Answer / keshav sain

Always Apply the formula IR =System Voltage+1 Mega Ohm

Sys.Voltage is 11 kv,
So 11+1=12
Value should be 12 MOhm

Answer / raghavendran.r

The thumb rule for IR value is that per kV of system it
must have atleast 1MOhm of insulation Resistance.

But We have a formula Which says

IR = Sys.kV + 1MOhm.

if System voltage is .415kV then Minimum Insulation
required is .415 + 1MOhm = 1.415MOhm.

Answer / md. m. u. noman

IN my traning preod i face this question.i have learn 2 mathod.
1st IR >= system voltage in M ohm +1 M ohm.
for example, 3.3kV motor IR= 3.3+1 =4.3M ohm....that means
greater or equel to 4.3M ohm..

2nd is IR >= (20*V)/(1000+2P)M ohm.(at 25 degree celcise)
where , V= rated voltage ofmotor;
p= power in kW......

Answer / kamal

v =IR k=1000 p=11000 v=415

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