RPC phase loss protection
Close
Login to Your Account
Results 1 to 17 of 17
  1. #1
    Join Date
    Mar 2014
    Location
    Michigan
    Posts
    919
    Post Thanks / Like
    Likes (Given)
    254
    Likes (Received)
    381

    Default RPC phase loss protection

    Iíve been running a 20hp Phase Craft converter set up for the last few years and itís been flawless. I have a 60amp un-fused disconnect between the Phase Craft and the idler motor. I had the boys doing some cleaning/painting around the shop so I turned the power off to everything.

    I turned the single phase converter power power back on but forgot to flip the idler disconnect switch. The 20hp idler made the awful noise it was supposed to for 1.5 seconds until the power was turned off.

    I usually turn the disconnect off on my little Blanchard grinder but I mustíve forgot. I looked over and seen the white magic smoke rolling out the top of the magnet controller. It still works the way itís supposed to....for now

    I wonít repeat the idler disconnect mistake but I don't want phase loss power going to my machines again. The idler motor FLA is 48 at 240V.

    1) Would a solid state overload relay placed before the 3 phase load center protect the idler motor and phase loss?

    2) Is the relay install just hooking up the power in/out and the ground?

    3) Does it matter which way the idler motor spins? Iíve read some conflicting opinions on that.

    Thanks in advance.
    Andy

  2. #2
    Join Date
    Aug 2012
    Location
    California, Central Coast
    Posts
    5,508
    Post Thanks / Like
    Likes (Given)
    2434
    Likes (Received)
    2314

    Default

    You could put a 3 phase contactor on the output of RPC and wire the generated leg to pull the coil shut on that contactor. That way if RPC is not generating power the contactor is open an no power goes through.

  3. Likes Hobby Shop, neilho liked this post
  4. #3
    Join Date
    Mar 2009
    Country
    UNITED STATES
    State/Province
    California
    Posts
    6,609
    Post Thanks / Like
    Likes (Given)
    131
    Likes (Received)
    1275

    Default

    Use the disconnect between the Phase Craft and incoming single phase power. Connect the idler directly to the converter with a contactor with a overload block that has
    phase loss detection. It doesn't matter which direction the idler rotates.

  5. Likes Hobby Shop liked this post
  6. #4
    Join Date
    Sep 2011
    Country
    UNITED STATES
    State/Province
    Virginia
    Posts
    22,148
    Post Thanks / Like
    Likes (Given)
    7561
    Likes (Received)
    12732

    Default

    Quote Originally Posted by Hobby Shop View Post
    I’ve been running a 20hp Phase Craft converter set up for the last few years and it’s been flawless. I have a 60amp un-fused disconnect between the Phase Craft and the idler motor. I had the boys doing some cleaning/painting around the shop so I turned the power off to everything.

    I turned the single phase converter power power back on but forgot to flip the idler disconnect switch. The 20hp idler made the awful noise it was supposed to for 1.5 seconds until the power was turned off.

    I usually turn the disconnect off on my little Blanchard grinder but I must’ve forgot. I looked over and seen the white magic smoke rolling out the top of the magnet controller. It still works the way it’s supposed to....for now

    I won’t repeat the idler disconnect mistake but I don't want phase loss power going to my machines again. The idler motor FLA is 48 at 240V.

    1) Would a solid state overload relay placed before the 3 phase load center protect the idler motor and phase loss?

    2) Is the relay install just hooking up the power in/out and the ground?

    3) Does it matter which way the idler motor spins? I’ve read some conflicting opinions on that.

    Thanks in advance.
    Andy
    Everything you need is already installed and paid for.

    "Conventional wisdom" is to put a(ny) mag-starter's "hold in" contact on anything BUT the "generated leg". Which is actually MORE than stiff enough to hold-in if your rig is worth a damn. Decent idler, reasonable match to the load, a Phase Craft is good enough and will be.

    So do the opposite.

    Put each mag-starter hold-in contact path - or its control transformer - intentionally ON the generated leg.

    Then.... No generated leg, no start.

    Loose the leg or drive it too low? All stop. Inherently.

    No extra players -solid state or otherwise - to go wrong.

    That isn't actually a BAD thing.

    Likewise, no fuses. They can trip but one leg at a time, potentially leaving two hots.

    "COMMON TRIP" circuit breakers, please instead.

    ANY leg misbehaves? ALL are interrupted.

    Want "bells and whistles" on the cheap? Three lights. One each phase. Better yet? Three meters, one each phase.

    Guild THAT lily? Meters for BOTH of Voltage and Current.

    Compamy-funded cremation as a "retired operating engineer" for any rodent as gets into the works and fries his ass to nought but carbonized skeletal carbon trails across the terminals?

    It HAS been done!

