Go Back   Electricians Forum | Electrical Advice Forum | An electrical forum for electricians in the UK > Electrical Forum, Electrical Talk Forum > Commercial and Industrial Electrical

Notices

Login or register (for free!) to remove these ads.

51 & 49 function relay -


Reply
 
LinkBack Thread Tools Display Modes
Old 12-01-2009   #1 (permalink)
Tran_Lap
Junior Member
 

Join Date: Jan 2009
Posts: 2
Thanks: 1
Thanked 0 Times in 0 Posts
Default 51 & 49 function relay

Hi all

New to the forum, can everyone help me to explain the difference between 51 and 49 function relay incase motor protection.

Thank you
__________________
------------------
You can do, Do it now
Tran_Lap is offline  
Digg this Post!Add Post to del.icio.usBookmark Post in TechnoratiFurl this Post!
Reply With Quote
Old 12-01-2009   #2 (permalink)
mrloy99
Senior Member
 
mrloy99's Avatar
 

Join Date: Dec 2008
Posts: 367
Thanks: 7
Thanked 16 Times in 16 Posts
Default Re: 51 & 49 function relay

Quote:
Originally Posted by Tran_Lap View Post
Hi all

New to the forum, can everyone help me to explain the difference between 51 and 49 function relay incase motor protection.

Thank you
tooo vague
mrloy99 is offline  
Digg this Post!Add Post to del.icio.usBookmark Post in TechnoratiFurl this Post!
Reply With Quote
Old 12-01-2009   #3 (permalink)
DanBrown
Senior Member
 

Join Date: Dec 2007
Posts: 196
Thanks: 10
Thanked 7 Times in 7 Posts
Exclamation Re: 51 & 49 function relay

What do you mean exactly 51 & 49??, is this on the contactor overload??
DanBrown is offline  
Digg this Post!Add Post to del.icio.usBookmark Post in TechnoratiFurl this Post!
Reply With Quote
Old 12-01-2009   #4 (permalink)
Lenny
Moderator
 
Lenny's Avatar
 

Join Date: Dec 2008
Location: South Wales
Posts: 3,335
Thanks: 146
Thanked 542 Times in 475 Posts
Default Re: 51 & 49 function relay

Hey.

With regard to motor protection there are a number of different relays that have different jobs.

Function 49 is overload protection
Function 51 is locked rotor protection.

There are lots of others - 50 = phase fault protection
50N = earth fault protection
50 + 51N = Time overcurrent with thermal in built.

You can also get harmonic protection etc etc

Hope this helps

Cheers

Last edited by Lenny; 12-01-2009 at 07:56 PM..
Lenny is offline  
Digg this Post!Add Post to del.icio.usBookmark Post in TechnoratiFurl this Post!
Reply With Quote
The Following User Says Thank You to Lenny For This Useful Post:
Tran_Lap (07-05-2009)
Old 13-01-2009   #5 (permalink)
Tran_Lap
Junior Member
 

Join Date: Jan 2009
Posts: 2
Thanks: 1
Thanked 0 Times in 0 Posts
Default Re: 51 & 49 function relay

my understanding 51 using for overcurrent protection, but the reason of overcurrent is overload, 49 is thermal relay and the reason is overload too. So, can I use one of them for overload protection? when do I use both ?

thank you
__________________
------------------
You can do, Do it now

Last edited by Tran_Lap; 13-01-2009 at 05:18 AM..
Tran_Lap is offline  
Digg this Post!Add Post to del.icio.usBookmark Post in TechnoratiFurl this Post!
Reply With Quote
Reply
  

Bookmarks



Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On


Similar Threads
Thread Thread Starter Forum Replies Last Post
Trying to find a relay Dorian.Fabre Electrical Forum | General Electrical Forum 4 18-10-2009 08:21 AM
a Synchronism check relay bejoyengineer Commercial and Industrial Electrical 1 29-03-2009 04:35 PM
low voltage relay? jimbo198966 Commercial and Industrial Electrical 4 10-03-2009 01:53 PM
please explain relay settings ericsson Electrical Forum | General Electrical Forum 3 15-01-2009 07:01 PM



Powered by vBulletin® Version 3.8.4
Copyright ©2000 - 2010, Jelsoft Enterprises Ltd.
SEO by vBSEO 3.0.0

u.m Network: Contractor Forum | Tilers Forum | Plastering Forum | Flooring Forum | Plumbing Forum |
(c) 2008 Electricians Forum | Electrical Forum | Electrical Advice | Electricians Jobs | A forum for electricians in the UK