Hopefully you have transformers to boost the voltage however, otherwise you will either have to limit your max. speed or oversize your motors.
I have been runnig a Automation Direct GS1-22PO VFD for about 20 hours with a 230VAC 3ph 400Hz input. As one might suspect, Automation Direct will not OK this input frequency. An engineer I contacted at Yaskawa felt that either the MOV of the input diodes would be the first to fail in their J7 series drive (almost identical in capacity to the GS1), but wouldn't guess as to whether there would be a quick failure or it would happen over a long term. jraef's quote from another thread says 400Hz "may" be a problem. Since several of the GS1 units have run a few hours with 400Hz on the input, I can surmise that the failure won't happen quickly. I have not found anyway to test the unit other than running the normal operation sequence. I would be possible to set up a simple automated test rig that would allow cycling the drive for long periods of time.
I have not found a manufacture that offers a 400Hz input drive. I can not use the Automation Direct drive in production as it is made in China. I didn't find frequency ratings on either MOV's or the diodes used for the rectification. Is the 400Hz really a problem or is it just the fact that these companies haven't tested under those conditions. I don't imagine that there is much of a market for units that are rated at 400Hz.
I'm looking at a quantity of 200, so probably most manufactures wouldn't be interested in providing a custom drive anyway.
Any ideas on where I should go from here will be appreciated. The rest of the system is all working and the customer is ready to go, but without a drive the project is stalled (no pun intended).