    480 VAC input of an ancient 400 Amp Linde Dee Cee stick welder, first time our Union Local held the wake. Poor bugger must have been livin' on beans, ramps, and pickled eggs, the stench his explosive retirement left all up and down the machine-hall.


  7. Likes Hobby Shop liked this post
  8. #5
    Join Date
    Nov 2004
    Location
    Webster Groves, MO
    Posts
    7,985
    Post Thanks / Like
    Likes (Given)
    2077
    Likes (Received)
    3909

    Default

    Quote Originally Posted by thermite View Post
    Likewise, no fuses. They can trip but one leg at a time, potentially leaving two hots.
    I make no claim for this story. It circulated about 30 years ago. A salesman was calling on a plant electrician and noticed some disconnect boxes that looked like they had been dynamited. The electrician explained that they had a pump house in a nearby lake, out in the middle, so it often attracted lightning strikes. Often that would blow a fuse and the motor would burn up single phasing. The electrician said that when a motor came off the line, he wanted it all the way off, so he used fuses with replaceable elements and filled them with gunpowder, which removed all the fuses.

    To be a little more serious, which I have been known to do in rare weak moments, there are phase loss detectors on the market that detect the loss of any phase.

    Bill

  9. Likes johansen liked this post
  10. #6
    Join Date
    Sep 2011
    Country
    UNITED STATES
    State/Province
    Virginia
    Posts
    22,148
    Post Thanks / Like
    Likes (Given)
    7561
    Likes (Received)
    12732

    Default

    Quote Originally Posted by 9100 View Post
    I make no claim for this story. It circulated about 30 years ago. A salesman was calling on a plant electrician and noticed some disconnect boxes that looked like they had been dynamited. The electrician explained that they had a pump house in a nearby lake, out in the middle, so it often attracted lightning strikes. Often that would blow a fuse and the motor would burn up single phasing. The electrician said that when a motor came off the line, he wanted it all the way off, so he used fuses with replaceable elements and filled them with gunpowder, which removed all the fuses.
    Can't call that "common trip" as it is a most UNCommon trip. 'Bout on a par with Capsaicin, USP in K-Y jelly..



    To be a little more serious, which I have been known to do in rare weak moments, there are phase loss detectors on the market that detect the loss of any phase.

    Bill
    Surely there are.

    They call them "burnt up motors".


  11. #7
    Join Date
    Feb 2004
    Location
    peekskill, NY
    Posts
    27,595
    Post Thanks / Like
    Likes (Given)
    0
    Likes (Received)
    6487

    Default

    [QUOTE=thermite;3499777]Can't call that "common trip" as it is a most UNCommon trip. 'Bout on a par with Capsaicin, USP in K-Y jelly..

    Always turn the light on in the bathroom. So you don't grab the ben-gay instead of the KY.

  12. #8
    Join Date
    Nov 2004
    Location
    Webster Groves, MO
    Posts
    7,985
    Post Thanks / Like
    Likes (Given)
    2077
    Likes (Received)
    3909

  13. #9
    Join Date
    Sep 2011
    Country
    UNITED STATES
    State/Province
    Virginia
    Posts
    22,148
    Post Thanks / Like
    Likes (Given)
    7561
    Likes (Received)
    12732

    Default

    Quote Originally Posted by thermite View Post
    Can't call that "common trip" as it is a most UNCommon trip. 'Bout on a par with Capsaicin, USP in K-Y jelly..
    Quote Originally Posted by jim rozen View Post
    Always turn the light on in the bathroom. So you don't grab the ben-gay instead of the KY.
    THIS lot of careless Old F***s?

    More likely to be Loctite, RTV, or Cherry Go-Jo!



    The CHALLENGE is remembering which one goes WHERE, WHEN, and WHY!

  14. #10
    Join Date
    Oct 2004
    Country
    UNITED STATES
    State/Province
    Iowa
    Posts
    3,353
    Post Thanks / Like
    Likes (Given)
    116
    Likes (Received)
    514

    Default

    Just get one of these:

    ICM Product Details - ICM401

    Thirty bucks on Amazon. ICM makes some handy stuff!!!

  15. Likes digger doug liked this post
  16. #11
    Join Date
    Jul 2014
    Location
    MI USA
    Posts
    998
    Post Thanks / Like
    Likes (Given)
    206
    Likes (Received)
    416

    Default Phase Loss Monitor

    Quote Originally Posted by DaveKamp View Post
    Just get one of these:

    ICM Product Details - ICM401

    Thirty bucks on Amazon. ICM makes some handy stuff!!!
    I prefer the ICM450, if you have some panel space to place it. The built in voltage meter is a plus, has line and load side protection, if required. Wide voltage range of power and control circuit voltages, and programmable which makes it handy to adjust for an unbalanced RPC output, and able to change the unbalance limit.

