They also have tuning software for the drives. The simplest and cheapest solution would be to re-use the DC motor but replace the Resolvers/Tacho with differential encoders and then use DC drives with Step + Dir.ĬNC drive makes 160VDC 35A drives with Step & Dir inputs which will work nicely with UC300. They will most likely be 200A drives if the larger motors or 160A if the smaller ones.
The drives will be the same Badged Analim but the will most likely be made by Glentek. They could have Resolvers or Encoders with Tacho but most likely Encoders but they will be 5 wire single end encoders and around 1000ppr. Often they will have a voltage rating of around 36v per 1000rpm so 110Vdc will give 3100rpm. The motors will most likely be badged up Analim but they are actually made by SEM and I'd guess around 3.5Nm -4.5Nm (30-40 IN-LBS) 4000rpm Max voltage 120-140V and will running at 100-120Vdc. Thou i think the Bridge port size machines used slightly smaller motors.? The Big Mill I've got had the same controller and probably similar type motors and drives. Spindle motor drives the spindle via a variable-speed gearbox so the control system only needs motor on/off control, not speed.
Table size is about 36x12" and the Z axis drives the quill rather than the table.
Any back-of-the-envelope guesses? I'm currently thinking something like 1.5KW/6Nm absolute servos with matching drivers (absolute as this machine has a mechanical limit switch and I'm not sure how repeatable homing would be). I'm happy to give him a few options for the control electronics (UC300+PC, dedicated Chinese controller (SZGH?) are likely options) but not sure about motor sizing for a machine like this, at least to be able to consider ease of replacement and costs. I haven't had the covers off the motor mounts (apparently belt-drive to the feedscrews) to look at mounting arrangements, etc, to get an idea of ease of replacement but that might be easier than grafting a new motion controller on to the existing drive electronics (assuming that that's not where the fault is!) I have considered leaving the motors and their drivers in place (I believe 10V analogue) but not having any idea what the servo feedback is on these machines and given the reduced choice of control options for analogue, I'm not entirely happy with that. I'm trying to get some idea of what to use for the control system and motor sizing so that I can give him a rough budget and estimate of work involved. I believe that it uses DC brushed motors, no plate on them, and I have no idea what's on the back of them. We started kicking around ideas for a refresh of the machine.
The current fault on it might be as simple as a dirty connector somewhere, or it might be something on a control board which would probably be uneconomic to replace.
Which is more than can be said for the control system - it's built-in PC still has a floppy disk drive and the whole lot is probably 25 years old. Had a call from a friend earlier - "my CNC mill ain't working!" It's a Bridgeport-style vertical mill, built by Ajax, and by the looks of it, a decent machine in decent, little used, condition.