×
Follow Us
Results 1 to 6 of 6

what happens after the 51 element trips?

 Jump to latest post
    #1
  1. Join Date
    Nov 2019
    Posts
    12
    Reputation

    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. 

Name:	main-breaker-a-schematic.jpg 
Views:	56 
Size:	68.6 KB 
ID:	418

  2. #2
  3. Warrengarber's Avatar
    Warrengarber is offline
    If you ignore it, it will fail.
    Seasoned Member Pro Subscriber
    Join Date
    Jul 2017
    Location
    Jacksonville, FL
    Posts
    57
    Reputation
    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:	56 
Size:	68.6 KB 
ID:	418
    Warren Garber
    Have a great day!

  4. #3
  5. Join Date
    Jun 2017
    Posts
    25
    Reputation
    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

  6. #4
  7. GreenHornet is offline
    Riddle me this Batman
    Junior Member
    Join Date
    Jun 2018
    Location
    Vermont
    Posts
    11
    Reputation
    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:	56 
Size:	68.6 KB 
ID:	418
    looks like there is 2 51 relays so like which ever one operates trips the associated 86/lockout which trips the breaker

  8. #5
  9. GreenHornet is offline
    Riddle me this Batman
    Junior Member
    Join Date
    Jun 2018
    Location
    Vermont
    Posts
    11
    Reputation
    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:	56 
Size:	68.6 KB 
ID:	418
    looks like 2 51 relays, each trip their own 86/lockout which trips the breaker

  10. #6
  11. Join Date
    Dec 2017
    Posts
    17
    Reputation
    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.

Subscribe

Login or register to leave a reply!


Share this thread

Related Topics

  1. Ground fault trips at half of setting
    By joenavymctest in forum P&C / Relay Testing Talk
    Replies: 4
    Last Post: November 8, 2017, 03:34 PM

Tags for this Thread



Related Content


Follow us


Explore TestGuy


NETA Certification Training


NICET Electrical Power Testing


Help and Support