Which type of 3 phase converter should I implement? - Page 3
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  1. #41
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    Quote Originally Posted by homer14 View Post
    im surfing around, comparing prices, learning, finding surplus places vs ebay vs whatever...

    i run into these two, probably cheap parts, panels:

    $350.00, 60 sold
    10hp Cnc Balanced 3 Phase Rotary Converter Panel 10 year warranty! | eBay

    $231.00, 86 sold
    Rotary Phase Converter Panel ONLY AD10-STK- DIY 10HP Convert 1 to 3 PH USA | eBay


    Now im wondering... i suppose we could assume the caps are probably the newer less oil filled or non oil filled junk ones... the balance wont be perfect... and some breakers, fuses, and what not could be added.. but if one bought one of these then one could potentially add/remove caps to fine tune the balance and anything else necessary possibly.. potentially needing all new oil filled caps (could email seller and ask)...

    these are way cheaper, again probably for a reason, than buying caps, enclosures, contactors, etc. are they worth it i wonder? i expect to hear a bunch of shit now. hehe
    Jim Gorman, PM member "Phase-Craft". .like his RPC boxen brand.. built value for money 'til he retired (again).

    I HAD all the parts easily twice over at the time, but couldn't be bothered to even lay out the dam' parts and drill the holes for everything.

    NOW? I find meself modifying his controller ANYWAY.

    Part of the deal with triple idler selection and "teaming" is "start any ONE", add others later - or drop them offline - but place their balance caps on each, individually, AND NOT in the main controller's box as it was built for ONE idler.

    What DIY buys you the MOST of? Understanding. And "certainty".

    You know what is in it, and how to fix it, because YOU learnt the design, and YOU put it all IN there.

    An RPC is actually a degree or three SIMPLER than the average box of rocks.. and yet?

    Folks arrive here with one they bought or inherited.. and soak up as much as two whole months fighting themselves whilst trying to sort them out.

    Go figure...

  2. #42
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    Quote Originally Posted by JST View Post
    ..... let's not get too far off topic
    You guys can talk about cats or whatever you want. I know you're weirdos and enjoy the side convo's while you teach newbies like myself. talk anything you want, I can filter out the answers directed to me along the way.

    i had a cat that used to steal socks from my dresser drawer if left open. it was a cold basement room i was in at the time and i liked my socks in the morning. so it pissed me off. think salami-wrapped-pickle snacks... the trick was to take a small rectangular rug like one you would see on a door way. aim for a rug with a width slightly shorter than the cat's length. then locate the cat and gently lay it out long wise holding its legs outward (like stretched a bit). then while petting the cat and saying nice things you curl an edge of the under the cat and begin to roll it, like a pickle within salami with cream cheese. continue to speak nice to the cat and carry it down stairs under your inner arm holding it carefully to keep the roll together. now this is the tricky part... lay some socks down on the floor. lay the cat roll next to the socks with visual of the socks. walk away for an hour prior to return to release the cat. your socks will now remain in your drawer.

    ok back to cap hunting.

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    Quote Originally Posted by homer14 View Post
    prior to return to release the cat. your socks will now remain in your drawer.
    Alternative method: Put the battery charger on the cat. Return, seek two-lane Appalachian blacktop.

    On Continental Gummiwerke's best Lebanese tennis shoes, even a fifteen-year-old X350 Jaguar can still knock your socks off with four seats full of smiling folks and a boot full of enough luggage for a week's "genuine" Grand Touring!


    ok back to cap hunting.
    What Is The Difference Between 370 Vac And 440 Vac Capacitors

    Peace of mind on our HIGHLY inductive load-motors and their arcy-sparky contactors. Only a modestly higher initial cost than the the lower-rated ones.

    Hunt ye bargains on the idler motor(s).

    But go first-table on contactors, relays, and caps. Wire and its terminations as well. Of Course.

    Hacker's Laws:

    - I hate doin' DUMB STUFF "twice".

    - Sex is granted an exception.

    No help for it.

    See Lord Chesterfield's quote on that.

  4. #44
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    this looks tempting.

    CP-10: 10-HP Rotary Phase Converter Control Panel | NAPCco

    though diy comes with everything said prior... education, confidence, quality, etc... that versus a quick solution above that may need some tweaks...

    does the start cap need to be oil based or can it be other while the run caps are oil based.. i guess the answer may simply lie in how long it will last.

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    Quote Originally Posted by homer14 View Post
    this looks tempting.

    CP-10: 10-HP Rotary Phase Converter Control Panel | NAPCco

    though diy comes with everything said prior... education, confidence, quality, etc... that versus a quick solution above that may need some tweaks...

    does the start cap need to be oil based or can it be other while the run caps are oil based.. i guess the answer may simply lie in how long it will last.
    My view, having had to procure, specify, deliver - or all of the above, and "for a crust" to USACE, other MIL-SPEC & "(n) letter" Federal agency, Dominant-Carrier Global Telco, more than several non-US specs, and "Hospital Grade" commercial goods?

    Is that if "store bought" does NOT also bring me UL/CSA/TuV or comparable national certification?

