Quote Originally Posted by Voicecoil View Post
on which subject does the Bridgeport have pulleys connecting the motor to the spindle? Obviously at lower voltages you will get lower motor RPM.
It has a belt drive which i believe is a 1.5-1 ratio. I very much doubt I would be trying to drive this at anywhere close to it's max output and I can easily overcome most of the downsides of this just by reducing my DOC and better calculating the speeds and feeds. Hell, if i can get 30% of the normal max power it would turn this from a beautiful giant doorstop into a machine again!!

Quote Originally Posted by Voicecoil View Post
Going back to my original suggestion, rectifying & smoothing the mains to give ~325V @ abou 5KW will need some biggish capacitors which will draw hellish charging current spikes from the mains - using smaller caps that don't charge all the way when under load might make Powergen rather happier, but will of course reduce your available power.
To be honest I am going to have to figure this out as i go along, it is deeply outside of my comfort zone. I work with big AC all the time but DC, of this kind, is a mystery to me (but getting clearer as i look into it more). Getting this running is first on the list so I will give this a go and put fuses into the line so i don't do any damage. I have a few different caps i can use and i can trial a few different configurations to see how it is effected. Then I will further look at the control side, when i can get this to work.

Quote Originally Posted by Doddy View Post
I genuinely don't know the answer to this: Would it not be worth trialling without caps at first - the inductance of the motor windings will provide a hefty current stabilisation without throwing energy into expensive high voltage, high capacitance, high ripple caps?
I will try this too and let you know how it goes, so long as i don't do any permanent damage I am up for trying anything!

First things first though, i will have a bit of time tomorrow to do some measuring and calculations then will see where I am!

Thank you for all your help.