Centroid Community CNC Support Forum

Hello everyone! I own a very old shopot prt...it has Vexta motors...the vexta a6497 9412ktg . My motherboard bit the dust and Im upgrading to the Cerntroid Acorn. I also purchased a g540 from Gecko...its all arrived and I have done a successful bench test and have software set up. where I'm at now is I ordered these: DaFuRui(4Pcs-Male) DB9 Solderless RS232 D-SUB Serial to 9pin Port Terminal Male Adapter Connector Breakout Board with Case , DB25 cable, Gecko G540, 48V power supply
and need to wire the motors..I am far from an expert. I think others have done this...advice or direction to a post? I'm looking forward to gettiing it all running! -Doug

No report to include yet... I can provide photos if needed.

recommendations for different motors is appreciated too...to remove the old open loop steppers. maybe closed loop steppers?

Your bench test should include connecting motors to the drive and verify that they work. Can't remember the first (A) pairs wire colors on that motor, but the Second (B) pair is black and green

I realize those motors are 20 some years old and would consider replacing them…

True... and maybe even worse than being 20 years old, they are high inductance, so they do not perform well at speed. That said, Gecko products were designed for those old technology motors.

I no longer build stepper systems, that torch has been passed to Matt D. When I did, I always would recommend a motor upgrade. Just remember that you will need either a belt or gear reduction system, along with an adapter plate that fits the PRT to make modern motors work. I recommend NEMA23 motors in the 350-450 ozin range. Modern NEMA34 motors (~600 ozin & up) have too much torque for those flimsy old frames.

It's been a long time since I hooked up one of those motors. Oriental Motor built the steppers with six leads. Shopbot wanted only four leads. You probably have Red/Blue for one phase and Black/Green for the other phase (as Gary wrote). The 50V limit of the G540 can't force enough current through those high inductance windings to get good performance. You need steppers with an inductance of about 2.0 mH and a power supply of about 35VDC to get good performance from a G540. Also, make sure you use the proper current limiting resistors to keep the motors and drivers within Amp limits.

So...in the short term...I have gecko 203s...how could I hook those up to the acorn board to get up and running until I have time to source brackets and gear reduction adapters for nema23's...Use a d25 breakout board? for all four drives?

Best thing you can do is look over the docs here. Instruction for each and every step of your build process. Including schematics for your Gecko drives.

viewtopic.php?f=60&t=3397

thanks Gary...I appreciate the help with an old mahine