    I am better-off, not worse-off, to DIY to my usual high (if-not-also-OCD-anal overkill) standards. Those credentials are dice-roll bullshit easily half the time in any case. All they REALLY do is keep yah sweet with Inspectors and inch-hoorance adjusters if the rig goes up in flames or kills some poor bastid.

    YMMV ... if your pension was earned as a house painter!



    Many, "Right here, on PM", build-up an array of longer-lived "run" caps to hit the capacitance target for a "reasonable" start-cap value. The value isn't super-critical with "start" caps, anyway.

    I WAS heading that direction, but nooo.

    Just build it so the start cap is easily accessed for replacement and dasn't trash it's bedpartners if/as/when it hand-grenades. Sheet metal barrier, same box. Or separate box. "Wire exists".

    Then figure to replace it once or twice over rather very long years with a nice FRESH one. AND NOT one stashed as a spare, same manufacture date.

    They degrade with age as well as use.

    And.... they just aren't all that costly nor so fragile, either one, that yah need them to try for "immortality".

    Paralleled "run" caps in "start cap" service can require MUCH larger enclosures.
    A BIG idler, that can get to the size of a microwave oven? More pain than gain.

    Good grade of start cap. Spacious enclosure for it.

    Go solve some needier problem.

    2CW

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    I've also been thinking about building an RPC to better power my 3hp Hendey. The question I have is this: the selection of run capacitors sounds like it's an iterative process. Is there a good way to cut down on buying expensive ones that you end up not using?

    Sent from my Nokia 7.1 using Tapatalk

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    Quote Originally Posted by jerholz View Post
    I've also been thinking about building an RPC to better power my 3hp Hendey. The question I have is this: the selection of run capacitors sounds like it's an iterative process. Is there a good way to cut down on buying expensive ones that you end up not using?

    Sent from my Nokia 7.1 using Tapatalk
    There are recommendations for sizing caps, but when it comes down to the wire its cut and try.

    Tom

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    A simple method is to just use a much larger than required idler. It will generally give better performance on different loads than a capacitor-adjusted RPC.

    If you really will have just ONE load, then you can likely do the iterative process or other method, and arrive at a value that suits that load pretty well..

    As for avoiding that, yes, it can all be calculated. BUT, you need to know a LOT more about the motors, both the idler and the load. Generally one does not, and few want to do all the calculation , even if they know how and have the data, because it is fairly easy to just try them based on a "typical estimate" as a starting point. And even the most ideal value capacitor is really a compromise.

    Remember, the ideal source is just a big generator that "does not notice" the load you will put on it. In other words, the electrical grid and powerco. You are just trying to imitate that.

  9. #49
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    Quote Originally Posted by jerholz View Post
    I've also been thinking about building an RPC to better power my 3hp Hendey. The question I have is this: the selection of run capacitors sounds like it's an iterative process. Is there a good way to cut down on buying expensive ones that you end up not using?

    Sent from my Nokia 7.1 using Tapatalk
    I had the same thoughts... I also saw other posts where people asked for guidance too... then I just wrote this down to start with in regard to the 10hp fitch design. i expected i'd likely need to buy one or two more and also to not use one or two of them.

    100 x2
    50 x4
    15 x5
    30 x2

    after this you'll start to look for the contactors, transformer, etc. and begin to see the costs start adding up. then youll begin to question buying a starter panel/box from a company that makes them and fine tuning it vs making your own which might cost you more and the pros/cons of both of those options. thats where im at right now!

    i feel diy is the way to go and you'll end up with confidence, hopefully quality, and an understanding but it will cost you more i think than they ones out there near-ready right now. i need to resolve this brain conflict myself still.

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    Quote Originally Posted by jerholz View Post
    I've also been thinking about building an RPC to better power my 3hp Hendey. The question I have is this: the selection of run capacitors sounds like it's an iterative process. Is there a good way to cut down on buying expensive ones that you end up not using?
    Surely. Don't be overly anal about seeking "balance" to begin with.

    It can make sense to "tune" for a dust collector or an HVAC air-handler as runs near-as-dammit "steady state" and is the sole and only load on a "dedicated" RPC.

    It does NOT make as much sense for a lathe or mill that by definition does NOT run at "steady state" ... and isn't even the ONLY load for a general-purpose "shop-wide 3-Phase source" RPC in any case.

    Build with the values the late Fitch Williams provided.. or near-as- dammit, "scaled" up or down from his convenient "10 HP" model. He DID "10 HP' to make the math easier, after all. Take advantage of that, then round to the nearest standard value.

    Then JF run the RPC.

    More than a few PM members (and "not only") have been running RPC with NO CAPS AT ALL, and for a lot more than just ten straight years as well.

    RPC are just NOT snowflake-fragile critters. Bulletproof-durable and highly forgiving, rather.

    That's why we Grey-hairs prefer them over touchy-fragile shorter-lived Vee Effing Dee to begin with.

    RPC as a tribe ain't "enough broken" to need a lot of fixing.

    Not unless f**king about is the ACTUAL "project" anyway?

    DAMHIKT, either.. third idler due on my doorstep... tomorrow..!!!


