×
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

Schneider SEPAM M20 Protection relay

Schneider SEPAM M20 Protection relay

Schneider SEPAM M20 Protection relay

(OP)
Good day to All,

This is first time I'dealing with this type of relay (I've met ABB, Areva, Siemens) and we have problem during the motor start-up. Since that start time is longer than definite time set for 50/51 the protection trips due to 50/51 during start-up. The real motor start current is greater than threshold of 50/51.
My question is there any possibility to disable 50/51 (or to double like for ABB REM610) during start-up?

Thanks

RE: Schneider SEPAM M20 Protection relay

My first question is why have an OC element set faster than the start-up time? If you wish to have fast trip for say locker rotor condition, then you would either need to use a speed switch or alternatively have the CB/contactor auxilairy contact wired to the relay. Thus on closure program in a delay of x seconds to ensure the OC function is only enabled after the x seconds delay. x seconds needs to be longer than the longest starting time + safety margin.

RE: Schneider SEPAM M20 Protection relay

(OP)
Thanks for replay.
I was not in the project from the beginning and I'm not the one who made configuration file for the relay parameters. In the moment I came 3 out of 4 MV motors have been already running and when we wanted to start the fourth one we faced the issue. And guess what, in those three OC protection is disabled even in the design is mentioned to be enabled . I don't know who did it and why for 4th is not done the same. OK, I can do the same for the last one but in this moment I'm wondering whether is possible to do something in the relay itself. As I already said in ABB protection it's possible to set that protection recognizes start and double the setting for OC.
I agree with you that rewiring the panel would help but it'll be the last option.
Regards,

RE: Schneider SEPAM M20 Protection relay

The normal procedure is to set the instantaneous (50) pickup higher than the motor starting current. Disabling the instantaneous prevents fast protection for faults.

RE: Schneider SEPAM M20 Protection relay

(OP)
jghrist
I agree with you absolutely regarding disabling the protection. In order to set OC higher than the motor start current I need to increase the OC setting at list 50%, that's why I'be been seeking for some other solution.

RE: Schneider SEPAM M20 Protection relay

If the overcurrent pickup is lower than the fault current, then it will provide the necessary fault protection. If the fault current is less than the motor starting current, you have a major motor starting problem.

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