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  1. Replies
    30$$
    Views
    1,554

    I had not heard of Vienna bridge rectifiers until...

    I had not heard of Vienna bridge rectifiers until I googled them. Very interesting. Active rectification crossed with SMPS tech. Very cool. Looking at needing 60A @ 70VDC peak. Much lower...
  2. Replies
    30$$
    Views
    1,554

    Shouldn't the average DC voltage be higher...

    Shouldn't the average DC voltage be higher (assuming appropriate filtering) with three phase rectification?
    The value of:

    VDC = (VAC * 1.65)

    makes sense intuitively, as there is inherently...
  3. Replies
    20$$
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    1,099

    Your client is the 3rd party. If their building...

    Your client is the 3rd party. If their building burns down, the device failed the test. :blink:


    SceneryDriver
  4. Replies
    30$$
    Views
    1,554

    Transformer and rectifier math

    All,
    I posted this question over at plcs.net, and didn't really get a good answer so I'm asking here:

    My transformer and rectifier math for 3-phase supply is a bit rusty.

    I'm looking to...
  5. Replies
    10$$
    Views
    525

    I was surprised the first time I read that, too. ...

    I was surprised the first time I read that, too.

    I wonder how long it will be before we get into the definition of a "large" residential pool. :D



    SceneryDriver
  6. Replies
    10$$
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    525

    Quote from UL 508A, emphasis mine: "Also...

    Quote from UL 508A, emphasis mine:

    "Also covered are industrial control panels intended for control of permanently installed
    electrical equipment for aquatic playgrounds, permanently installed...
  7. Replies
    10$$
    Views
    525

    A transformer listed for pool/spa use seems to be...

    A transformer listed for pool/spa use seems to be the safest, most correct way to do it (GFCI protected, of course).

    Know also that you will almost certainly need an interposing relay between...
  8. Replies
    9$$
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    935

    If your VFD's loose supply power, they will most...

    If your VFD's loose supply power, they will most likely fault and will not ramp your load to a stop. If dropping the brakes unexpectedly will cause a mechanical overload to the system, consider...
  9. Replies
    10$$
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    1,937

    PoCo doesn't care if an idiot blows himself up or...

    PoCo doesn't care if an idiot blows himself up or he burns down his house doing something stupid; they care about getting paid. Downstream of the meter, they get paid either way.


    Scenerydriver
  10. Replies
    4$$
    Views
    328

    Just because you can doesn't really mean you...

    Just because you can doesn't really mean you should. The cost of the splices (probably Polaris connectors) j-boxes, and labor could pay for a lot of #4 wire.

    This sounds like a residential...
  11. Replies
    5$$
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    256

    LED's forward voltage drop decreases with...

    LED's forward voltage drop decreases with increasing junction temperature. The driver is indeed reducing drive current to the LED strings (by lowering the voltage) as the LED's heat up. If the...
  12. Replies
    18$$
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    2,031

    I've used these to create vents / drains in...

    I've used these to create vents / drains in conduit systems several times:
    ...
  13. Replies
    76$$
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    3,515

    You are correct; I've never run into a situation...

    You are correct; I've never run into a situation where anything that was part of a set was considered as needing a permit. Even equipment that is installed as part of a production that will be there...
  14. Replies
    76$$
    Views
    3,515

    Exactly. I'm not a licensed electrician. I'm an...

    Exactly. I'm not a licensed electrician. I'm an industrial controls designer who happens to design and build things for the Lighting and Entertainment industry. In fact, there really is no...
  15. Replies
    5$$
    Views
    418

    PE signing plans

    In a recent "Trading Post" post, a member asked sought a PE to stamp electrical and structural plans for solar installations.

    Charlie B replied with:

    "Since you seek someone to sign plans, and...
  16. Replies
    18$$
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    867

    Cord grip. Sometimes called a domenut. The...

    Cord grip. Sometimes called a domenut. The locknuts come separately, so make sure to order those too.

    https://www.alliedelec.com/product/lapp-group/s2112/70123693/


    SceneryDriver
  17. The needed temperature rating of the wire is all...

    The needed temperature rating of the wire is all going to depend on the temp rating of the terminals on the heaters. If they're marked for 90C or less, you can use XLPE insulated conductors. The...
  18. Replies
    18$$
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    1,227

    And I forgot to add: This is really a completely...

    And I forgot to add:
    This is really a completely immaterial discussion. Since this receptacle - mounted in the wall of the set - is cord and plug connected, it is utilization equipment and isn't...
  19. Replies
    18$$
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    1,227

    Short answer: nothing "bad" would happen to you,...

    Short answer: nothing "bad" would happen to you, any worse than touching any other not-properly-grounded devices. That's why you make sure everything is properly grounded (or double-insulated), but...
  20. Replies
    18$$
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    1,227

    I work in the Entertainment industry, and I can...

    I work in the Entertainment industry, and I can tell you this is common practice. It's often a necessity, as onstage lamps (practicals) must be controlled with the rest of the stage lighting. The...
  21. Replies
    9$$
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    469

    "Not all good ideas are code-enforceable." The...

    "Not all good ideas are code-enforceable." The fuses are cheap insurance, code-required or not. I'd certainly put them in.



    SceneryDriver
  22. Replies
    9$$
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    469

    What size is the control wiring? ...

    What size is the control wiring?


    SceneryDriver
  23. Replies
    10$$
    Views
    684

    Use Tray Cable with the appropriate number of...

    Use Tray Cable with the appropriate number of conductors, supported from a 1/8" aircraft cable messenger wire. Attach the tray cable to the messenger with UV-resistant, UL-listed zip ties.


    ...
  24. How will the electrons know about the bend in the...

    How will the electrons know about the bend in the rod? Why would it possibly matter? The rod is, after all, in contact with the earth along its entire length regardless of orientation to the...
  25. Soft starters may have issues with...

    Soft starters may have issues with corner-grounded delta power. Most soft starters (and many VFD's, though I know they wern't mentioned here) expect and require wye-connected power. Some may be...
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