About the input to VFD

kcbibek310kcbibek310 Posts: 21Registered Users ✭✭
Here i got some confusion. I have a pump of capacity 2.2 kW and VFD of 3 kW. Now i am willing to know, whether i have to consider the VFD's input power or motor input power while calculating the size of solar panel. 


  • BB.BB. Posts: 28,040Super Moderators, Administrators admin
    Generally, the size/power requirements of the motor is what you will design the minimum array for.

    However, you can have a larger array and it will work fine--And generally will start the pump earlier in the day, and run later into the evening--Pumping more water.

    Just make sure the array voltage does not exceed the max input rated voltage. And, possibly you will need a circuit breaker on the input to the VFD to protect wiring/VFD input wiring against short circuits (breakers/fuses are there to protect the wiring against too much current--Protective devices are not there to protect the electronics/load--Or make the loads "last longer").

    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • kcbibek310kcbibek310 Posts: 21Registered Users ✭✭
    Can i use solar panel of capacity 2.2 kW for above mentioned system?
  • mcgivormcgivor Posts: 2,302Solar Expert ✭✭✭✭✭
    There are many considerations which will factor into the equation, but having an array with a greater capacity than the pump rating would be preferred over a marginal capacity, which may, under less than ideal conditions, fail to support the pump. As pointed out the added advantage would be longer run times, other than just the peak hours, bare in mind panels put out less than their rated output, especially in hot environments. Attached link has a calculator along with information which may help you understand what it is you are dealing with, to simply say, yes that will, or will not work, would in my opinion be irresponsible, as information is very slim at this point.
    1500W, 6× Schutten 250W Poly panels , Schneider MPPT 60 150 CC, Schneider SW 2524 inverter, 400Ah LFP 24V nominal battery bank 

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