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    Could not one also plan on the high side with capacitors and then start switching some to series to reduce the capacitance without having to remove an entire capacitor?

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    i read on these forums somewhere that the fitch setup uses a 240 to 120 transformer because of the contactors at 120. also that if the contactors were 240 then the transformer would not be needed. perhaps this was/is due to commonly available parts?

    if correct, would there still be two contactors in play, the run contactor and the start contactor? and would those two contactors need to become 240v contactors (40amp 3 pole 240, and a 30amp 3 pole 240)?

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    They do make 240v coil contactors, that's what we have.

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    im a bit lost at the moment on the 240 to 120 transformer... if i have two legs of 120 coming in from a single phase side, wouldnt i just pop those into a a 120 contactor? like the one in the attached pic (with 3 poles)

    EDIT: i cannot seem to remove aprior attached 2 pole contactor photo, please ignore that one.
    Attached Thumbnails Attached Thumbnails 2polecont.jpg   3pole120cont.jpg  

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    Quote Originally Posted by ClappedOutBport View Post
    Could not one also plan on the high side with capacitors and then start switching some to series to reduce the capacitance without having to remove an entire capacitor?
    Not as if yer trying to tune HCJB from Tanana, Alaska on shortwave with a 1938 triple-stage TRF plus double-conversion superheterodyne hollow-state receiver, here...

    You planning to do this piddly shit whilst in the cut as yer lathe climbs a taper?

    More interesting to grab a 12-bore, load with high-brass numbah one buck... put on a pair of "telesights", slip stealthily into the back garden .... and reduce the population of BEETLES!

    Aim well. Bug-ers may charge if only wounded, and yah don't wanna mess-up the trophy-heads nor the best cuts of meat, neither! Ain't got a hair on yerazz yah cheat and use a lead-dust "door-opener" charge, BTW.

    Machine-tool don't buck, stall, vibrate, chatter its contactors, load motor(s) don't overheat? She's happy enuf.

    That's how yah know yah HAVE an RPC instead of a silly "static" converter-NOT!

    That simple. Really. They are.

    Ain't never yet met no RPC as had to sit down to pee!

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    ive got some parts ready to purchase (contactors and run caps mainly).. im trying to toss more into the order if i can but need to better understand a couple of parts.

    do i need the 240vac to 120vac transformer as in fitch's design? in a youtube video i keep watching i dont see a transformer at all. just 240 power into a magnetic contactor (guessing a 240v rated coil one?) and then no more contactors after that. im fairly certain the video is using fitch's design too but not quite the same way. the fitch model has a couple of contactors which are in my parts list but im studying the diagram wondering how/where they connect up which is part of my problem versus the videos that are clear but done differently.

    what about a potential relay or relays to drop the start caps out after potential detected. if yes, what voltage rating 240?, 120?

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    Quote Originally Posted by homer14 View Post
    ive got some parts ready to purchase (contactors and run caps mainly).. im trying to toss more into the order if i can but need to better understand a couple of parts.

    do i need the 240vac to 120vac transformer as in fitch's design? in a youtube video i keep watching i dont see a transformer at all. just 240 power into a magnetic contactor (guessing a 240v rated coil one?) and then no more contactors after that. im fairly certain the video is using fitch's design too but not quite the same way. the fitch model has a couple of contactors which are in my parts list but im studying the diagram wondering how/where they connect up which is part of my problem versus the videos that are clear but done differently.

    what about a potential relay or relays to drop the start caps out after potential detected. if yes, what voltage rating 240?, 120?
    None of the above. I use nominal 24 V. OSHA prefers that. For once, I agree.

    My "mechanical" & Mercury-Displacement contactors are 24V. My Crydom's are happy with it as well ( 3 or 5 to 35 V, and DC, even) .

    24 control transformers have become as common as housefly feces. Sourcing them has not been a problem in easily a hundred years.

    Why would I want to stock components for more than one control voltage or depart the 50 V max for wire-runs as "class 2" field wiring of controls.

    Anything from ignorant 1920's doorbells to thermostats to.. RPC?

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    so i could/should replace both of these?

    DP CONTACTOR, 40 AMP, 3 POLE, 120 VOLT.
    DP CONTACTOR, 30 AMP, 3 POLE, 120 VOLT.

    with this?

    24vac.jpg

    and wire a 120/240 -> 24vac transformer to it to actuate it?

    then no contactors needed after that? i only need the one contactor, not the 2 fitch mentions?

    -------

    couldnt i skip needing a transformer at all and just get the "DP CONTACTOR, 40 AMP, 3 POLE, 120 VOLT" and actuate it with a 120v push button?

    sorry about all of the questions.

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    k. after the fun of searching parts and watching videos, talking to experts, etc. ive decided to order a phase converter panel. when i get it i will tweak it using the fitch model and capacitor tuning. i hope to save some money and speed this up by going this route while also still learning and understanding what is going on in the panel plus fine tuning it as i would have done if building my own.

    stay tuned!

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    The control voltage change doesn't change anything other than part numbers. You still need two contactors.

    It can be helpful to draw your diagrams as separate control & power drawings.


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