Previous in Forum: Motor Thermal Time Constants   Next in Forum: Overload vs Short Circuit
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
9 comments
Rate Comments: Nested
coolyaar
Power-User

Join Date: Jul 2011
Posts: 286
Good Answers: 1

Starting Time vs Stall Time

06/03/2012 4:50 PM

what is the difference between starting time and the cold stall time of a 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".
Tornado
Guru
Technical Fields - Technical Writing - New Member Engineering Fields - Piping Design Engineering - New Member

Join Date: May 2009
Location: Richland, WA, USA
Posts: 21017
Good Answers: 795
#1

Re: starting time vs stall time

06/03/2012 5:01 PM

Maybe a factor of around 2; exercise for reader to figure out in which direction, and why.

(Hint: Think about what the motor is doing in each case.)

__________________
 In vino veritas; in cervisia carmen; in aqua E. coli.
Register to Reply
coolyaar
Power-User

Join Date: Jul 2011
Posts: 286
Good Answers: 1
#2
In reply to #1

Re: starting time vs stall time

06/03/2012 5:16 PM

Well i think that stall times should be less because we want stall conditions to clear more fastly and want to give motors enough time to start up .what do you think?
Register to Reply
Tornado
Guru
Technical Fields - Technical Writing - New Member Engineering Fields - Piping Design Engineering - New Member

Join Date: May 2009
Location: Richland, WA, USA
Posts: 21017
Good Answers: 795
#4
In reply to #2

Re: starting time vs stall time

06/03/2012 5:40 PM

Your conclusion is correct; your reasoning is on the right track but not complete.

(I will wait a while before elaborating.)

__________________
 In vino veritas; in cervisia carmen; in aqua E. coli.
Register to Reply
coolyaar
Power-User

Join Date: Jul 2011
Posts: 286
Good Answers: 1
#5
In reply to #4

Re: starting time vs stall time

06/03/2012 5:50 PM

Well i have no other point in my mind to clear the idea completely
Register to Reply
lyn
Guru

Join Date: Oct 2008
Posts: 42355
Good Answers: 1693
#6
In reply to #5

Re: starting time vs stall time

06/03/2012 6:23 PM

How to Search the Internet
Register to Reply
nobodysomebody47
Power-User

Join Date: Nov 2011
Posts: 171
Good Answers: 1
#3

Re: starting time vs stall time

06/03/2012 5:18 PM

see this

Calculating Motor Start Time & Stall time
Register to Reply
2
electricalexpert65
Guru

Join Date: Oct 2009
Posts: 2061
Good Answers: 169
#7

Re: Starting Time vs Stall Time

06/04/2012 12:00 PM

Can't you figure out?

Starting time is the time taken by the motor to bring its rotor from rest to rotation at rated speed, under defined conditions of starting. When a motor is in starting mode, the rotor actually starts rotating & thus back emf builds up. Thus the starting current gradually reduces from its intial locked rotor current value.

Whereas, when a motor stalls (even when it is started from cold), the rotor doesn't rotate at all and thus the full locked rotor current continues to flow in the motor causing possible stator damage and/or rotor damage. Thus, as rightly observed by you, the cold stall withstand time is much lesser than the starting time.
Register to Reply Good Answer (Score 2)
No more Good Answers.
pnaban
Guru

Join Date: Jun 2010
Location: srilanka
Posts: 2725
Good Answers: 5
#8

Re: Starting Time vs Stall Time

06/05/2012 1:03 AM

Starting time depends on method of starting(DOL,S/D,AT,VFD etc) as well as connected load. Stalling time depends on connected load.

__________________
 pnaban
Register to Reply
PWSlack
Guru
United Kingdom - Member - Indeterminate Engineering Fields - Control Engineering - New Member

Join Date: Jan 2007
Location: In the bothy, 7 chains down the line from Dodman's Lane level crossing, in the nation formerly known as Great Britain. Kettle's on.
Posts: 32175
Good Answers: 839
#9

Re: Starting Time vs Stall Time

06/11/2012 4:09 AM

The inertia of whatever it is turning.

__________________
 "Did you get my e-mail?" - "The biggest problem in communication is the illusion that it has taken place" - George Bernard Shaw, 1856
Register to Reply
Register to Reply
Have a Different Question?
9 comments

Good Answers:

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

Users who posted comments:

coolyaar (2); electricalexpert65 (1); lyn (1); nobodysomebody47 (1); pnaban (1); PWSlack (1); Tornado (2)

Previous in Forum: Motor Thermal Time Constants   Next in Forum: Overload vs Short Circuit

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 (91 right now)
Show Members
Advertisement