Previous in Forum: Who Know Where To Buy Good RF Power Capacitor Like Morgan But In Cheaper?   Next in Forum: Synchronism Check Relay settings
Close

Comments Format:






Change Mode
Close

Subscribe to Discussion:

CR4 allows you to "subscribe" to a discussion
so that you can be notified of new comments to
the discussion via email.

Close

Rating Vote:







Add Vote
7 comments
Rate Comments: Nested
sonsan
Member

Join Date: Mar 2011
Posts: 5

Circuit Breaker Symbols and Ratings

12/03/2012 5:44 PM

Hello,

I have a single line diagram which has circuit breaker symbol and ratings as

Can someone please tell me what the numbers 125, 63 and 40A mean? This is a breaker in a motor starter circuit for a 22kW motor @415Volts, about 39Amps FLA.

Thanks.
Register to Reply
Interested in this topic? By joining CR4 you can "subscribe" to
this discussion and receive notification when new comments are added.
Crabtree
Guru

Join Date: Jul 2007
Location: Commissariat de Police, Nouvions, occupied France, 1942.
Posts: 2599
Good Answers: 77
#1

Re: Circuit breaker rating

12/03/2012 5:50 PM

When I went to study them, those things were the maximum continuous current before the thing would operate, Boss. I have no idea if it has changed since then.

__________________
 Good moaning!
Register to Reply
arifkunnath
Commentator

Join Date: Oct 2011
Posts: 95
#2

Re: Circuit Breaker Symbols and Ratings

12/04/2012 1:02 AM

I think MCCB is 125A / 63A frame with set to break at 40A

or it can withstand a staring current up to 125A with running current with standing capacity of 40A.
Register to Reply
iftikhar129
Commentator

Join Date: Dec 2011
Posts: 67
#3

Re: Circuit Breaker Symbols and Ratings

12/04/2012 1:06 AM

consult data sheet......
Register to Reply
debata07
Power-User

Join Date: Nov 2011
Posts: 131
Good Answers: 5
#4

Re: Circuit Breaker Symbols and Ratings

12/04/2012 11:11 PM

The circuit breaker belongs to frame size of maximum 125A, but its nominal current or rated current is 63A and its overload setting is kept at 40A.
Register to Reply
AHMAD REZA CHANGIZ
Active Contributor
Iran - Member - New Member

Join Date: Nov 2012
Location: IRAN -
Posts: 14
Good Answers: 1
#5

Re: Circuit Breaker Symbols and Ratings

12/06/2012 1:26 AM

If you have a direct motor starter -it has a main circuit breaker MCCB 125 amp and 63 amp contactor and an over current relay 40-63 amp that sets on 40 amps.

__________________
 we all switch to perfection
Register to Reply Off Topic (Score 5)
AHMAD REZA CHANGIZ
Active Contributor
Iran - Member - New Member

Join Date: Nov 2012
Location: IRAN -
Posts: 14
Good Answers: 1
#6

Re: Circuit Breaker Symbols and Ratings

12/06/2012 1:36 AM

If you have a direct motor starter it has a main circuit breaker 125 amp MCCB and 63 amp contactor and 40-63 A over current relay that set on 40 A.

__________________
 we all switch to perfection
Register to Reply
Awf65
Active Contributor

Join Date: Nov 2012
Posts: 10
#7

Re: Circuit Breaker Symbols and Ratings

12/09/2012 11:50 PM

The motor starting current usually 5 times the running current of the motor. So the motor circuit breaker as shown above, 125 is the Amps frame for starting current and the 63 is the Amps frame of the running current of the motor while the 40 Amps is the trip current settings of the breaker. AF/AT.
Register to Reply
Register to Reply
Have a Different Question?
7 comments
Copy to Clipboard

Users who posted comments:

AHMAD REZA CHANGIZ (2); arifkunnath (1); Awf65 (1); Crabtree (1); debata07 (1); iftikhar129 (1)

Previous in Forum: Who Know Where To Buy Good RF Power Capacitor Like Morgan But In Cheaper?   Next in Forum: Synchronism Check Relay settings

Advertisement

Got Something to Say?
Ask a Question
Start a Discussion

Search this Forum
Electrical Engineering:
Go

CR4 Sections
Aerospace
BioMech & BioMed
Chemical & Material Science
Civil Engineering
Communications & Electronics
Education and Engineering Careers
Electrical Engineering
General Discussion
Instrumentation
Manufacturing
Mechanical Engineering
New Technologies & Research
Software & Programming
Sustainable Engineering
Transportation

Site Directories
Forum Directory
Blog Directory
User Group Directory
RSS Feeds

CR4 Rules of Conduct
CR4 FAQ
Site Glossary

Who's Online (73 right now)
Show Members
Advertisement