MAIN QUESTION:
Which inverter for 3-phase motor with 11kW (starting corn mill)?
Can i use star-delta-switching with 3x MPII 8k(or 10k) or
do i need a frequency transformer to start the motor?
(Possible voltage peaks when switching star to delta)
LOCATION: Austria, Europe.
Power connection to the grid: 3 phase + Neutral from nearest trafo, 63A fused
MY PV SYSTEM: Grid parallel, see picture
CONTEXT: I want to route the main power from my pig farm over 3 x MultiPlus 8k (or 10k if necessary),
to make all systems running in case of power failure (power pole cables here relatively break often).
I will build a 34kWp (42+42 modules East/West on a high building) and
40 / 50 kWh Battery (8 / 10x Pylontech 5000) PV system this year, so why not
go the full distance. Also this is the last year for big grants from the state and my district.
CORE PROBLEM: Starting the 11kW corn mill IN THE WORST CONDITIONS, no help from grid or the symo.
(Corn mill: just imagine a 11kW motor with a 60kg, 70cm diameter round
steel frame with hammer blades directly attached to the motor).
At the moment the 11kW motor is started via star-delta-switching (first 10s Star 3x230V, then delta 3x400V)
This reduces the required starting power to 1/3 in theory, but you can get possible voltage peaks
when switching star to delta, due to phase shifts
I have another 4kw Motor + 2-3kW background running while the mill is working (2x 45min per day),
but the rest starts delayed from the mill. In a blackout scenario you could cut other stuff down to only 2kW background ==> 13kW continuous power.
ALTERNATIVE: If that idea proves to be too expensive/inpractical, i will just use 3x Multiplus 5k,
if the sun is a little assisting, i can cover almost those max continuous power times.
In the worst case the pigs dont get feed for like 1 day, but water/heating/airconditioning/lightening would still work.
Information on that topic is kinda rare, so any help or input is much appreciated.
Thank you for your time.
