Cincinnati Milacron Arrow 750 Retrofit

I have a 390VDC power supply that I plan to use to feed power to the 8i20 card. The 8i20 card will be connected to a 275VAC 3 phase BLDC motor. How is motor braking affected by the big difference between the 390VDC power supply voltage and the 275VAC motor rating? If I set the Brake Threshold Voltage to 395VDC or 400VDC, will the motor only generate up to 275VAC of 3 phase AC power? If so, the braking threshold voltage will never be achieved and the brake will never turn on. Or, will the voltage continue to build up and trigger the 395VDC Brake Threshold Voltage? (I'm not entirely sure I understand how a coasting BLDC motor behaves)

Would I be better off with a lower voltage DC power supply closer to the rated motor voltage from a braking standpoint or it doesn't really matter?

275V AC RMS is 390V peak, so it might all be much the same.

You are rather close to the max rating of the 8i20, so I think that you definitely want to be fitting braking resistors.

Oh, ya. (I should've caught that) Thanks for pointing it out.