New here but I have lurked for a long time to figure out how to go about doing this. First I am pretty terrible with electronics and this is all completely not in my realm of comfort but screw it I am going for it anyway.

Unfortunately the memory in my old lathe has started to give out and I decided to go for a mach conversion.

(stupidly I never took an overall picture this is a real old picture of it after someone gave it a terrible gray paint job)

What i plan to keep:

The Zebotronics stepper motors, they draw around 36volts and are 3.5 amp

The Proximity Home Switches which are a 12v system but I still have very little idea on how this is going to work out
The circuit breaker for the ac line in

The fuses on the AC line
The AC powered fan under the motor/spindle housing and the other AC fan in the computer housing

What I plan to replace:

The motor drive board to get something more modern in it
All the stepper drives
The breakout board
The monitor and all the controls
Eventually modifying the cabinet to use flood coolant
Eventually modifying the cabinet to be fully enclosed

What I am using for the conversion:

A KBMG-212D Regenerative motor drive
A Gecko G540 board to control everything
A smooth stepper board so I do not need to use old XP
A 48 Volt power supply 8.4 amps
A 12volt wall charger to use to power the home switches
A 1 signal per revolution tachometer sensor for threading with mach
an additional outlet from my gecko box for later coolant modifications
I have a windows 7 32 bit professional tower, that I had for college and havent used in years.
It has 1 gb of ram, 500gb 7200rpm hard drive, pentium 4 3.something ghrtz, plenty of power for it
Some usb extensions to easily plug in flash drives.
I am looking at picking up a usb pendant from VistaCnc
I have a 10" multitouch monitor to replace the old cvt screen
I also have a touch screen mouse/keyboard combo which is small enough to fit up top with the screen coming for computer controls
I hope to just modify the existing face plate up top and cut in the new sleeker displays and keys, there is plenty of room in the box for what I am planning.



Things I know about the machine now:

Machine runs on 230 VDC single phase
The motor is 1/2 hp dc shunt motor drawing around 160 vdc with the stock board, and a field voltage of 180ish vdc, draws around 2 amps under load as far as I measured.
3 zebotronics steppers, not entirely sure on what sizes they are but they draw 3.5 amps max and run around 36 volt peak at rapids.
3 proximity h.e.s. style limit switches running at 12 volts
The tool changer has a 60:1 Ratio that I need to somehow code in down the road but I am completely uneducated on that portion as of now.
The stock spindle speed was 3000 rpms
The stock rapids are a bit over 100 ipm (all metric as of right now)
About what I know

First attempt is to wire up the motor drive board. Before I did this I was not entirely sure if it was a pm motor or a shunt style. I originally wired it as a pm motor because it is easier.

I made sure that all the tabs were set correctly for 230 VAC coming in, and had the output set for 180 VDC. I plan on using the Gecko g540 to control the KBMG-212D board eventually off its 10v setting but decided to wire up the 15v potentiometer to try and get the motor driven by something more modern.

Wiring up the potentiometer I first put a jumper between en and com to get the board to run, then I connected the potentiometer to run the motor in the forward direction. From left to right it was Com, Sig, 15V+ wired into the potentiometer.

Set the amperage jumper to 2.5 amps and put some power into the board to make sure the potentiometer was changing the voltage coming out at the motor end.

I then had to figure out which was hot and neutral leading to the two brushes on the motor, both wires were red so I had to run the motor and put a voltage meter on it and see which way read positive and then reversed it to make sure it said negative when I had it backwards to figure out which was hot and neutral.

Wired them up to the board and tried to drive it... I heard the power going into the motor and it spun slightly, needless to say I was disappointed but then started looking for more wires and found the two that made the field for a shunt motor. I put connectors on these two wires and plugged them into the f slots, didnt know which was which, because they were the same color again, but just went for it. First plug in had the motor spinning the other way, figured I should just switch the field wires again and it did the trick. Started spinning correctly and had good power. I put a reflective strip on the spindle and read the speed with my tachometer and seen that full out it was running at 3400rpms which is great because I am putting 20 more volts into it then the old board could.

Very successful for day 1, Next up will be wiring in the ac fan and an estop switch on the motor side, as well as mounting the new motor drive board. I decided to keep the bus bar in there and want to use the wires already run through the body to handle all the connections from the gecko g540 board, and the new tachometer that I need to put on the spindle for threading.

Pictures of the outdated spindle control



(old ohms resistor under motor)

(picture of the top brush it still looks to be in good condition)



Pictures of the wiring and new setup

(just the drive board with jumpers set correctly for my setup)


(AC line coming in from the other side of the lathe)

(AC side wired in )

(potentiometer and jumper wiring)

(full wiring of the board with the shunt motor field wired in on the bottom left and the motor outputs on the top left)

A small video of the first bit of success

(lets see if this linking works)

Next step is to setup the mach in my computer and try and get the drive board going with the steppers, then stripping out the stepper control cabinet to put in the new components.