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Type: Posts; User: Jraef

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  1. Replies
    27$$
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    512

    When in doubt, I start with Article 100. ...

    When in doubt, I start with Article 100.



    To my mind, the "not normally" aspect of an EMERGENCY eyewash station makes this a dry location. If it's a dry location, all rules for dry locations...
  2. The DRIVE has an encoder INPUT option. That means...

    The DRIVE has an encoder INPUT option. That means it has the ability to accept a signal from an encoder (but you must buy an option card for the VFD and mount it). The data registers you are looking...
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    2$$
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    156

    Is the equipment hard wired or plugged in? Is it...

    Is the equipment hard wired or plugged in?
    Is it a medical clean room?
  4. Actually, I was jumping the gun a little. I used...

    Actually, I was jumping the gun a little. I used to be an integrator for a VFD line that had a built-in line reactor on every drive (they went under). That was the first time I ever encountered EMC...
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    11$$
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    So you used the term "GFP monitor", and that...

    So you used the term "GFP monitor", and that makes me question this. There are Ground Current Monitors, and there are GF Protection (Trip) units, although sometimes the word "monitor" is also in...
  6. Well there you go. I don't remember having seen...

    Well there you go. I don't remember having seen that chart in UL891, but then again I've been out of the design end of the business for over a decade now and I can't find my copy of 891 any more....
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    20$$
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    512

    Every time someone asks me how I came know all...

    Every time someone asks me how I came know all this stuff (which my wife calls "useless"), I answer the same way.

    "One mistake at a time, although sometimes the same mistake more than once."
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    22$$
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    839

    Exactly. I used to put in panelboards at...

    Exactly.

    I used to put in panelboards at Boeing facilities, they had an extra complicated door-in-door arrangement requirement that Westinghouse had developed just for them in the 60s, but when...
  9. Well, I think too it has to do with how you are...

    Well, I think too it has to do with how you are defining "between".

    UL891 is, I BELIEVE (don't have my copy here) referring to "between bus bars"., that's why the shape and orientation of the bars...
  10. Replies
    20$$
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    512

    That's a phenomenon that you only see pretty much...

    That's a phenomenon that you only see pretty much in Japanese drives like Yaskawa, Mitsubishi etc, and is more of a marketing and UL listing issue believe it or not. Japanese drives are primarily...
  11. First off, lets get past the semantics. Your...

    First off, lets get past the semantics. Your title mentions interrupting rating, bus bars do not interrupt anything. They need to have bracing for withstanding the mechanical stresses of the magnetic...
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    20$$
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    512

    You cannot conflate current and power,...

    You cannot conflate current and power, specifically BECAUSE of Power Factor.

    100kVA at 480V 3 phase = 100,000/1.732 x 480V = 100,000/831.36 = 120A

    100kW at 480V, assuming a .8 power factor, =...
  13. The order doesn't actually matter. The Line...

    The order doesn't actually matter. The Line reactor is in series with the drive, the EMC filter is in parallel. Generally though, the EMC filters are attached right to the drive (or built in), so the...
  14. I'm guessing Southern California Edison (the...

    I'm guessing Southern California Edison (the largest PoCo in SoCal) and a 5 jaw meter socket, because what he had before was a 240/120 3ph 4wire service, and now he is being fed 240V delta, no center...
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    20$$
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    512

    Actually no, he said these are MATRIX inverters...

    Actually no, he said these are MATRIX inverters (actually, converters), it's a totally different power topology from what we all know and love as "VFDs". It's referred to as an AC-AC Converter, as...
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    22$$
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    839

    The funny thing to me is, they did a nice job...

    The funny thing to me is, they did a nice job with the door itself, but then used a cheesy little slide bolt on it from the hardware store... :slaphead:
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    22$$
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    839

    Doors on UL 67 listed panelboards are not part of...

    Doors on UL 67 listed panelboards are not part of the UL listing at all. The interior/bus, trim and box are all that is included. The doors are for convenience. You can not install the doors at all...
  18. Replies
    5$$
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    211

    If it's 200A maximum load at 208V 3 phase, that's...

    If it's 200A maximum load at 208V 3 phase, that's a 75kVA transformer (with near zero head room), but the only alternative would be a 112.5kVA and run it at <70% loading, which has some efficiency...
  19. Thread: 3 motor drives

    by Jraef
    Replies
    12$$
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    407

    Make and model of the drives?

    Make and model of the drives?
  20. Thread: MTE DVDT Filter

    by Jraef
    Replies
    5$$
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    186

    Bread slices make for a lousy LRC low pass filter.

    Bread slices make for a lousy LRC low pass filter.
  21. Thread: 3 motor drives

    by Jraef
    Replies
    12$$
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    407

    So confirm that this is correct. You have a 50A...

    So confirm that this is correct. You have a 50A CB feeding the drive supply circuit with #8s, which go into a splitter block or something that separates that into another #8 feed into the bigger...
  22. Thread: MTE DVDT Filter

    by Jraef
    Replies
    5$$
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    186

    It's a reactor + a capacitor and resistor making...

    It's a reactor + a capacitor and resistor making it an LRC low pass filter. I use them all the time when the lead length from motor to drive exceeds the maximum recommendation of the drive mfr. By...
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    21$$
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    Yeah, GE has a fantastic line called Tranquell...

    Yeah, GE has a fantastic line called Tranquell too that I think, based on the weight and price, must be made of solid gold.

    I had a pump station get hit by a direct lightning strike and the main...
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    11$$
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    463

    I didn't know (or maybe remember) any of this...

    I didn't know (or maybe remember) any of this until late in my career when I went to work for Siemens in 2006. I attended a training module on Switchgear and Transformers and thought "I can teach...
  25. Thread: OSHA questions

    by Jraef
    Replies
    15$$
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    668

    To chime in on these points, from an OSHA...

    To chime in on these points, from an OSHA standpoint, YOU as the boss are required to have a policy, review the policy and ensure that your employees know and review the policy periodically. What...
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