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  1. #1
    Join Date
    Nov 2002
    Location
    NJ - WORK IN NYC AREA
    Posts
    1,457

    Question SELECTING A LOCK OUT RELAY

    Need info on how to select a lock out relay?

    Obviously in a control circuit with a LP and HP control, there is a race due to least resistance.

    Can anyone guide me towards a site on how they calculate this relay coil?

    I don't tink its as simple as e = r x i??
    "My hands are for sale"

  2. #2
    Join Date
    Jul 2005
    Location
    south
    Posts
    590
    RBM relays p/n 90-109(24v) and p/n 90-110(230v) are made just for lock-out relay purposes.

  3. #3
    Join Date
    Mar 2007
    Location
    BC,Canada
    Posts
    186
    Not sure how they calculate it but i think the formula is:

    E (voltage)=I (amperage) x Z (impedance)

    High impedance lockout relay coil ends up in series with contactor coil or other load,reduces the current flow enough that the contactor coil won't pull in.

  4. #4
    Join Date
    Jul 2006
    Location
    The Great country of Texas
    Posts
    429
    You can go to Trane and get a "reset relay" out of one of there older recip chillers (CGAA). It is a high impedence coil when put in series with the contactor, it produces enough voltage drop to keep the contactor coil out.
    I personally hate them. I would rather use manual rest switches so I don't have to guess. Old and Lazy!
    "I'm from Texas, what country are you from?"

  5. #5
    Join Date
    Jul 2006
    Location
    The Great country of Texas
    Posts
    429
    One other thing, I am assuming you do not have pump down using the low pressure switch. If so, it will lock out every time it pumps down.
    "I'm from Texas, what country are you from?"

  6. #6
    Join Date
    Nov 2004
    Location
    North Florida/South Georgia
    Posts
    988

    In a pinch

    You can use a 90-380 or a 90-381 depending on your coil voltage.

    We carry a "limited" selection of parts & these relays are perfect because they will dub for a variety of applications.
    All my leon freaked out!

  7. #7
    Join Date
    Nov 2002
    Location
    NJ - WORK IN NYC AREA
    Posts
    1,457

    Thumbs up

    Thanks guys.
    I'll record the relay part numbers. Abco supply should have them.
    "My hands are for sale"

  8. #8
    Join Date
    Jan 2010
    Location
    Central Florida
    Posts
    104
    stickerhead: Do you know any company that makes a manual reset LP switch?
    --------------------------------------------------------------------------------------
    "Give a man a fish he eats for a day. Teach a man to fish he eats for a lifetime"

  9. #9
    Join Date
    Nov 2002
    Location
    NJ - WORK IN NYC AREA
    Posts
    1,457

    Smile

    Johnson Penn

    P20BA SMALLER CONTROL

    P170B LARGER FULLY ADJUSTABLE

    Both fully adjustable.
    "My hands are for sale"

  10. #10
    Join Date
    Apr 2006
    Location
    mechanical room
    Posts
    1,259
    anyone have a wirinng diagram of a lockout ralay, havent seen one in so long, i know the lp, hp and lockout relay n.c. switches are in series, i forgot where the coils are placed in the circuit

  11. #11
    Join Date
    Jan 2010
    Location
    Central Florida
    Posts
    104
    TitleLess posted this picture on another thread. Its also the one I used when I had a brain fart and couldnt remember how to wire one. One thing I am working on tho is if it locks out on LP that it will reset the lockout when the T-Stats shuts off the demand.

    --------------------------------------------------------------------------------------
    "Give a man a fish he eats for a day. Teach a man to fish he eats for a lifetime"

  12. #12
    Join Date
    Mar 2007
    Location
    State of Confusion
    Posts
    1,210
    Quote Originally Posted by stickerhead View Post
    You can go to Trane and get a "reset relay" out of one of there older recip chillers (CGAA). It is a high impedence coil when put in series with the contactor, it produces enough voltage drop to keep the contactor coil out.
    those work good if your looking for a 110 volt relay.

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