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Join Date: Sep 2009
Posts: 16

re-rate of induction motor

10/07/2009 6:12 AM

I want to re-rate an induction motor which is rated 3ph,50 hz, 2965 r.p.m , 159 KW ,3.3 KV , 35 A. how to do?

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Guru
United Kingdom - Member - Indeterminate Engineering Fields - Control Engineering - New Member

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#1

Re: re-rate of induction motor

10/07/2009 8:38 AM

Obtain and follow the manufacturer's instructions.

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Guru

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#2

Re: re-rate of induction motor

10/07/2009 10:48 AM

What do you mean by re-rate?

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#3
In reply to #2

Re: re rating of induction motor

10/07/2009 10:54 AM

it is actually rerating

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Guru

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#4
In reply to #3

Re: re rating of induction motor

10/07/2009 11:17 AM

What is re-rating? Is it uprating or derating?

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#5
In reply to #4

Re: re rating of induction motor

10/07/2009 11:31 AM

it is uprating? what is maximum uprating is possible of these machine. the machine details ----

3 phase

50Hz

2965rpm

Insulation class F

Connection Star

3.3kv

35A

159kW

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Guru

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#6
In reply to #5

Re: re rating of induction motor

10/07/2009 11:59 AM

What is the Service Factor of the Motor? And, what is the operating ambient temperature?

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Commentator

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Location: Centurion, South Africa
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#7
In reply to #5

Re: re rating of induction motor

10/09/2009 1:20 AM

The factors that influence the output of a motor are as follows:

Ambient temperature (the motor was designed and manufactured for 40°C, and your average ambient temperature on site is maybe only 20°C, you may increase the output)

Above mean sea level (the motor was designed for 1000m amsl but your site is at sea level, you may increase the output)

You can get a table with these 2 factors combined which will show how to rate the motor (increase or decrease the motor output), from any reputible motor manufacturer.

Temperature rise of the motor (if your motor was designed and manufactured with a class B temperature rise and the motor insulation is class H, you will have spare thermal capacity available in the motor insulation system to increase the output of the motor) You need to have the original data sheet of the motor to determine this one-contact the motor manufacturer.

Remember by increasing the output of the motor you will decrease the motor life. The best will be to speak to the original manufacturer of the motor.

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