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  1. #1
    BruceC is offline Aluminum
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    I have a three phase 3/4 hp delta motor (for a 12" delta wood lathe) which looks pretty unused new but I assume is old because it does not seem to have a ground wire. Does it creat a affective ground if I attach the ground wire (from the cord going to the wall outlet) to the motor housing? Also, do I need to know which of the three power lines are L1 L2 L3 or are they interchangable?
    Thanks, Bruce

  2. #2
    tnmgcarbide's Avatar
    tnmgcarbide is offline Titanium
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    hook them all up, check direction of rotation.
    if you need to reverse it, swap any 2 phases .
    if you're a stickler for grounded motors..i'd
    just find any screw or nut available for a lug.

  3. #3
    Jon_Spear is offline Hot Rolled
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    Yes, what tnmgcarbide said.

    If you're concerned about grounding and safety, use a multimeter to check the resistance between any of the 3 leads and the motor housing. There should not be an electrical connection.

  4. #4
    HelicalCut is offline Stainless
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    Hook the ground to the motor case if that is the only point where there will be power on the machine. When done measure the resistance between the ground pin on the plug and the machine frame, it should be < 2 ohms

  5. #5
    BruceC is offline Aluminum
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    Thank you all for the responses and explanations. I would like to ask further questions.

    After the “line” passes from the wall outlet it goes through an “A-c full voltage Magnetic starter size “OO” three pole”.

    Cutler-Hammer
    NEMS SIZE OO
    Max 3 Ph Rating

    9AMP
    115V--------3/4HP
    200/230V----1.5HP
    460/575V----2HP

    This starter has “start”, “stop”, and “R” (reset?) buttons on it. It appears to me that the starter was added.
    Then the “line” goes to a push button start/stop switch.

    1) How do I know if this is the correct starter for this motor? The best I can tell, the heaters are rated 4.92-5.15Amps while the motor is 2.8/1.4-3.4/1.7Amps (208-220/440V). Do I need to buy different heaters?
    2) Is 14/4 the correct wire to be using for this?
    3) How do the start/stop buttons of the starter work with the other stop/start button switch? The starter is in poor location. It would be difficult to use this as the on/off switch let alone to quickly shut the machine off in an emergency. Do I use the starter to turn on and off the machine?

    Thanks again,
    Bruce

  6. #6
    tnmgcarbide's Avatar
    tnmgcarbide is offline Titanium
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    This starter has “start”, “stop”, and “R” (reset?) buttons on it. It appears to me that the starter was added.
    Then the “line” goes to a push button start/stop switch. "

    that -R- sounds like reverse.

    the motor heaters should be ok. 3/4hp motors
    are often run without overload protection.
    both my 3ph bandsaws are straight wired , without
    heaters. on a 12" or larger geared metal lathe , with its
    significant starting torque....yes, but on
    a wood lathe...probably not critical.

    14 ga wire is plenty for that motor at 220v.

    whichever switch is closest will stop the machine.

  7. #7
    JL Sargent is offline Titanium
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    Bruce, do you have 3 phase power for this machine?

  8. #8
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    Yes, I was going to ask the same question...normally 3ph is not found in the wall unless you put it there! (Could be lucky and already have it though).

    To properly use the Motor Starter, you'll likely need a wiring setup like the one below. An important thing is that the coil voltage matches whatever you are powering the "ladder" with. I am purely guessing at 115vac but it could also be 24vac, or 24vdc or something else. If you check the coil on the motor starter (the "O" symbol below) it usually has this information listed. The -] [- is a normally open contact that the motor starter will have, essentially as a 4th pole. The same symbol with a slash thru -]/[- it is a normally closed contact for the overload heaters. Generally the principle here is that things that "start" the motor are in parallel, and things tht "stop" the motor are in series with the coil.



    PS: Either I can't write straight or can't scan straight...not quite sure which

  9. #9
    tsmartin_98 is offline Aluminum
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    Bruce:

    1) Starter size is fine. I think the heaters are oversized and would get a set closer to the motor nameplate rating. Your motor could get much hotter than "normal" before tripping the OL.
    Is this 240 or 480?

    2) Wire size is fine.

    3) Is this C-H starter a reversing starter? If so the "R" could be for reverse or "RESET" for the OL. It sounds like the second start/stop station is handling full motor voltage. If so, that would worry me.

    TS

  10. #10
    BruceC is offline Aluminum
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    Thanks for the responses.

    Matt, thank you for the diagram. I will have to study it more as I don’t understand it but I would like to. What is “coil” referring to? And what is meant by “ladder”. (Yes, I am real behind the curve on this.)

    I am using a rotary phase converter powered by 220V to get 3 phases.

    The starter may be over kill for this ¾ motor and maybe I should just take it off the machine.

    The second start/stop switch runs at full voltage. It seems to me that there should be a low voltage remote start\stop switch (like the one, or instead of the one, on the starter) located in a user friendly place. I assume this switch would activate the electro magnet which activates the full voltage switch in the starter. Isn’t this how the starter works?

