New build need some electronics guidance

[okami125]

Hi, I just received my allin1dc about a week ago. I’m in the stages of building my cabinet now. My machine is a ycm 40 with a milltronics centurion controller that was busted by the freighter in transit. so my goal with the machine is to use a single phase 240vac input feed my vfd for spindle power then rectify the current into 110vac for the rest of the machine. The main reason for this is I'm pretty limited on amperage and I know that stepping down from 220vac to 110vac will give me roughly double the amperage. so there is my question what amperage is everyone providing the allin1dc for the servos? My original thought was that 8.6 amps per servo would be roughly 26ish amps. but upon my math, I would need to provide 2 amps to the board itself plus a bit more I'm sure for things like my mister, lube pump, and limit switches. so I figured 35ish amps at 110v for the whole system. That's almost 4kva on a transformer versus the stock one milltronics used that's 1.5kva.
So I guess I'll just line out my questions down here to make them more clear.
1. What is everyone providing the allin1dc amperage-wise for the servos?
2. has anyone done a similar thing to what I'm doing with the 220vac to 110vac? if so what size transformer are you using?
3. My servos are 140vdc so I need to step down the voltage again for these I believe? What step down transformer size would I be looking for?

Included a picture of the mill post-transit, thankfully I had insurance

[tblough]

IIRC, Centroid's 110VAC transformer is 1.86KVA and their 220VAC transformer is 2.3KVA. I've been running my AllIn1DC conversion with a 2.5KVA transformer that I got a good deal on off eBay.

I have a 3Hp spindle motor, Centroid's later model 29 in-lb DC servos with 180VDC ratings, and I'm running the whole thing on a 20Amp service breaker.

[okami125]

IIRC, Centroid's 110VAC transformer is 1.86KVA and their 220VAC transformer is 2.3KVA. I've been running my AllIn1DC conversion with a 2.5KVA transformer that I got a good deal on off eBay.

I have a 3Hp spindle motor, Centroid's later model 29 in-lb DC servos with 180VDC ratings, and I'm running the whole thing on a 20Amp service breaker.

Hey thanks for the info, looks like if I want the easiest possible circuit then I should just pick-up centroids transformer?

[tblough]

It depends on what you need a transformer for. Centroid's transformers have 83VAC secondaries. When rectified that gives 120VDC which is suitable for their older DC servo motors. There newer motors are rated for 180VDC so you can rectify 120VAC directly without a transformer.

Even though I'm supplying my machine with 4-wire split phase 240VAC which I need for my VFD, I didn't want to run all of my servo motor power from one leg as that would really unbalance the two 120V legs. So I added a 240 to 120V single phase transformer, and rectified that to give me 170VDC for my servo motors.

I did use the neutral and the two hots for my other 120VAC loads like fans and solenoids, but I made sure to balance those loads on both legs.

[okami125]

It depends on what you need a transformer for. Centroid's transformers have 83VAC secondaries. When rectified that gives 120VDC which is suitable for their older DC servo motors. There newer motors are rated for 180VDC so you can rectify 120VAC directly without a transformer.

Even though I'm supplying my machine with 4-wire split phase 240VAC which I need for my VFD, I didn't want to run all of my servo motor power from one leg as that would really unbalance the two 120V legs. So I added a 240 to 120V single phase transformer, and rectified that to give me 170VDC for my servo motors.

I did use the neutral and the two hots for my other 120VAC loads like fans and solenoids, but I made sure to balance those loads on both legs.

Right and that's what I'm attempting to figure out is with my servo's being 140v should I step it down or run overvoltage? the original manufacturer Milltronics ran 160vdc direct to the servo drives.

[tblough]

I guess it all depends on your risk tolerance. Someone put 140V on the motor for a reason. Milltronics seemed to be able to run them at 160V. If you are going to run the same max speeds and accelerations as previous, you will probably get away with running 160V.

Faster speeds or faster accelerations will generate higher back EMF and could cause motor damage.