Previous in Forum: Triple Phase to Split Phase Power Distribution   Next in Forum: Induction Motor Torque Design
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
8 comments
Rate Comments: Nested
shane patel
Participant
India - Member - New Member

Join Date: Mar 2010
Location: india
Posts: 2

Starting Torque

07/13/2010 9:21 AM

i have 3phase, 415V, 50Hz squirrel cage motor.

what is starting torque of the motor?

Motor Nominal RPM is 1500.

current of motor during star connection is 89A.

current of motor delta connection is 52A.

Can anybody have solution?

what is starting torque of motor?
Register to Reply
Interested in this topic? By joining CR4 you can "subscribe" to
this discussion and receive notification when new comments are added.

Good Answers:

These comments received enough positive votes to make them "good answers".

"Almost" Good Answers:

Check out these comments that don't yet have enough votes to be "official" good answers and, if you agree with them, vote them!
Kaisan
Power-User

Join Date: Nov 2009
Posts: 296
Good Answers: 27
#1

Re: starting torque

07/13/2010 9:38 AM

Starting torque will be higher than the normal/nominal torque.

For a very simple explanation, see this article

__________________
 I have no special talent. I am only passionately curious. Albert E
Register to Reply
redfred
Guru
Engineering Fields - Electrical Engineering - Been there, done that. Engineering Fields - Control Engineering - New Member

Join Date: Dec 2008
Location: Long Island NY
Posts: 15600
Good Answers: 981
#3
In reply to #1

Re: starting torque

07/13/2010 10:06 AM

If the motor has an A, B, or E rating it will have a torque curve like what you've shown. These are the most common induction curves but they are not the only ones.

__________________
 "Don't disturb my circles." translation of Archimedes last words
Register to Reply
redfred
Guru
Engineering Fields - Electrical Engineering - Been there, done that. Engineering Fields - Control Engineering - New Member

Join Date: Dec 2008
Location: Long Island NY
Posts: 15600
Good Answers: 981
#2

Re: starting torque

07/13/2010 9:39 AM

Can't tell from the information your giving. You do not indicate which NEMA torque curve your induction motor is designed to follow. Contact the manufacturer for this information.

__________________
 "Don't disturb my circles." translation of Archimedes last words
Register to Reply
2
DaveB
Guru

Join Date: May 2007
Location: Ohio. USA
Posts: 578
Good Answers: 30
#4

Re: starting torque

07/13/2010 10:29 AM

You may be looking for what I have heard referred to as "locked rotor torque".

This link http://www.joliettech.com/speed-torque_characteristics.htm is one of the many that relate motor output characteristics with design parameters. Obviously it would be best to get your question answered by the manufacturer. If this is not possible you may be able to read up on locked rotor torque, and based on your specific motor information you may be able to estimate it. One thing you must know is the NEMA design designation. NEMA's web site is http://www.nema.org/ .

The material I am relating to you is from the US (60 HZ). After reading up on this I would see if there is similar information, such as design designation, in India or other near industrialized countries.

__________________
 Everything I know about opera I learned from Bugs Bunny
Register to Reply Good Answer (Score 2)
No more Good Answers. Go to first "Almost" Good Answer
shane patel
Participant
India - Member - New Member

Join Date: Mar 2010
Location: india
Posts: 2
#5
In reply to #4

Re: starting torque

07/14/2010 12:19 AM

Thank you very much.

but i need more information like equation of starting Torque.

Motor data 37Kw, 415V, 50Hz AC star/delta starting,1500RPM squirrel cage
Register to Reply
kvsridhar
Guru
India - Member - New Member

Join Date: Sep 2009
Location: Temporarily at Ashburn, VA
Posts: 2744
Good Answers: 164
#6
In reply to #5

Re: starting torque

07/14/2010 1:16 AM

Are you the one asking about the slipring motor also (next thread)?

Anyways, best you brush up on motor theory from the cowern papers

__________________
 Nothing worthwhile can ever be taught, it can only be learnt.
Register to Reply
Anonymous Poster
#7

Re: Starting Torque

07/14/2010 1:28 AM

full load torque = (hp*5252)/ (rpm*0.74)........

find the full load torque.

during star connection it s assumed as starting torque= (full load torque / 2.2.....2.3)
Register to Reply Score 1 for Good Answer
No more "Almost" Good Answers.
amarnath.sn
Associate

Join Date: Mar 2009
Posts: 51
Good Answers: 4
#8

Re: Starting Torque

07/14/2010 1:55 AM

Check this thread for a clear understanding.
Register to Reply
Register to Reply
Have a Different Question?
8 comments

Good Answers:

These comments received enough positive votes to make them "good answers".

"Almost" Good Answers:

Check out these comments that don't yet have enough votes to be "official" good answers and, if you agree with them, vote them!
Copy to Clipboard

Users who posted comments:

amarnath.sn (1); Anonymous Poster (1); DaveB (1); Kaisan (1); kvsridhar (1); redfred (2); shane patel (1)

Previous in Forum: Triple Phase to Split Phase Power Distribution   Next in Forum: Induction Motor Torque Design

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 (58 right now)
Show Members
Advertisement