? If so, would you share your experience? If no, please give me an...
  8. DRWeig

    Chiller Breaker Settings

    Friends, I've walked up on a chiller with the following settings on its breaker: Instantaneous pickup 6400A Short-time pickup 4800A Short time 0.3s Earth pickup 640A Earth time 0.3s Here's the chiller data. Note it's a Y-Delta starter. Motor LRA= 2616 A Primary RLA = 473 A Min circuit...
  9. DRWeig

    Insert picture without box around it?

    I haven't found the magic answer -- if I insert a reference picture (.png), DraftSight draws a box around it that I can't seem to get rid of. Any ideas? Best to you, Goober Dave Haven't see the forum policies? Do so now: Forum Policies
  10. DRWeig

    Boost Transformer Breaker

    Hi Group, I'm confused on this one for some reason. See attached diagram, I'm boosting 208V to 240V to feed a 31 FLA motor. The size I calculate for the boost transformer is 2 kVA, so its full load input current is 8.3A. But the motor needs a 50A breaker. According to NEC 450.4, though, I...
  11. DRWeig

    Can't install DraftSight - Windows Installer Error 1271

    This happened when updating, and no amount of my Windows kung-fu has been able to get around it. Has anyone here experienced this and fixed it? [pc] Best to you, Goober Dave Haven't see the forum policies? Do so now: Forum Policies
  12. DRWeig

    PE Required for Energy Audit in Your State?

    For the US folks: Is a PE license required in your state for building energy audit work? Best to you, Goober Dave Haven't see the forum policies? Do so now: Forum Policies
  13. DRWeig

    NO2 Sensor Placement in Fire House

    Hi group, Not exactly a thermo problem, but I haven't gotten any responses in the other forum I tried. The situation is a fire truck with its engine running in its bay in the fire station. The client would like a sensor with alarming on high NO2 level (2 ppm) in case of exhaust leakage. When...
  14. DRWeig

    UL508a Panel / Translate to EU and UK

    Hi group, I need a kick-start, don't know where to look first. We're a US UL508a panel shop, meaning we can assemble various industrial control panels to the UL standard and apply a UL label. A long-time customer wants us to build some panels for installation in the UK and EU with UK coming...
  15. DRWeig

    Inspect and Test Smoke/Fire Dampers How Often?

    Hi all, I got myself lost here... Is there a code or standard that dictates inspect/test for smoke and fire dampers? How often would that be? I'm unable to get to the NFPA codes online today or I'd have given it a shot already. Thanks! Best to you, Goober Dave Haven't see the forum...
  16. DRWeig

    The Almost-Modes

    Hi all, I'm scratching my head on this one. I have a column of numbers (30,000+). I can easliy find what number occurs more often than any other with the =MODE(x:y) formula. What I'd like to know are the numbers that occur second most, third most, etc... Any quick way to do this without...
  17. DRWeig

    Welding Smoke and Sacramental Incense

    I've had this posed to me half a dozen times in the past two months. "Need a sensor to sense welding smoke to activate / deactivate exhaust fans" "Need a sensor to sense incense smoke to activate / deactivate exhaust fans" These things generally happen in large-volume rooms like an auto shop...
  18. DRWeig

    Field Assembled Capillary thru Conduit Seal (Hazardous Locations)

    OK, Hazardous Engineers: I'm looking for documentation that says it's OK to pass the capillary tube in a bulb-n-capillary temperature switch when assembling in the field. Of course, the switch itself is in an explosionproof enclosure. I know it's OK to seal a capillary entering a box, because...
  19. DRWeig

    Smoke Control Panel without UL or any other NRTL listing?

    A UL 508a panel shop has been assigned to build a smoke control panel. They can't stick a 508a UL label on it, that is prohibited. UL 864, category code UUKL is what applies to smoke control panels. No panel shop can do UL 864 stuff, that is a standard that must be certified by submitting...
  20. DRWeig

    ABB FeederAll

    My Google kung-fu and the ABB web site have failed me. My local utility has a motor starting study done in FeederAll, and they are willing to share the project file with me. The problem is that I don't have FeederAll and cannot for the life of me find how to purchase / download / access the...

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