Relationship: Locked rotor amp and full load amp
Relationship: Locked rotor amp and full load amp
(OP)
What's the relationshop between Locked rotor amp and full load amp?
INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS Come Join Us!Are you an
Engineering professional? Join Eng-Tips Forums!
*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail. Posting GuidelinesJobs |
Relationship: Locked rotor amp and full load amp
|
Relationship: Locked rotor amp and full load ampRelationship: Locked rotor amp and full load amp(OP)
What's the relationshop between Locked rotor amp and full load amp?
|
ResourcesWhat is rapid injection molding? For engineers working with tight product design timelines, rapid injection molding can be a critical tool for prototyping and testing functional models. Download Now
The world has changed considerably since the 1980s, when CAD first started displacing drafting tables. Download Now
Prototyping has always been a critical part of product development. Download Now
As the cloud is increasingly adopted for product development, questions remain as to just how cloud software tools compare to on-premise solutions. Download Now
|
RE: Relationship: Locked rotor amp and full load amp
The locked rotor current is the measured current with the rotor locked and with rated voltage and frequency applied to the motor.
The amount of current a motor can be expected to draw under full load (torque) conditions is called Full Load Amps.
I hope this helps.
Bob
RE: Relationship: Locked rotor amp and full load amp
LRC at rated voltage can be determined from KVA code and horsepower (both on the nameplate).
FLA is usually on the nameplate.
=====================================
Eng-tips forums: The best place on the web for engineering discussions.
RE: Relationship: Locked rotor amp and full load amp
Blacksmith
RE: Relationship: Locked rotor amp and full load amp
These code letters and multipliers are also listed in NEC Article 430. I would suspect there is such published relationship for IEC motors as well.
RE: Relationship: Locked rotor amp and full load amp
Hi place1234;
For standard motors similar to NEMA DESIGN B the ratio LRC/FLC is 5.0 to 5.6, this ratio range corresponds to the code letter "F".
For different type of design, the Nameplate has the "code letter designation".
RE: Relationship: Locked rotor amp and full load amp
Best regards,
Mark Empson
http://www.lmphotonics.com
RE: Relationship: Locked rotor amp and full load amp
RE: Relationship: Locked rotor amp and full load amp
RE: Relationship: Locked rotor amp and full load amp
RE: Relationship: Locked rotor amp and full load amp
I read your post and was thinking "Didn't I already post something?". I started to get worked up because I thought maybe someone red flagged my post. Then I realized it was a very similar posting in a completely different forum!
You are essentially right, with the caviat that itsmoked brought up, but I think the OP was trying to get a formula for determining the relationship between the two, and the other posts explain it well.
Bottom line, there is no grand unifying formula because it is different on different motor designs, but LRC is going to be "somewhere" between 500% and 850% of FLC in a Squirrel Cage Induction Motor. In Wound Rotor Induction Motors it is totally dependant on the rotor resistance during start. Synchronous Motors can be very different, again depending on design. I am working on one right now that is only 280% so we have to custom design an overload curve to rotect it.
"Our virtues and our failings are inseparable, like force and matter. When they separate, man is no more." Nikola Tesla
Member, P3
machmech (Industrial)
Hello Jraef
electricpete (Electrical)
Not measured in the field like that but sometimes measured in the factory like that.
itsmoked (Electrical)
electricpete; jraef must have 6 fonts!! and 2 colors! Dressed up like a par-tee gal.
electricpete (Electrical)
I guess fonts was referring to another post. I have noticed that from jraef. But he's got some competition over in the power engineering forum from cuky who produces some real flashy posts (and also full of good info like jr).

itsmoked (Electrical)
Hahah...hmmm.. not even an animated one.. tisk tisk.
davidbeach (Electrical)
So, itsmoked, where do you get all those smiley faces?
machmech (Industrial)
Hi Folks
itsmoked (Electrical)
davidbeach; somebody noticed!? 
davidbeach (Electrical)
itsmoked - thanks. I had long ago found the basic smileys, but hadn't ever noticed the links for more.


jraef (Electrical)
Oh oh, I smell a "Smiley Barrage" coming now!



