Answer / sudhanva madhukar mahamuni

Hello To every One,

This is Sudhanva Madhukar Mahamuni Electrical Design
Engineer. The reason behind the same is not a alternator /
generator. The reason behind the same is diesel engine.
(Surprise!!!!!!!!!!)

Carefully read the catalog of DG Set for e.g. for 750kVA its
written as 750kVA / 600kW @ 0.8 pf. It means that alternator
size is 750kVA and 600kW is of Diesel engine. It means that
diesel engine can delivery only 600kW power. so if we like
to maintain the same then we need to keep 750kVA load on DG
@ 0.8 (750 x 0.8 = 600kW.

But assume that your load on alternator is 600kVA then you
are allow to improve your power factor till unity i.e. 1.
Therefore load on engine will be 600kVA x 1 = 600kW.

Summary : if multiplication of electrical load (in kVA) to
Power Factor will be upto or less than kW rating of diesel
engine then we can play with power factor i.e. lead or lag.

Note : If we will not do as above mentioned and improve the
power factor then engine will cease off (dead) i.e. cant
repair or modify.

For further clarification you can call me or mail me on
sudhanvamahamuni@structwel.com or sudhanvamahamuni@gmail.com

Regards

Mahamuni
9769317386

Answer / prakash veer singh

In DG ,we maintein pf .8 because , if pf decrease than
alternator has overload due to more current dron by load .
And if pf is increase ,than engine has overload due to
increase potational (volt ).

So maintain DG pf is 0.8 .

Answer / vinodth

consider 1 transformer having the power 125mw,33kv...
1)p=125mw,
v=33kv,
cosQ=0.8
p=1.732VlIlcosQ
I=125000/1.732*33000*0.8
I=2733.7
2)cosQ=0.7
I=125000/1.732*33000*0.7
I=3124.29
loss=i*ir..if the pf reduces,then loss get increases...v
cant maintain the pf as unity,tats y the pf s maintained as 0.8

Answer / jayashree

Mr. Vinodth, the query is about DG. Please answer it again.

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