How to determin the operating paramaters on an unknown servo motor.

[circlecn]

Hi Guys, I am relatively new to CNC and am building some CNC stuff. I acquired a beautiful servo motor many years ago. It came from HP mainframe equiptment (There is an HP label (0725-69012 handwritten on silver tag) but I haven't been able to find any trace of it on the net). From my limited knowledge of servos it is brushless. It has a built in encoder. It weighs at least 15 lbs. I would love to use it. I would put on a new encoder -I guess- on it. I hooked it up to 24 volts - spun beautifully. How would I go about determining its optimum operating voltage?

Thanks for any help on this.

Kent

[Al_The_Man]

Originally Posted by circlecn It weighs at least 15 lbs. I would love to use it. I would put on a new encoder -I guess- on it. I hooked it up to 24 volts - spun beautifully. How would I go about determining its optimum operating voltage? Kent

If you hooked up 24vdc I doubt if it would spin if it was brushless, unless you have a BLDC driver amp. If it was straight DC then it was most certainly brushed, two ways of determining voltage required is to estimate the maxium rpm, for a brushed motor, it rarely goes over 3000 unless a specialty.
so you can either apply a voltage and measure the rpm, it will be directly related to speed, so if 24vdc gives you 1000 rpm then it is roughly a 75vdc motor.
Or you can spin it a known rpm and measure the generated DC, and do the same math.
If you need any other specs, I think I have a previous post on finding them emirically.
Al.

[circlecn]

Hi,

I will do that as soon as I can figure out how to measure the rpm.
I will report back.

Thanks
Kent

[Kipper]

Al would these be on your list? I came home tonight and these were on my doorstep (my mates a scrapper...metal that is and I asked him to keep an eye out for some stepper motors....I even showed him 20 of them so he knew what they looked like...Anyhow he supplied me with these little cuties) I was thinking of a Gecko driver system as the black Al looks cool from what I can gather these are 18V (too low?) the gearheads are incredible with no discernable backlash(havent worked out the reduction yet) i'm kind of hoping to build a large ish router with them once I get my mill converted. If there's an emperical or numerical list to assist then just point me to it :beer:

[Al_The_Man]

I don't have any info on those but they obviously appear to be DC brushed, a rear shaft that would accomodate an encoder, If 18v max then you need compatible drive.
The ratio should be easy to observe by counting the turns on the back shaft until the front does one rev.
Al.

[pastera]

They are listed on the Maxon page with gear head info in the catalog

The motors look like 24v units by the part number

Aaron