Hi there,
Thanks a lot for sharing knowledge in past, i just not learned the technical bit but also some sarcastic and witty comments. simply amusing not harsh.
Here is the another silly one, i have done math and physics and the theoretically calculations make sense but i am wondering how practical would it be?
" I have a 45kW submersible bore hole pump and trying to reduce/correct the size of the diesel generator.
Motor Technical data:
Manufacturer: Franklin Motors
Rated 45kW/60HP , 6" with 210kg total weight (motor+pump)
Thrust = 2800kg
Full load current = 93.2 Amps operating @ 50Hz
Nominal RPM = 2875
Locked Rotor Amps (Inrush) = 526 Amps.
As per my calculations i can use a 80kVA Genset to run this 45kW motor with Soft-Starter or VFD, however, people with 20/30 years field experience are saying they have never seen a 80kVA Genset running 45kW bore hole pump motor. 
Here are my calculations (very simple math )
After considering de-rating factor (temp and all) 80kVA genset = 63kW @ 0.8pf
FLC = 109 Amps
DG Motor Starting Capability@ 30% voltage Dip = 196kVA = 272 Amps
PMG + AVR fitted with 300% short circuit capability.
With a 272 Amps starting capability and Soft-Starter/VFD, Genset should be able to handle 526 Amps Inrush current followed by FLC of motor i.e. 93 amps. If i consider losses up to 10% (11amps , 109-11 =98 amps) Genset should be able to provide enough amps for motor running @ 100 % load.
Due to lack of practical experience, limited resource (a simulator to run and test my cals/findings) i am not able to proceed forward without having some inputs from experienced and knowledgeable people.
Currently, client is using 150kW Genset to run 45kW motor with Soft -Starter. In my feasibility report i found out that 150kW genset is subject to Glazing due to load being less than 40% of Genset total rated capacity.
Please shed some light. If you need more clarification/technical information, feel free to ask. I appreciate your time and knowledge.
Regards,
Straya
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