Hi,
I priced some DC servos for a customer, spares for his aging plasma table and I was shocked at the price and for 100-200w servos at that!

Have you seriously looked at the prices of AC servos and drives. I don't think I would be going for the cheapest Chinese stuff but Delta is a very good
brand and a good compromise between price and quality.

If I'm not mistaken they'll make DC servos look like yesteryears expensive tech.

Craig

Craig, yes on a recent large Wadkin router,
  I looked at a system from zapp automation, but the complete system with new motors cost £2800 plus vat (more than the machine was worth).
There was nothing wrong with the sew DC servos fitted to the wadkin, as it had come out of a school and for all intents and purposes never used.
So to retrofit it with cncdrives equipment cost £600, much more acceptable to the customer!
There are still a lot of PMDC system, IE anilam bosch machines out there which is where I pick up work.
  I shall at some time look at the ac systems especially if the donor machine has knackered motors.
Horses for courses I guess.

Hi,
yes if the existing motors are good then new drives would certainly be the way to go.

I had not played with a decent AC servo until fairly recently when I bought a secondhand 1.8kW Allen Bradley servo and drive.
It wipes the floor with any DC servo I've come across. The tuning software has a database of electrical, thermal and physical characteristics
and even magnetic characteristics including saturation and hysteresis. All manner of control modes, pulse, analogue, all manner of modes torque, velocity
and position, indexing both speed and position, incorporates its own limit switches, able to program any number of digital and/or analogue performance
indicator outputs, programmable following error and the list goes on. I'm still learning about what they can do.

Many of the Eruopean and American brands are very expensive, as I say Delta (Tiawainese/Chinese) is a good compromise. About $1000US for a 1.5kW servo and
drive with a 20 bit absolute encoder. Makes mincemeat of DC servos.

Craig

Ah yes but that would be a nightmare for me!!
I'm a mechanical engineer with fair electronics skills but practically zero software ability or understanding, I would get tied up in knots trying to set that lot up!

Tony

well I have received all the answers to my questions on the cncdrives forum within 2 hours, they were answered by cncdrives themselves  so I'm happy with that !!
I guess its all about using the correct communication channels.
  Tony

Hi Tony,
you sell yourself short...

I'm a mechanical engineer with fair electronics skills but practically zero software ability or understanding, I would get tied up in knots trying to set that lot up!

The software that accompanies these late model devices makes it considerably easier than you might imagine and certainly much easier that setting up and tuning
a PID loop.

Craig

Go to the Cncdrive forum for help with this.

Balazs is very active there.

Their answer will be: "We don't use Mach3"...