Two 3 phase inverters in parallel

[Shaun Sparky]

I went to look at a new job site on a dairy farm and due to all the load shedding here in South Africa the farmer wants to install a solar inverter system for his dairy , the cows get milked between 3 and 5 in the morning and 3 and 5 in the afternoon. The system they have there is a 3 phase system with a few three phase motors and a bit of control gear , while the system is running it draws about 19,5 Amps per phase , what i will probably be needing are two 12 Kw 3 phase inverters hooked up in parallel to make up for the high start up current of the motors . Is there a formulae i could use to work out my current draw on those 3 phase inverters and the amount of 5,1 Kw 48 Volt lithium Ion Phosphate batteries i will be needing for each inverter and then of course i will have to work out out the amount of solar panels i will be needing for this job , one thing is certain , this job is going to cost this guy an absolute fortune.

 

[time2roll]

12kW at 48v is about 250 amps. Need to verify the input circuit recommended in the manual.
19,5 amps per phase at what voltage? 230?

 

[BentleyJ]

You definitely want to consider installing a Hyper Engineering Soft Starter on those motors, will make your life and the inverters life easier by reducing inrush by up to 70%. These are the 3 phase models available.

• SS5A04-27SN (460V, 60Hz, 04-27 FLA)
• SS4A04-34SN (415V, 50Hz, 04-34 FLA)
• SS3A04-27SN (380V, 50/60Hz, 04-27 FLA)
• SS2A04-28SN (208-230V, 50/60Hz, 04-28 FLA)

 

[Shaun Sparky]

12kW at 48v is about 250 amps. Need to verify the input circuit recommended in the manual.
19,5 amps per phase at what voltage? 230?

Yes 230 per phase with a neutral.

 

[Shaun Sparky]

You definitely want to consider installing a Hyper Engineering Soft Starter on those motors, will make your life and the inverters life easier by reducing inrush by up to 70%. These are the 3 phase models available.

• SS5A04-27SN (460V, 60Hz, 04-27 FLA)
• SS4A04-34SN (415V, 50Hz, 04-34 FLA)
• SS3A04-27SN (380V, 50/60Hz, 04-27 FLA)
• SS2A04-28SN (208-230V, 50/60Hz, 04-28 FLA)

Thanks