power supply questions

[SJ781]

I am going to run 3 320 servo drives with servos that have a max current of 30a so I want to be able to use the full 20a that the 320's provide I also want to run the most voltage I can the servos were rated for 90vdc. the 320's are rated for 80vdc. Will it be safe to run a ps that produces 79-81 vdc no load current. I know the voltage will drop when there is a load but will the voltage be to high when the servos are'nt running? My next question is should I run a sepperate ps for each drive or one ps. If I run one ps would I be ok with one that produces 30-40a. I doubt that the servos will ever all be at max rated current (20a) at once. Most likely only one will ever be at max at one time.

[balsaman]

You should run no more than 80 volts. 75 would be better. I would go with one powersupply, maybe around 30 amps.

Those are big motors. What are you driving?

Eric

[SJ781]

I'm driving a mill/drill the plans are to get 250ipm rapids out of it. I've got 4 - 79Vdc 7A power supplies but I don't think they will be enough to drive them. The servos are 2100rpms@72vdc and 690oz/in at 15A.