    Is there a correct direction of current flow through the starter or can the current come in from either end?

    Thanks

  11. #11
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    The coil is the electromagnetic "coil" (of wire) which, when energized, closes the relay contacts.

    Ladder is just a terminology for this style of "logic"...can sprout into literally pages of "rungs" for complicated automation. This one just has a single "rung" or horizontal line.

    I assume you have an AC-voltage starter, again, check the printing, it should state exactly what it requires on the face....and if it doesn't, you should contact the manufacturer or discard it in favor of one with better markings. That said, an AC voltage starter cannot have a "polarity", merely the circuit is completed when the left vertical line in the schematic and the right vertical line in the schematic have continuity.

  12. #12
    tsmartin_98 is offline Aluminum
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    BruceC:

    Any chance of seeing some pics of your set up? Seeing what you are working with would be a great help.

    TS

  13. #13
    BruceC is offline Aluminum
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    Here are pics of the starter, starter cover on/off/R buttons, full voltage switch, and,I think, an example of a low voltage switch.






    I am guessing that I want to use the starter but with a low voltage switch (in a user friendy location) instead of the full voltage switch.
    Thanks for your input.

  14. #14
    BruceC is offline Aluminum
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    What is the funtion of the red, yellow, and black wires on the starter? These are not L1,L2,L3 but seem to be part of the starter itself.
    Thanks.

  15. #15
    tsmartin_98 is offline Aluminum
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    From what I see the "R" is a reset button to reset the OL which is the white button on the far left.

    The red, yellow and black look like the control wires which when hooked up like on Matts sketch turns the starter on or off. You'd need to trace those wires to find out how they are connected to the start/stop buttons. Or maybe a visit to C-H website might have a diagram of how it hooks up.
    Edit: Followed my own advice and went to C-H site. This starter isn't shown. Possibly all the "Citation" series are discontinued by now. There are wiring diagrams for 3 wire control but they don't use a color code. I have some old C-H catalogs at work. Maybe they will tell which color goes where.

    I'm guessing, that if you're using 220 the starter coil is also 220. You'll need to check that. The voltage should be printed on the coil in plain sight. If it is a 220 coil, you'd need to swap it out with a 110 volt coil to use 110. And, someone correct me if I'm wrong, I believe the C-H 00 series starters are obsolete.

    Other wise your stuck with full voltage unless you want to use an interposing 110 relay. That would be more "stuff" in the control box.

    TS

  16. #16
    BruceC is offline Aluminum
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    I took the starter apart a little bit to try and figure out how it works and understand what people have been saying. I think I understand how the "points" close when the coil is activated and that they stay closed until the stop switch is opened.

    I don't understand how the coil is 220V with seemingly only one wire going to it and one leaving it. And I don't understand why the wire living the coil, passing through an overload device (I think but I can't see it.) ends up at L2. It seems like for 220V the coil would need two wires going in and two wires leaving.

    I have spent 2 hours trying to scan clear wiring diagram but have been unable to.

  17. #17
    tsmartin_98 is offline Aluminum
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    I can understand your confusion. We all had to go through that while learning.

    What you need to remember is that you are dealing with 3 phase not single phase. Each leg is 220 not 110 like your house has. That's why you only have one wire instead of two.

    Here's a link to a drawing that I think is what you have drawn .... only clearer.

    http://wiki.owwm.com/ow.asp?MotorStarterWiringDiagrams

    Page down to the 3 ph starter/3 ph motor drawing.


    The "O" on the left side of the main contacts is the coil, the other set of contacts to the left of the coil is the holding contacts and the contacts below the coil with the slash through it is the OL contact that will drop out the coil when the OL trips.

    Compare this pic to what you have and I'll bet it will make sense.

    TS

  18. #18
    BruceC is offline Aluminum
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    Thank you TS. That is a diagram I attempted to draw but yours is much clearer. Things are making more sense.

    I had mentioned in previous posts wanting a remote, low voltage switch but the web site you gave explains that a transformer is needed to do this. The starter I have doesn’t have a transformer so I think I will only try to set up a remote start/stop switch using two switches such as in the last picture I posted above. I think this is what this switch is for. Do you know of any reason not to change out the switch on the starter to a remote one using switches like in the picture?

    Thanks for all your input.

    Bruce

  19. #19
    tnmgcarbide's Avatar
    tnmgcarbide is offline Titanium
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    Each leg is 220 not 110 like your house has. That's why you only have one wire instead of two."

    hmmm.... 1 wire to ground will be 110, it takes
    2 wires to make 220. each individual leg is 110.

  20. #20
    Mike W is offline Stainless
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    Bruce, I redid my Clausing with a 24 volt contactor coil and used a 220 to 24 volt transformer from MSC. I like the low voltage wiring to the start and stop switches. I use a small relay that latches in once the start switch is pushed.

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