Read the Eng-Tips Site Policies at FAQ731-376
RE: Relationship: Locked rotor amp and full load amp
The OP posted the word relationship and I misunderstood since I thought of metering under two entirely different conditions. Then Maypot posted "The locked rotor current is the measured current with the rotor locked and with rated voltage and frequency applied to the motor." I wondered if anyone in the field takes a reading like this, if so only reason I can think of is lack of in rush current capture on meter or extreme testing.
I have a handy Little Lewies manual and it gets me ballpark. And yes the other guy's responded well, But your use of a few more fonts makes things crystal clear.
Once again I Stand corrected.
Thank you Itsmoked and Jraef
RE: Relationship: Locked rotor amp and full load amp
What fonts?
=====================================
Eng-tips forums: The best place on the web for engineering discussions.
RE: Relationship: Locked rotor amp and full load amp
Now I think electricpete is using a PC XT with a mono screen and one font loaded.
RE: Relationship: Locked rotor amp and full load amp
My computer? Not quite an XT but close. My wife gets the superwhambeeydyne computer and I get the dog computer. I guess we know who wears the pants around here. Here comes my flashee smiley face. Get ready.
=====================================
Eng-tips forums: The best place on the web for engineering discussions.
RE: Relationship: Locked rotor amp and full load amp
RE: Relationship: Locked rotor amp and full load amp
RE: Relationship: Locked rotor amp and full load amp
LOL Seek and ye shall find, I had a feeling I'd be taken to the wood shed for that whoopin! Have a good weekend.
Thanks
RE: Relationship: Locked rotor amp and full load amp
Oddly it took a while for me to stumble across them.
Directly below the window you type in to post here, there is a box that sez "Emoticons/Smileys".
You should have a check in its box [default setting I think], this lets a reader see Smileys and Emoticons.
Click on the "Emoticons/Smileys" words.
A window will open that shows a zillion Smileys(non-animated). At the top of this column there are the titles "Animals" "Animated" etc., etc., click these and look around.
If you want to use one, just highlight the [xxxxx] in the left column including the [ and ] and drag it into your response, or copy&paste. That's all there is to it.
Now for colors. Very oddly the only instructions for this are in the "Preview Post" window.. {no sense at all} There you can read that for color, Example:
{color red}words to be colored{/color} would make the words in between the bracketed stuff the color specified. IF THE "{" brackets are actually "[" type brackets. I couldn't use them or they would've been processed causing words to be colored
Have fun!
RE: Relationship: Locked rotor amp and full load amp
RE: Relationship: Locked rotor amp and full load amp
Just FYI for those who need to know, if you look down below the "Your Reply" window at the bottom of the page, there is a little check box that says Process TGML. If you click on that phrase itself, you will get a popup window that explains how to do Bold, Underline, Italics, Super / Subscripting, and of course, the infamous colors.
"Our virtues and our failings are inseparable, like force and matter. When they separate, man is no more." Nikola Tesla
Member, P3
electricpete (Electrical)
Smiley fight 
)
itsmoked (Electrical)
Hahaha. Who sez EEs are sticks in the mud.
electricpete (Electrical)
My wife sez but wadoz sheno?
jraef (Electrical)
Where did you find those smilies E-pete? They are not on the list provided by the admins.
electricpete (Electrical)
Type in the following address 

itsmoked (Electrical)
Good..grief! The heck with Disneyland. I'm goin to planetsmilies!





jraef (Electrical)
Now I really wish I was still innocent of this knowledge. 
Read the Eng-Tips Site Policies at FAQ731-376
RE: Relationship: Locked rotor amp and full load amp
(internet version of food fight?
Ok, enough's enough.
=====================================
Eng-tips forums: The best place on the web for engineering discussions.
RE: Relationship: Locked rotor amp and full load amp
And thanks jraef.. would've taken me another year to notice the TGML stuff.
RE: Relationship: Locked rotor amp and full load amp
Did you guys notice when the first smiley whacks the second smiley with a fish that the second smiley ends up with blood on it. This is really bothering me. Smiley blood or fish blood?
=====================================
Eng-tips forums: The best place on the web for engineering discussions.
RE: Relationship: Locked rotor amp and full load amp
RE: Relationship: Locked rotor amp and full load amp
www.planetsmilies.com
They have got a pile of smilies
Pick a category on the left. That will take you directly to a page of smilies or else a page with links of smilies in groups of 72. When you find a smilie you want, cut/paste the address from the box below it.
Use the [img ] tag to display the link.
For example
[img http://www.planetsmilies.com/smilies/party/party0003.gif]
displays:
=====================================
Eng-tips forums: The best place on the web for engineering discussions.
RE: Relationship: Locked rotor amp and full load amp
RE: Relationship: Locked rotor amp and full load amp
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!