52A & B As Applied To Medium Voltage Reclosers

Discussion in 'General Electronics Chat' started by Jsw123, Sep 23, 2014.

  1. Jsw123

    Thread Starter Active Member

    Jun 20, 2009
    I am reading some materials about reclosers, specifically, Cooper/Eaton Form 6 recloser. One thing I have been unable to determine is what a 52 a or b contact is. I looked up "52a Recloser" on Google and found that this applies to multiple manufacturers of reclosers.

    Does anyone know what this term means?

    Here is a quote from Cooper's manual:

    "There are several conditions that will cause the alternate
    and RECLOSER CLOSED LEDs: Failure to Trip, Failure to
    Close, Interrupter Malfunction, and 52a/b Disagreement."
  2. b1u3sf4n09


    May 23, 2014
    From wikipedia:

    Latching state devices[edit]

    Where the state of the operating device can be latched in either state and therefore the normal state is not clearly defined a different style of contact definitions may be used.

    Form A contact[edit]
    A Form A contact is closed when the operating device main contact or mechanism is closed or latched. Its function is logically equal to the device it resides on.

    Form B contact[edit]
    A Form B contact is a contact that is closed when the operating device main contacts or mechanism is open or latched open. Its function is logically inverted to the device it resides on.

    I don't know if this necessarily applies here, but that is my two cents.
  3. Jsw123

    Thread Starter Active Member

    Jun 20, 2009
    IEEE Device function number 52 is a circuit breaker. However, I am not sure if this is applicable.
  4. subtech

    AAC Fanatic!

    Nov 21, 2006
    b1u has got it right. The "a" contact is closed when the breaker (or recloser in your case) main contacts are closed.
    The "b" contact is opposite of this.
    IEEE device function number 52 is a circuit breaker, and more accurately stated it is an AC circuit breaker.

    It is common in larger, medium and high voltage electrical devices such as breakers to have multiple auxiliary switches (52a and 52b)
    that operate along with the main mechanical linkages of the device. These are typically used in control and protective
    schemes, as well as for reporting status of the device. Where I work, it is standard to use a 52a contact to report
    the open/close state of a circuit breaker to the control center.
    b1u3sf4n09 likes this.
  5. alfacliff

    Well-Known Member

    Dec 13, 2013
    around here, reclosers are used on power lines to trip under overcurrent, then reclose after a time set internally. the a and b refer to no and nc contacts in the recloser.
    b1u3sf4n09 likes this.
  6. b1u3sf4n09


    May 23, 2014
    Thank you for elaborating, subtech and alfacliff. We use Form A, B, and C (NO & NC) switches in our actuators, but our ratings do not exceed 250VAC. I wasn't sure if the logic carried over to medium and high voltage, but I am happy that it does. It seems so rare in industry that this occurs.