I am looking for a solution. I have 7.5 HP pump motors controlled with VFD’S. I am asking can a Quattro 15kva supply power to 2 of them. So max load around 11kva. The VFD’S all have line reactors and noise filters. I’m concerned about harmonics causing the Quattro to not work.
The not to work part… It will possibly just have a lot of interesting noises and overload warnings.
Are you planning on using air conditioning? If not you may need to think bigger as the heat alone from working at this load will cause derating.
This is to drive 2 weg inverters that are 15hp inverters so they can safely derate to do the single phase to 3 phase to drive the 7.5hp water pump motors.
I’m looking for a power outage solution. Using a 15kva quattro to drive 2 WEG VFDS, each connected to a water pump motor. The quattro would be connected to a 48v battery bank.
A 15kVa will derate to 7.5kVa when the environment and then consequently the inverter is hot so will be way under the 11kVa power demand.
The system will shut down within the first half an hour on temperature alarm. If not before. Use air-conditioning if you need it to be stable and have longevity.
think about using 2x 10kVA in parallel.
Thanks for the reply s. 2 each 10kw in parallel sounds good, but my issue is i don’t want to spend the money to try, i need some assurance it will work. I have 4 each 7.5hp motors on VFD’S. I can do 2 each on each victron setup. I just need to know if the victron low frequency inverters CAN take noisy VFD’S and work reliably. Hoping to get some engineer or someone with high hp VFD driven motors on their inverters, with a sucess story. If there is a solution, are there parameters that need to be adjusted to make it work…things like that.
looking at the data sheet, the max continuous power of the 15kVA at 40C is 10kW.
VFD’s should produce a load with near unity power factor - if they are any good. The inverters can handle +/-0.8 pf.
A 7.5HP motor should produce a load of ~6kW - so the answer as to whether or not you can run 2 from one inverter depends on whether the motors are fully loaded. At 65C, the continuous power drops to 7kW, so it looks like you need 1 inverter for each VFD.
Seriously at this power level you ought to be looking at 3 phase machines: even if your VFD’s could accept a 3 phase input this could improve the situation. 3 phase machines are smaller and more efficient than single phase motors.
Up to 4 inverters (15000) can be paralleled, however, you might just be able to run all 4 motors from 3 inverters.
Thanks for the detailed reply. VFDS are WEG CW09, 15hp , they are high quality. They can take single or 3 phase. Had to get 15hp model to handle 7.5hp on single phase and add a external cap. My issue is 3 phase is not available from mains. The generator, only for power out conditions, can’t run the VFD’S without freaking out and cycling power. Despite isolation transformer, line filters, and line reactors. It’s not worth the trouble of trying to setup the VFD’S for switching from single phase normal to 3 phase backup.
So I’m exploring getting inverters and a bank of 48v batteries to handle the worst cast load, which is all 4, 7.5hp motors running pumps for 15 minutes for a fire flow requirement. The system normally runs on 1 motor at 1/2 load. I could have a small generator charge the batteries for the duration of the power outage. Probably the smallest generac propane powered home type. We have a 500 gallon tank.
I need to know for sure the inverter will work, even 1 inverter per motor VFD, without shutting down.
Another question, if i parallel connected 3 each, 15kwa inverters, can i use a single rack of 48v batteries connected to all 3 inverters?
This can be overcome: If the 3 phase inverter set is set up to charge independently, then you can have AC in on one phase, and still invert the other 2 phases, however additional Ac/Dc charging may be required.
If this is the case, then a single inverter can cover the charging requirement, and your battery can cover the ‘fire’ load. Lithium batteries will typically be 0.5C rated - i.e. 2 hours for charge/discharge, lead batteries can do better, but won’t last as long. Custom lithium batteries can also do 2C, i.e. full charge or discharge in 0.5 Hour. So battery type is an important design issue.
The only way to do this is to try it*. I see no issue with this. IF the VFD will accept 220V input, and NOT need a ground reference (110-0-110) , then an auto transformer is not needed. If you need the ground reference then an auto transformer needs to be able to handle the unbalanced current only.
- Buy 1 inverter, use 4 car batteries, and hook up one VFD / Motor as a test. Don’t bother wiring to mains AC at this stage. Just the batteries, inverter and VFD / Motor.
Thanks for the reply. Will be using lifepo4 server rack batteries. Can do a external charger, i have 4 100ah 12v lipos i could try with.
Trying is a great suggestion, just don’t want to buy and if it can’t, figure out how to sell.
I will contact a USA dealer and ask their return policy.
BTW, i looked into a Flexboss eg4, the company said it won’t drive a big VFD.
I would not expect to much problem with driving a VFD - these are easier to start than DOL motors. That’s why I suggest trying this with one unit. If it turns out not to work on the VFD, then you can use it to back up the rest of the Office / home etc. The Victron gear does have great surge capacity intended for motor starting. I have a battery spot welder- transformer type, that takes 8.25kW 10ms pulse of energy to do a weld. I’m running this happily from a pair of 3000W multiplus 2’s in parallel, before when I only had one inverter, the weld’s were poor, and I had to run a 2000W motor with a capacitor across the line to provide the surge power. The welder does not cause any regulation problems for me - I also run a couple of PC’s off the same inverters.