    I have obtained several used units on auctions sites, for a fair price, and they all worked fine. But take a browse at the product downloads, at the bottom of the page, to see if it meets your needs.



    SAF Ω

  17. Likes DaveKamp liked this post
  18. #12
    Join Date
    Dec 2005
    Location
    Langley, B.C.
    Posts
    115
    Post Thanks / Like
    Likes (Given)
    1
    Likes (Received)
    7

    Default

    I am building a (Fitch Williams) 20hp pony start rotary phase convertor, out of spare parts.

    I have a 1/2hp pony flex coupled to the 20hp idler.(outside)

    A Woods xmas-tree remote control outlet powers on an AB PLC (yeah, I know!! But I wanted to program it to do something useful) that spins up the idler, it then applies L1-L2 to the idler, turns off the pony and enables an ICM450(if happy with power quality) closes an output contactor to feed my 240V 3P panel through a volt/ammeter bank.

    I have built 3 banks of 450V capacitors with switches to add/subtract smaller capacitors to tune the idle current and voltage balances while running. They large oil filled ones all have bleed resistors.
    Turning off the shop lights or the Woods remote shuts all 3P down.

    Questions:

    Under what load do I tune the output...largest single load, largest single + compressor, as many loads as it will run?

    How does the icm450 handle the 0-90-180 phase characteristics of a rotary phase converter as opposed to a true 120 degree system?

    I need 575V, will the 3P xformer be noisy with non 120deg power?


    Thanks

  19. #13
    Join Date
    Oct 2017
    Country
    UNITED STATES
    State/Province
    California
    Posts
    1,451
    Post Thanks / Like
    Likes (Given)
    480
    Likes (Received)
    484

    Default

    My RPM had a magnetic starter on all motors, and the large idler's start button wouldn't work unless its pony motor was on.

    I had a contactor powered by the generated leg on the output so as to never feed single phase through to three phase gear.

  20. #14
    Join Date
    Mar 2009
    Country
    UNITED STATES
    State/Province
    California
    Posts
    6,609
    Post Thanks / Like
    Likes (Given)
    131
    Likes (Received)
    1275

    Default

    Quote Originally Posted by Hobby Shop View Post
    I turned the single phase converter power power back on but forgot to flip the idler disconnect switch. The 20hp idler made the awful noise it was supposed to for 1.5 seconds until the power was turned off.

    I usually turn the disconnect off on my little Blanchard grinder but I mustíve forgot. I looked over and seen the white magic smoke rolling out the top of the magnet controller. It still works the way itís supposed to....for now
    magnet controller ?????

    idler disconnect switch ?? Use a 3 conductor contactor or what is called a motor starter. Use a motor starter that has a overload unit that has phase loss and other types of protection.

  21. #15
    Join Date
    Nov 2004
    Location
    Webster Groves, MO
    Posts
    7,985
    Post Thanks / Like
    Likes (Given)
    2077
    Likes (Received)
    3909

    Default

    Quote Originally Posted by weedy64 View Post
    How does the icm450 handle the 0-90-180 phase characteristics of a rotary phase converter as opposed to a true 120 degree system?
    Place three posts in the ground at the points of an equilateral triangle with two on a horizontal line and one above the center of that line at the altitude of the triangle. Stand at the center of the horizontal line and observe the three points. Two will be 180 degrees apart and the third one will be at 90 degrees. Now draw lines from the center of each side to the opposite point and stand at the intersection of these lines. The posts will now be 120 degrees apart. The posts haven't moved, only the vantage point. That is why high leg combined single and three phase systems work. By connecting to the horizontal points and their center point, you have a conventional single phase service. A motor connected to all three points and no ground, either delta or wye with no connection to the common will think it is on regular three phase.

    It is just a matter of how you look at it.

    Bill

  22. Likes atomarc, DaveKamp liked this post
  23. #16
    Join Date
    Mar 2006
    Location
    Vershire, Vermont
    Posts
    2,831
    Post Thanks / Like
    Likes (Given)
    1985
    Likes (Received)
    934

    Default

    Not sure how the OP has his system wired, but doesn't overcurrent protection between the RPC and the load solve this problem?

  24. #17
    Join Date
    Oct 2017
    Country
    UNITED STATES
    State/Province
    California
    Posts
    1,451
    Post Thanks / Like
    Likes (Given)
    480
    Likes (Received)
    484

    Default

    Quote Originally Posted by neilho View Post
    Not sure how the OP has his system wired, but doesn't overcurrent protection between the RPC and the load solve this problem?
    It would prevent things from burning up if sized appropriately, but in my opinion controls should always be interlocked to prevent overload conditions being created from the operator panel.


Tags for this Thread

Bookmarks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •