×
INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS

Log In

Come Join Us!

Are you an
Engineering professional?
Join Eng-Tips Forums!
  • Talk With Other Members
  • Be Notified Of Responses
    To Your Posts
  • Keyword Search
  • One-Click Access To Your
    Favorite Forums
  • Automated Signatures
    On Your Posts
  • Best Of All, It's Free!
  • Students Click Here

*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.

Students Click Here

Jobs

Multilin 369 Fail Safe vs Non Fail Safe

Multilin 369 Fail Safe vs Non Fail Safe

Multilin 369 Fail Safe vs Non Fail Safe

(OP)
Hello Everyone!

I am looking to upgrade my Multilin 269+ motor protection relay with the newer Multilin 369 relay. While analyzing the drawings, I observed that presently, the 269+ is wired up such that the normally closed contacts 30 and 31 feed the motor main contactor (M).

I am unsure if this is programmed to be a fail safe (FS) or a non fail safe (NFS), so I do not know what will happen on loss of control power. However, I do know that if there is an undervoltage condition, the relay will trip out.

I am not certain what I should assign as my relay trip contacts in 369. From the user manual, I understand that a FS contact changes state when power is lost to the relay, while a NFS contact does not.

So, how do I choose my trip relay contacts? NO or NC, which ones should be FS or NFS?

Also, if say I assign the NC trip contact as FS, then will it change state when powered up?

RE: Multilin 369 Fail Safe vs Non Fail Safe

A FS relay is powered-on when there are no trips. Then, it is powered-off if there is a trip or if the power fails. Your present relay uses a closed contact in the circuit. So, use FS and NO contact or use NFS and NC contact. The choice really depends on your particular application.

Red Flag This Post

Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.

Red Flag Submitted

Thank you for helping keep Eng-Tips Forums free from inappropriate posts.
The Eng-Tips staff will check this out and take appropriate action.

Reply To This Thread

Posting in the Eng-Tips forums is a member-only feature.

Click Here to join Eng-Tips and talk with other members!


Resources