Analysing this easy 2 relay circuit .

Discussion in 'General Electronics Chat' started by LETITROLL, Oct 2, 2014.

  1. LETITROLL

    Thread Starter Member

    Oct 9, 2013
    218
    2
    HI all .


    I have been trying to simulate this circuit , but the problem is not the cimulation but how it actually works .

    As you can see in the circuit , there is 2 KM contactors 1 and 2 , each one has a coil and 1 switch ( NC i guess) that changes its state when the coil is fed .

    First i don't know what does the triangle symbol means ?

    Does the two contactors have two different switches one NC and another NO ?

    This circuit is meant to block the rotation to one sens until the motor is stopped, how can this circuit do that , i mean what is the logic ?
     
  2. alfacliff

    Well-Known Member

    Dec 13, 2013
    2,449
    428
    its a reversing relay. the triangle means that the two contactors are mechanicly interlocked so they can only turn on one at a time. the double circle thing between the contacts and the relays is a "plugging switch" that senses zero rotation of the motor so it can be reversed.
     
  3. LETITROLL

    Thread Starter Member

    Oct 9, 2013
    218
    2
    Tanks , i have figured out how it works after a while , the double circle symbol is just a step down transformer .
     
  4. MaxHeadRoom

    Expert

    Jul 18, 2013
    10,565
    2,379
    Correct, also you may notice, apart from the European symbols, the logic progresses from a top rail downward, as opposed to N.A. that uses vertical power rail and the logic progresses across the page from left to right.
    http://static.schneider-electric.us/docs/Machine Control/0140CT9201.pdf
    http://ecat.moeller.net/flip-cat/?edition=WMERS
    Max.
     
  5. LETITROLL

    Thread Starter Member

    Oct 9, 2013
    218
    2
    Thanks max , your links are very good .

    Ill be very happy to share with you the rs logix along with the emulator .

    As for the design i notice the difference between NA and EU , NA schems are more ladder oriented .
     
    Last edited: Oct 2, 2014
  6. MaxHeadRoom

    Expert

    Jul 18, 2013
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    Thanks, I have RSlogix but I usually plug the program into a PLC for debug, but don't do much AB any more, mostly Mitsubishi.
    On a NA EU related note, I see that N.A. code has adopted the European version of a previous wire colour difference, namely the conductor colour of one that originates outside of an enclosure and may be live, previously it was Yellow for N.A. and Orange for Europe, now Orange for both.
    Max.
     
  7. LETITROLL

    Thread Starter Member

    Oct 9, 2013
    218
    2
    Can i use the rs ladder diagrams to program a mitsubishi plc for example
     
  8. MaxHeadRoom

    Expert

    Jul 18, 2013
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    No they have completely different instruction sets and are incompatible with each other unfortunately.
    All PLC's pretty much have their own software and instructions although similar in some respects, do not work together.
    Max.
     
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