Previous in Forum: Formula for Cable Sizing   Next in Forum: Battery Charging
Close
Close
Close
9 comments
Rate Comments: Nested
Anonymous Poster

Squirrel Cage Electric Motor

10/13/2009 8:48 AM

I RECEIVED SQIRREL CAGE MOTOR ....18.5KW, 50HZ, 34.5A, COSTHETA .91, r/min - 2940 , IA/IN 6.8

But our Order specification says that

18.5kw,380V/3PH/50HZ,3000RPM,NO OF POLES =2, FULL LOAD CURRENT=36, NO LOAD CURRENT 20A , LOCKED ROTOR CURRENT 620 ,LOCKED ROTOR TORQUE 153

EFFICIENCY 100% FL = 87.5

MOTOR IS DOL TYPE

IS IT OK WITH THE SPECIFICATION AND RECEIVED MATERIAL?

Reply
Interested in this topic? By joining CR4 you can "subscribe" to
this discussion and receive notification when new comments are added.
Power-User

Join Date: May 2009
Location: Some where on Earth !!!.
Posts: 243
Good Answers: 2
#1

Re: Pls help with squirrel cage electric motor

10/13/2009 12:51 PM

What's the voltage level specified in the delivered motor?Rest seems to be ok....& I dont know the ratio IA/IN in your requirement.starting by nominal full load current?

__________________
"Know something about everything and everything about something"
Reply
Power-User

Join Date: Jun 2009
Posts: 262
Good Answers: 1
#2

Re: Pls help with squirrel cage electric motor

10/13/2009 12:59 PM

You received almost what you ordered (if the new motor is also 380V). Only LRC 620A for a motor having FLA 36A seems to be too much !

Reply
Guru

Join Date: Feb 2009
Location: Houston, USA
Posts: 946
Good Answers: 244
#3
In reply to #2

Re: Pls help with squirrel cage electric motor

10/13/2009 10:07 PM

Most probably, locked rotor current 620 means 620% of full load current. The vendor proposal is 680%. It is slightly higher but can be acceptable (depends on the tolerance level). Try to get the full load efficiency, no load current, locked rotor torque from the vendor and verify it with your requirement.

And obviously, the vendor didn't mention the voltage. It is very important that it meets the order specification.

- MS

__________________
"All my technical advices in this forum must be consulted with and approved by a local registered professional engineer before implementation" - Mohammed Samad (Linkedin Profile: http://www.linkedin.com/in/msamad)
Reply
Anonymous Poster
#4

Re: Squirrel Cage Electric Motor

10/13/2009 11:22 PM

Sirs

i gave details of our specification and recieved specification

but our specification says that 3000rpm ..recieved motor says that 2940 r/min(rpm) ...is it acceptable. I calculated by rpm=120xf/p but (f=50hz,p=2) but 2940 is not comming 3000 is comming.

my motors make is bartec and model is 4KTC 180 M-2

In recieved motor given that A=34.5 but our specification says that full load current 36 and no load current is 20 but recieived motor doesnt mention about no load current

locked rotor current (%FLC) in our specification is 620 but recieved motors name plate says A= 34.5( I think this is full load current) and IA/IN=6.8 ( could not able to understand whether it is locked motor current /full load current ratio or not

SIR'S PLZ HELP ME...IS THIS MOTOR ACCEPTABLE

I WILL BE GREATFULL TO YOU

DAVID

Reply
Power-User

Join Date: Aug 2008
Location: East
Posts: 117
Good Answers: 6
#6
In reply to #4

Re: Squirrel Cage Electric Motor

10/14/2009 12:58 AM

David,

Your motor specification stating 300rpm is the synchronous speed of the motor which as you rightly said is the value you get from the formulae 120f/p. The manufacturer is giving you a 2 pole motor and thus having a synchronous speed of 3000rpm. The value of 2940 rpm stated in the manufacturer data sheet is the running speed of the motor when driving the load, i.e it takes into account the slip.

The full load current is ok. The locked rotor current is 6.8 times that of full load current whereas your spec called for 6.2 times. However for this size of motor this should be acceptable. Note that IEC and other international standards allow for a positive tolerance above the 6.2 times given by you.

The offered mtor is hence OK.

__________________
Atlas Shrugged - JGD
Reply
Anonymous Poster
#7
In reply to #6

Re: Squirrel Cage Electric Motor

10/14/2009 4:01 AM

Dear sir

I am very greatfull to you for your quick reply and mentioning you thanks from my heart. MAY I HAVE YOUR NAME SIR

god bless you

thanks

david

Reply
Anonymous Poster
#5

Re: Squirrel Cage Electric Motor

10/13/2009 11:39 PM

SIR

I FORGET TO WRITE THE VOLTAGE SPECIFICATION

voltage in our specification is 380/3PH/50HZ

RECIEVED MOTOR SAYS

V HZ KW A COSPTHETA r/min IA/IN

D400 50 18.5 34.5 0.91 2940 6.8

Y690 50 18.5 19.9 0.91 2940 6.8

OUR SPECIFIFICATION MENTIONED THAT STARTING METHOD IS = DOL (DIRECT ON LINE)

BUT FREQUENCY SAYS 3000RPM but recieved motor says 2940 r/min is it ok?

thanks

david

Reply
Power-User

Join Date: Jun 2009
Posts: 262
Good Answers: 1
#8

Re: Squirrel Cage Electric Motor

10/15/2009 12:23 PM

Maybe the Guest (David?) needs a synchronous motor?

Reply
Active Contributor

Join Date: Oct 2009
Location: Delhi
Posts: 11
Good Answers: 1
#9

Re: Squirrel Cage Electric Motor

10/21/2009 1:07 AM

David don't forget the slip in induction motor.

Everything in the specification looks good, but it depends on application and type of loads.

Suvek Kumar

__________________
Er. Suvek Kumar
Reply
Reply to Forum Thread 9 comments
Copy to Clipboard

Users who posted comments:

Anonymous Poster (3); Current Maarey (1); giri (1); msamad (1); suvekkmr (1); Yuri B. (2)

Previous in Forum: Formula for Cable Sizing   Next in Forum: Battery Charging

Advertisement