DC Servo motors and voltage level thoughts

[Joe]

Hello,

I have a few thoughts on the DC servo motor voltage that need to have cleared up. I have read in the AllinOne install manual (and elsewhere too) that you should never exceed the nameplate voltage that is listed on your servo motors. We have a Bridgeport V2XT mill with factory SEM motors (for the soon to happen conversion to AllinOne) where the motor voltage on the nameplates states 112 volts (26 lb ins,), and the stock axis power supply on the machine powers them at 130vdc. I have all of the original manuals and prints on the machine and it is clearly spelled out in them, that these values are stock from Bridgeport. I was actually thinking or reusing the original servo power supply as it is so well built, and the machine had very few hours on it. If I do end up reusing I would be replacing the electrolytic capacitors first, (depending on what advice you guys can throw at me about using it).

So here is my question(s):

1) why would they be using "well" over 112volts on the power supply? (I could see maybe a little higher but it seems like 130vdc is quite a jump.

2) anyone use the stock power supply in their conversion, and are you happy? (with your decision, not life in general...)

3) If I choose to go with the Centroid cap and bridge combo (and ditch the Bridgeport power supply) I will need to go with a new main stepdown transformer as the factory unit has 90volts on the secondary side, (for the conversion to 130vdc in the power supply). Should bring the end voltage closer to 112vdc. Or would I not, and just use the same main stepdown and drive the servos with 130vdc. I guess I am wondering if there was a different control scheme in the old stock drives that took this higher voltage level into consideration, and the motors never really saw 130 volts..

Thanks for the help

Joe

[cncsnw]

I did a couple V2XT projects a while back. I used the original transformer (90V / 180V center-tapped secondary) with Centroid's CAPBRDHI rectifier board.

I figured that, if Bridgeport built it to run the motors using that voltage, and they have been running with it for 20+ years, then it is probably okay to continue doing so.

[Joe]

Ok, thanks for the input. I will probably do the same and retire the old power supply.

Joe