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what happens after the 51 element trips?

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    what happens after the 51 element trips?

    Given a circuit breaker schematic what happens after the 51 element trips?

    A) Trip coil energizes and opens the breaker
    B) 86-1 contacts close
    C) 86-1 and 86-2 relay operates
    D) 86-1 relay operates
    E) 86-2 relay operates

    its hard to read this diagram can anyone help?

    Click image for larger version. 

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    It is really hard to see but the two 50/51 elements in the SR relay operate and next will operate the 86-1 and the 86-2 lock out relays. The two lock out relays will then energize the trip coil (TC). So I think the answer should be C.




    Quote Originally Posted by mbaxter1 View Post
    Given a circuit breaker schematic what happens after the 51 element trips?

    A) Trip coil energizes and opens the breaker
    B) 86-1 contacts close
    C) 86-1 and 86-2 relay operates
    D) 86-1 relay operates
    E) 86-2 relay operates

    its hard to read this diagram can anyone help?

    Click image for larger version. 

Name:	main-breaker-a-schematic.jpg 
Views:	156 
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ID:	418
    Warren Garber
    Have a great day!

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    Quote Originally Posted by Warrengarber View Post
    It is really hard to see but the two 50/51 elements in the SR relay operate and next will operate the 86-1 and the 86-2 lock out relays. The two lock out relays will then energize the trip coil (TC). So I think the answer should be C.
    This is what i see too, though there are some NO and NC contacts before and after the 86-1 and the 86-2 lock out relays which are not labeled. Depending on which state they are in could change the answer

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    Quote Originally Posted by mbaxter1 View Post
    Given a circuit breaker schematic what happens after the 51 element trips?

    A) Trip coil energizes and opens the breaker
    B) 86-1 contacts close
    C) 86-1 and 86-2 relay operates
    D) 86-1 relay operates
    E) 86-2 relay operates

    its hard to read this diagram can anyone help?

    Click image for larger version. 

Name:	main-breaker-a-schematic.jpg 
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ID:	418
    looks like there is 2 51 relays so like which ever one operates trips the associated 86/lockout which trips the breaker

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    Quote Originally Posted by mbaxter1 View Post
    Given a circuit breaker schematic what happens after the 51 element trips?

    A) Trip coil energizes and opens the breaker
    B) 86-1 contacts close
    C) 86-1 and 86-2 relay operates
    D) 86-1 relay operates
    E) 86-2 relay operates

    its hard to read this diagram can anyone help?

    Click image for larger version. 

Name:	main-breaker-a-schematic.jpg 
Views:	156 
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ID:	418
    looks like 2 51 relays, each trip their own 86/lockout which trips the breaker

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    Quote Originally Posted by mbaxter1 View Post
    Given a circuit breaker schematic what happens after the 51 element trips?

    A) Trip coil energizes and opens the breaker
    B) 86-1 contacts close
    C) 86-1 and 86-2 relay operates
    D) 86-1 relay operates
    E) 86-2 relay operates

    its hard to read this diagram can anyone help?

    A)Trip coil energizes and opens the breaker

    B and D are correct! Relay 86-1 will operate due to the closed contact and will energize TC.

    C and E are wrong. Relay 86-2 will never operate due to the open contact.

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  13. keatigp is offline Junior Member Pro Subscriber
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    Quote Originally Posted by Nick1234 View Post
    This is what i see too, though there are some NO and NC contacts before and after the 86-1 and the 86-2 lock out relays which are not labeled. Depending on which state they are in could change the answer
    The normally closed contacts surrounding a lockout coil in most cases are contacts that open on the operation of a lockout to protect its own coil.

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    Quote Originally Posted by mbaxter1 View Post
    Given a circuit breaker schematic what happens after the 51 element trips?

    A) Trip coil energizes and opens the breaker
    B) 86-1 contacts close
    C) 86-1 and 86-2 relay operates
    D) 86-1 relay operates
    E) 86-2 relay operates

    its hard to read this diagram can anyone help?

    Click image for larger version. 

Name:	main-breaker-a-schematic.jpg 
Views:	156 
Size:	68.6 KB 
ID:	418
    D) 86-1 relay operates
    Last edited by Izeldeen; January 27, 2022 at 11:38 PM.

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  17. hmathis1976 is offline Junior Member Pro Subscriber
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    Please Review 51 Element Trips

    If you review the schematic there are two elements that are mapped to two N.O contacts which upon exceeding the threshold the relay should close both outputs which in turn will roll both 86-1 and 86-2 LO Relays. Please Advise.

    Quote Originally Posted by mbaxter1 View Post
    Given a circuit breaker schematic what happens after the 51 element trips?

    A) Trip coil energizes and opens the breaker
    B) 86-1 contacts close
    C) 86-1 and 86-2 relay operates
    D) 86-1 relay operates
    E) 86-2 relay operates

    its hard to read this diagram can anyone help?

    Click image for larger version. 

Name:	main-breaker-a-schematic.jpg 
Views:	156 
Size:	68.6 KB 
ID:	418

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    Quote Originally Posted by mbaxter1 View Post
    Given a circuit breaker schematic what happens after the 51 element trips?

    A) Trip coil energizes and opens the breaker
    B) 86-1 contacts close
    C) 86-1 and 86-2 relay operates
    D) 86-1 relay operates
    E) 86-2 relay operates

    its hard to read this diagram can anyone help?

    Click image for larger version. 

Name:	main-breaker-a-schematic.jpg 
Views:	156 
Size:	68.6 KB 
ID:	418
    When the relay operates on a 51 function both the 86-1 & 86-2 will get 65V+. The coil of the 86-2 will not be energized since there will be no negative voltage going to it with the contact points below are still open. The question is "after" the function asserts, so the very next thing that happens is the 86-1 coil operates. The trip coil would be after that.

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