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    16$$
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    3$$
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    Well this is an open and shut case. It helps to...

    Well this is an open and shut case. It helps to once in a while go back to the NEC articles that you end up using all the time because you start taking them for granted.

    Second sentence of...
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    3$$
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    289

    Motor Circuit Protector Multiple Feeder

    Hello,

    If I had a MCCB (Molded Case Circuit Breaker) and needed to size it for multiple motors I wouldn't have an issue. Get the OCPD of the largest motor and then add the FLA of the second. Each...
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    16$$
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    1,603

    I spoke with the drive manufacturer. Their model...

    I spoke with the drive manufacturer. Their model drive in question comes standard in Open Loop control, however, the model drive has such a rudimentary torque control model even in Open loop vector...
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    16$$
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    From Jraefs post above the drive always seems to...

    From Jraefs post above the drive always seems to have to start at 0 and ramp up. I would ultimately would like to send 50% voltage and 50% speed command initially to the motor. This will guarantee...
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    16$$
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    So that is the question right there. Suppose you...

    So that is the question right there. Suppose you set the min speed. It is at a dead still. The motor cannot move at 0Hz, 1Hz, or 2Hz. The drive still keeps ramping to the 3Hz mark (it doesn't care...
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    16$$
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    yeah that is the question. What’s stopping the...

    yeah that is the question. What’s stopping the drive from starting at 3hz or whatever larger frequency so that high starting loads can be started with V/Hz mode.
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    16$$
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    yes, I was going to suggest open loop control but...

    yes, I was going to suggest open loop control but I just wanted to get the theory if I could have the drive in V/Hz mode start outside of the “muddy” low range. Have it start at 3Hz, 10Hz, 15Hz what...
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    31$$
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    Contractor should submit all cut sheets so that...

    Contractor should submit all cut sheets so that the equivalency determination can be made by the reviewer. If the item meets all of the specification requirements, point for point, without even the...
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    16$$
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    1,603

    VFD - V/Hz High Breakaway Load

    Hello,

    Here are the facts:

    VFD Drive
    No Encoder
    V/Hz Control mode
    Load is Constant Torque, with high starting torque required
    Motor = 1800RPM rated with 3% slip, 460V rated
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    5$$
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    Pad Mount Transformer

    Hello All,


    I wanted to see if there is anywhere else in the NEC that dictates the space requirements around a big green oil filled pad mount transformer.

    110.32 says that the work space...
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    51$$
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    There is GF detection after the ATS (on the load...

    There is GF detection after the ATS (on the load terminals) on the branch that "feeds" the zig zag transformer. It monitors the 3 phases. I really do not think the Zig Zag was an after thought, I...
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    51$$
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    4,119

    If there were grounding conductors and if the ATS...

    If there were grounding conductors and if the ATS accepted the grounded conductors from each service at the pier, one way around connecting the two service grounding conductors would be for a...
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    51$$
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    4,119

    This would have been if they instituted a regular...

    This would have been if they instituted a regular wye secondary. I missed that it was a delta and no connection to the utility since it is a SDS. Seems like the designer choose very specifically to...
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    51$$
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    Correct, the 208V Delta to 480V Delta step-up...

    Correct, the 208V Delta to 480V Delta step-up transformers (one on each side of the river) are client owned and are separately derived systems from the 208/120V utility supply.
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    51$$
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    Correct they are SDS's. Correct, it is actually a...

    Correct they are SDS's. Correct, it is actually a 208V Delta to 480V Delta transformer for each end. This is odd to me, its almost like doubling down on not having a neutral there. They could have...
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    51$$
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    4,119

    There is lighting load at the pier, but that is...

    There is lighting load at the pier, but that is handled by a separate lighting transformer at the pier that is a 480-208/120 transformer. The submarine cables from each shore utility do not have a...
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    51$$
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    Wouldn't the saving on 3 pole ATS vs 4 Pole ATS...

    Wouldn't the saving on 3 pole ATS vs 4 Pole ATS being nulled by the purchase of the zig zag transformer?

    The saving on copper isn't likely since the submarine cables are custom products which the...
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    51$$
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    Why did the designer Zig and Zag

    Hello, I have a scenario where I am scratching my head as to why the original designer went through all of the complexity to require a Zig Zag transformer. Maybe some one here can give me a different...
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    23$$
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    Ah, I see what you are saying.

    Ah, I see what you are saying.
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    23$$
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    Good point, I choose a poor example. Suppose you...

    Good point, I choose a poor example. Suppose you paralleled 2 - 1/0 to make a 2/0 equivalent. Or you are saying since Ground Electrode conductor is not specified and only "Grounded Circuit" is...
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    23$$
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    I thought I read once in the forum that the NEC...

    I thought I read once in the forum that the NEC is a permissive Code meaning that if it doesn't forbid it then it is allowed, or was it the opposite that I read?
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    23$$
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    Parallel Sets of GEC

    Suppose the GEC required is a 2/0 AWG. If you run 3 sets of #4AWG and irreversible bond both ends of the cables, would that be a code violation?
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    9$$
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    Yeah I agree this sounds the way it would go on a...

    Yeah I agree this sounds the way it would go on a new system.

    Yeah interesting to see what the rest of the country experiences for Annual and Semi annuals.

    Also another view point is...
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    9$$
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    Interesting points. I did not know anyone else...

    Interesting points. I did not know anyone else besides Architects and Engineers carried E&O.
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