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bmadhu_srao
Commentator

Join Date: Nov 2007
Posts: 86

Insulation Resistance

10/29/2009 11:14 AM

hello everyone,

I am planning to implement a motor preventive checklist inour block,

I have considered below points.

1. Temperature of the motor after, 30min of operation

2. Insulation resistance, Winding resistance

3. Abnormal noise

4.Vibrations in the motor if any

5. body earthing and current drawn

I am i missing any thing else important, and what has the limit for values for industrial motors(most being being FLP)i.e what has to be practical insulation resistance, sizing of earth conductor, acceptable percentage of current drawn on no-load

Bye and thanks
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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
#1

Re: Insulation resistance

10/29/2009 11:38 AM

How big are the motors, and what are they doing?

What country are they in?

What does the country's electrical code say on the topic?

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nesubra
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Join Date: Nov 2006
Posts: 729
Good Answers: 2
#2

Re: Insulation Resistance

10/30/2009 8:42 AM

Don't make us a party to deprive some consultant who will do this

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electricalexpert65
Guru

Join Date: Oct 2009
Posts: 2061
Good Answers: 169
#3

Re: Insulation Resistance

11/01/2009 5:39 AM

Refer to IS 732, if you are from India. This gives the minimum permissible insulation resistance for motors.
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bmadhu_srao
Commentator

Join Date: Nov 2007
Posts: 86
#4

Re: Insulation Resistance

11/11/2009 1:33 AM

Hello gurus,

Ours is a chemical process plant in india, we have motors rangin from 0.5hp to 175 hp, all being induction motors,1 pahse and 3 phase. with all types of startes(DOL, Soft staters, VFD and Star-Delta).
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electricalexpert65
Guru

Join Date: Oct 2009
Posts: 2061
Good Answers: 169
#5
In reply to #4

Re: Insulation Resistance

11/14/2009 2:11 AM

As per IS 732-1989, vide Cl. E.2.1.4, the minimum insulation resistance of motors should be:

R = {(20 En) / (1000 + 2P)}

where,

R = Minimum Insultaion Resistance, in Mega Ohms

En = Rated Phase to Phase Voltage

P = Rated Power in kW

Hope the above is clear.
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Users who posted comments:

bmadhu_srao (1); electricalexpert65 (2); nesubra (1); PWSlack (1)

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