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7 comments
Participant

Join Date: Feb 2009
Posts: 3

ABB 3-Phase Motor, 12.5 KW - No Load Current

05/22/2009 11:28 PM

Friends ,

I have ABB Squirrel Cage Induction Motor 3 Phase, 12.5 K.W , used in Plastics Injection molding machine ,No load condition ( ideal ) it draws 11 AMPs current which I feel is too high . Kindly suggest what can be wrong with motor ?.

regards

Sarju .

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Guru

Join Date: Mar 2007
Posts: 2550
Good Answers: 105
#1

Re: ABB 3 Phase motor , 12.5 KW .No load current .

05/23/2009 2:54 AM

You never mentioned the Voltage or the rated current of the motor.

Typically the No load current is of the order of 25% of the FLC but, it may be a bit more too.

These current are usually the result of the extreme poor pf at those loads.

Compare this value with the FLC and if you get one > 40 or 50%, then worry.

Again if your FLC is OK, and you are going to run the machine in loaded condition, then why worry?

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Active Contributor

Join Date: May 2008
Posts: 17
Good Answers: 2
#2

Re: ABB 3-Phase Motor, 12.5 KW - No Load Current

05/24/2009 1:54 AM

Dear Sarju,

Normal No load current is around 30% of FLC, in your case it is approximately 50 %, Please check the input voltage as rated, if no it may be the reason, in some cases no load current more in few motors, ask manufacturer to give its test certificate, put motor in to service on load and check load current, is within limit, go ahead,

considering if motor running idle more, then change the circuit in the sence to switch off during idle time for conservation point of view.

Bye

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Guru
Canada - Member - Specialized in power electronics

Join Date: Feb 2008
Location: Montreal, Canada.
Posts: 1250
Good Answers: 77
#3

Re: ABB 3-Phase Motor, 12.5 KW - No Load Current

05/24/2009 9:54 AM

Are you sure you are in "No load"? The motor might be operating some pump that adds some friction or load. To make sure, disconnect the motor shaft from anything else.

Also, make sure that it rotates freely by hand. You might have years of accumulated dirt or a seased bearing in there.

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Power-User

Join Date: Apr 2007
Posts: 424
Good Answers: 10
#4

Re: ABB 3-Phase Motor, 12.5 KW - No Load Current

05/24/2009 8:43 PM

When we are talking about "NO" load, you got to understand the electrical terms of "NO LOAD" and what does it means.

"NO LOAD" means that an electrical motor is free from any connection or touching any mechanical parts and run freely without any load.

In your case, I do belived that your motor is still attach to your plastic injection machine. It either connected to your rotation screws or some parts of your plastic injection machine. Thus we don't consider that as NO load.

That why, your motor still consume 11Amps when your plastic machine is stand still.

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Participant

Join Date: Feb 2009
Posts: 3
#5

Re: ABB 3-Phase Motor, 12.5 KW - No Load Current

05/24/2009 11:14 PM

Sir ,

Thank you for u r guidance ,No load means I had complete de coupled the motor , it was run without any pump or load connected to it still current is 11 Amps which is high. Motor bearing is ok , all 3 phases draw equal current of 11 amps . Some say it will be design to run at higher current on no load is it possible ?.

regards

Sarju

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Anonymous Poster
#6
In reply to #5

Re: ABB 3-Phase Motor, 12.5 KW - No Load Current

05/25/2009 3:23 AM

some low speed motors say 740 rpm or 595 rpm motors draw more current on no load.That is quite normal as far as your motor does not draw more than the rated current on full load

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Power-User

Join Date: Apr 2007
Posts: 424
Good Answers: 10
#7
In reply to #5

Re: ABB 3-Phase Motor, 12.5 KW - No Load Current

05/25/2009 4:15 AM

Can you please give us the full data's of your motor specification as in the motor name plate and from the motor name plates we may able to understand the actual problem of your motor free load current problem.

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