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Type: Posts; User: Jraef

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  1. Replies
    9$$
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    256

    I just looked at the manual for a Trane 3 phase...

    I just looked at the manual for a Trane 3 phase unit we have here, it says "Max. Circuit Prot. Device .... 15A". It doesn't distinguish between a CB or fuses. Most commercial units (which is where...
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    2$$
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    161

    In V/Hz there is no inner control loop, that is...

    In V/Hz there is no inner control loop, that is correct. The VFD puts out a V/Hz ratio commensurate with the commanded speed, but has no idea if the motor responded, or in many cases if the motor is...
  3. Thread: Challenger

    by Jraef
    Replies
    2$$
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    207

    Challenger is long gone, although parts of them...

    Challenger is long gone, although parts of them were rolled into Eaton through mergers and acquisitions. You might try an Eaton distributor.
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    860

    It may not be in the NEC, but it's entirely...

    It may not be in the NEC, but it's entirely possible that YOUR FACILITY has a standard, written or not, that they want you to follow so that the next person to open that box does not have to second...
  5. Thread: 3 phase motor

    by Jraef
    Replies
    5$$
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    239

    To expand a bit: 240V is the national standard...

    To expand a bit:

    240V is the national standard for "Distribution Voltage" (ANSI C84.1); meaning what the utility is supposed to supply to the Service Entrance point. Distribution Votlage is...
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    Common sense is however not codified... :angel:

    Common sense is however not codified... :angel:
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    3$$
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    430.122 REQUIRES that conductors feeding a VFD...

    430.122 REQUIRES that conductors feeding a VFD are sized at 125% of the INPUT CURRENT rating of the VFD. There is no allowance for what you have programmed into the VFD, in fact that is the INTENT of...
  8. Thread: Harmonics and PF

    by Jraef
    Replies
    7$$
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    409

    Not AFE drives, an Active Harmonic Filter that...

    Not AFE drives, an Active Harmonic Filter that connects to the distribution panel or MCC bus and injects corrective current which corrects all harmonics up to about the 50th from any source on that...
  9. Thread: Harmonics and PF

    by Jraef
    Replies
    7$$
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    409

    How much harmonic current are we talking about...

    How much harmonic current are we talking about here? I’ve been using Active Harmonic Filters on some projects now for a few years, the results are great, both from a harmonica standpoint and from a...
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    3$$
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    You are describing something that is trickier...

    You are describing something that is trickier than most people realize. Any modifications done to the power structure of an MCC by anyone other than the mfr of the MCC will void the UL845 listing not...
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    I believe the issue has to do with the fact that...

    I believe the issue has to do with the fact that NFPA 20 now allows the Fire Pump Controller mfrs to use Instantaneous Trip (aka MCP) breakers in the controllers. They do not have thermal / long time...
  12. The lower drawing is not really something that...

    The lower drawing is not really something that people do very often, but people DO use the secondary windings separately as separate isolated circuits quite often. Each individual winding would have...
  13. Thread: OCPD at MDP

    by Jraef
    Replies
    4$$
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    239

    If the main service disconnect has a breaker or...

    If the main service disconnect has a breaker or fuses that are no more than 600A and the conductors are rated for that OCPD, then yes, he is correct. You only need it in one place. Now from a...
  14. Thread: Feeder Size

    by Jraef
    Replies
    6$$
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    411

    Well, I'd put it the other way around. The feeder...

    Well, I'd put it the other way around. The feeder OCPD is there to protect the conductors. If you want to over size the conductors compared to the OCPD, you are welcome to. That happens quite a bit...
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    10$$
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    516

    Please done cross post. Duplicate threads have...

    Please done cross post. Duplicate threads have been merged.
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    10$$
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    516

    I would use contactors and a smart relay (or a...

    I would use contactors and a smart relay (or a bunch of relay logic) to only allow one circuit to be energized at a time.

    Or use a rotary selector switch with 5 positions so that power can only go...
  17. Thread: Feeder Size

    by Jraef
    Replies
    6$$
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    411

    CAN'T be? No, not true. The conductors could be...

    CAN'T be? No, not true. The conductors could be sized for a larger feeder circuit, so long as the feeder breaker is appropriate for those conductors, because your panel has it's own main breaker. So...
  18. Pull the ground wire from the MCC ground bus....

    Pull the ground wire from the MCC ground bus. Then also run your ground to the motor directly to the VFD ground terminal, NOT to a ground lug or bus in the VFD cabinet. There is likely a 2nd ground...
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    15$$
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    686

    Glad it worked out. :thumbsup:

    Glad it worked out. :thumbsup:
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    15$$
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    686

    Yeah, after the 50th time seeing the same tham...

    Yeah, after the 50th time seeing the same tham ding over and over again, you learn to expect it...
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    866

    I once pointed out a glaring electrical hazard to...

    I once pointed out a glaring electrical hazard to someone as I walked through a lumber mill on my way to a project. I wasn't there to address it, but I couldn't un-see it. The next time I went there...
  22. If the gear in question is not listed as Arc...

    If the gear in question is not listed as Arc Resistant, it's irrelevant in that the cover is not actually required to remain intact in an arc blast event. There are no standards other than those for...
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    15$$
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    686

    5:1 odds it's an air compressor and another 5:1...

    5:1 odds it's an air compressor and another 5:1 that the unloader is stuck closed so it's trying to start the compressor loaded. :p
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    3$$
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    321

    Actually in all cases. Panel bus sizes are only...

    Actually in all cases. Panel bus sizes are only going to be among a few ratings, different from one mfr to another. 60A, then 100 or 125A, 200/225/ 250A, 400A, 600A, 1200A etc. So if you need a 90A...
  25. Replies
    15$$
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    686

    Electrically, on a 3 phase motor the only thing...

    Electrically, on a 3 phase motor the only thing that could cause this is a bad connection, i.e. a partial single phasing condition. If one phase was completely lost the motor would not start at all,...
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