The converter output voltages are all about equal (230-235 volts) but the pump draws 13 amps on L1 & L2 and 7 amps on L3, which is the "manufactured" phase.
Definitely looks like a Capacitive Reactance Tweek is needed here!
I bet the 22µF Capacitor brings the load levels on L1 and L2 down to the 10 - 11 Amps range, and the "Pseudo-Phase" L3 may drift around the 8 - 9 Amp level, which would mean it might actually start doing some work!!!
As it is now, only L1 and L2 are doing any work - L3 is kind of slacking off (insufficient KVA available).
With additional XC (Capacitive Reactance), the "Pseudo Phase" L3 can contribute more work, therefore bringing the polyphase loads more into a balance.
Just do not expect a completely balanced load value here!
The polyphase motor is being driven more from 1 phase apparent power, than polyphase apparent power.
The "Pseudo Phase" L3 does not follow the same power curves & all that silly E-lecktricul Injunearring type stuff, as the lines derived from the Transformer - and the real disappointing thing: they are still only a Single Phase!
This setup really should have been specified to use a 1 Phase 3 or 5 HP Motor - a Capacitor Start-Run type would have been a good choice too!
I realize the design and ordering of the pump equipment was in the hands of others, so maybe some "constructive critsism" should be delivered to the specifying party(s).
"I feel sorry for that poor Motor, being subjected to that crappy power quality from the Phase Converter"