Dyna mechtronics DM3000 lathe , mach conversion

[m_c]

If you're relying on Mach for threading, then you don't need closed loop. Mach only needs, and can only handle a single pulse per revolution, which it then uses to control the Z-axis, so the spindle itself doesn't have to run closed loop. The spindle just has to maintain a relatively constant speed, to ensure things remain in sync.

If you are going to be using some form of external motion controller, then the spindle and feedback requirements vary.

[dazza]

Thanks for explaining that m_c
To anyone ,will this be sufficient running my spindle motor http://cgi.ebay.com/ws/eBayISAPI.dll...tchlink:top:en I would also use a braking circuit.
spoke to the seller yesterday and says the drive will be about 140v output due to 10-12% power loss on the bridge of the drive

But im unsure what determines a drive works with a brushed motor and not brushless and vice verser
some state there for one or the other and others don't mention it, my motors brushed .

[m_c]

To anyone ,will this be sufficient running my spindle motor DG4S 16035 Positioning DC Servo Drive Mach3 CNC | eBay I would also use a braking circuit.
spoke to the seller yesterday and says the drive will be about 140v output due to 10-12% power loss on the bridge of the drive

But im unsure what determines a drive works with a brushed motor and not brushless and vice verser
some state there for one or the other and others don't mention it, my motors brushed .

That drive should work. However you need to ensure you have an incremental encoder, that outputs a quadrature signal (usually referenced as A & B outputs). You'll need to figure out eaxctly what the existing feedback device is, to see if it'll be any use.

[Jonathan]

If you're relying on Mach for threading, then you don't need closed loop. Mach only needs, and can only handle a single pulse per revolution, which it then uses to control the Z-axis, so the spindle itself doesn't have to run closed loop. The spindle just has to maintain a relatively constant speed, to ensure things remain in sync.

One pulse per revolution is closed loop, just not a very good one! You don't need a position loop though, just speed. I'd have thought using an external driver with a reasonably high resolution encoder would be better since the driver will be able to do a much better job of holding the speed constant (and ensuring the average is exact) than Mach3 with one 1ppr.

But im unsure what determines a drive works with a brushed motor and not brushless and vice verser
some state there for one or the other and others don't mention it, my motors brushed .

If they don't mention it anywhere, that's surprising, but you can always count the terminals and look at the labels. In general, four terminals means it's a stepper driver, three terminals (UVW) means it's a 3-phase brushless driver and two terminals will be a DC driver. There are rare exceptions.

[m_c]

One pulse per revolution is closed loop, just not a very good one!

It's not closed loop.
To me closed loop would mean using that pulse to control the spindle, but it doesn't. It simply uses the pulse as a reference for syncing the Z-axis.