Answer / prakash veer singh

Our calculated load is 110KW . Normaly, we give 80% load on
DG for best and long opration . DG pf is 0.8.
So DG rating = 110/0.8
= 137.5 KVA
we use 150 KVA or high then.

Answer / pillay

D.G if ac is rated in KVA.Usually the alternator is rated at 0.8 pf. So KW/PF=KVA. 110/0.8=137.9.KVA.
Now the D.G must have some spare power to take care of starting current and a bit of future expansion so we load the D.G at 75%.
137.9/.75=183.8KVA
Now you can buy the nearest available D.G in the market.
Maybe 175KVA or 185 KVA

Answer / mahesh sali

FOR 110 KW , SAY AT 0.8 PF.

WE KNOW THAT
KVA = KW/PF
KVA=110/0.8
KVA = 137.5 KVA
ASSUME THAT ABOVE LOAD IS MOTOR
FOR
AS PER NEC SAY THAT
25% EXTRA AS PER NORMS,
I=KVA/1.732*V ASSUME:- V-415 V
I=191.29 AMPS.

THEREFORE,
I = 1.25 * 191.29
I= 240 AMPS.
KVA= 1.732 *240*415
KVA=173 KVA , DEMAND LOAD
AS PER RULE
80% LOADING ON DG SET
KVA=173/0.8
KVA=216 KVA DG SET RATING
AS PER STD.RANGE OF DG SET -725 KVA AT 0.8 PF , 415 V
216

Answer / sanjay vishwakarma

CONSIDERING 110kW AS INDUCTIVE OR MOTOR LOAD
Ir (RUNNING CURRENT) WILL BE 110*1000/1.732*415*0.8
Ir = 191.3 AMPS

CONSIDERING MOTOR STARTER AS STAR-DELTA,
Is (STARTING CURRENT) = 3 TIMES OF Ir (RUNNING CURRENT)
Is = 3 * 191.3 = 574 AMPS

IF MOTOR WILL START ON NO-LOAD CONDITION, THEN STARTING
CURRENT WILL ALWAYS BE LESS THAN 574 AMPS

DG SET RATING SUITABLE TO START 110kW MOTOR LOAD IS 365KVA

365KVA DG SET AT 0.8 PF WILL DELIVER 507 AMPS. SINCE DG SET
ENGINES ARE PRIME RATED I.E. AFTER EVERY 12 HRS, DG SET CAN
BE RUN ON 110% LOADING FOR 1 HOUR.

SO, 110% OF 507 = 557.7 AMPS,

HENCE, 365KVA DG SET IS SUITABLE TO START A MOTOR
(INDUCTIVE) LOAD OF 110kW


WILL BE IF MOTOR WILL BE STARTED ON NO-LOADSINCE MOTOR
SHALL START ON NO-LOAD

Answer / sahab ram verma

Dear sir Please Help as per Bellow Mention Load For Mahindra DG Set

Ac 1.5 Ton=8
Ac 3 Ton=1
Geyser 4 KW=6

Answer / bal

Calculated load is 110kw.
considering 10% spare for future load growth
= 110 x 1.10
= 121kw

Operating at 0.8 pf,
= 121/0.8
= 151.25kVA

You can select the next available rating in market.

Answer / v.c.k

For the Calculated load of 110KW

for DG Selection,we mush know phase

therefore we consider 3 phase

A=kw*1000/1.732*45
=110*1000/1.732*415
=110000/718
=153A

therefore we select the next higher stage DG, its means
225KVA (If available we choose 175KVA or 200KVA)

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