Maho MH400 P servo motor

I am getting a Maho MH400 P, that I want to use as a manual mill, or I as I have been saying, in "electro-manual" mode, since I want to enable the electrical stuff to allow the hydraulic tool change and clamping of the feed axis movements.

I just posted my hydraulic questions in a separate thread. Assuming I get the hydraulics working which, via some means I don't understand yet, I think just "clamps" the various axis screws, I will eventually have feeds on X, Y and Z, and maybe even quill feed.

But those are all driven by one servo motor.

Attached is a pic of the mess at the back of the column. The servo motor is the grey lump in the middle of the tangle of wires. I didn't get a close up of it. In other posts I've read that Maho used DC brushed motors, with an encoder or resolver of some sort.

I did get a nameplate photo, which with Google Translate tells me it is a "servo motor ??? direct current". The nameplate has two 85-ish volt ratings, at 14.4 and 22.2 amps.

Can I buy a DC drive (like something from AutomationDirect), rated appropriate for the motor (22+ amps?), and use that as a speed control, to just use the original motor as a variable speed drive motor for the axes?

Or is there more to it?

Or is there a more modern, drop-in replacement path I might be better going down?

Thanks for any help or hints,

--Jon



(My other hydraulic post hasn't appeared yet... pending approval I guess.)

I have some experience with an 800p but I can't tell you if a replacement DC drive will work. I would think so. The issue is going to be feeding at slow enough rates and in encorporating the servo feedback so you can position it accurately. Does it still have its TNC 132 dro/control?

There are 3 electromechanical clutches which direct power from the servo to each screw you will need to run those, originally it only powered one axis at a time.

Also speed shifting on the 800 was via solenoids controlling gear shifting. Hydraulic pump and reservoir should be round the back of the column there near the servo. Clamps act directly on the ways not the screws.

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Thank you.

rblalexander said:

The issue is going to be feeding at slow enough rates and in encorporating the servo feedback so you can position it accurately.

Click to expand...

The MH400 is significantly less complicated than the photos I've looked at of the 800's. This servo motor does have a huge timing belt / pulley, which I suppose is how they reduced the top end 3,000 RPM of the servo down to useable speeds for the feeds.

I don't know if I'm going to be concerned with getting servo feedback, since I'm really trying to convert this into a (simple) manual machine. That's why I was wondering if just a DC drive might suffice.

rblalexander said:

Does it still have its TNC 132 dro/control?

Click to expand...

No, long since amputated. I didn't study a lot of the cables when I was looking at the machine, but I think whoever cut off the controller box, also just cut all the Heidenhain scale wires too. At least I know how to solder on the connectors I need to get those working for a DRO.

rblalexander said:

There are 3 electromechanical clutches which direct power from the servo to each screw you will need to run those, originally it only powered one axis at a time.

Click to expand...

Ah, thanks. I wasn't sure what the actual mechanism was. A clutching mechanism makes sense, now that you mention it. Duh.

rblalexander said:

Also speed shifting on the 800 was via solenoids controlling gear shifting. Hydraulic pump and reservoir should be round the back of the column there near the servo. Clamps act directly on the ways not the screws.

Click to expand...

Thankfully there is no sophisticated shifting on the 400. I think the feed speeds were just by potentiometer. The spindle and arbor just use a mechanical Reeves drive and two speed range manual knob. I have looked at quite a few pictures of 800-class machines, and that gearbox and shifting mechanism would be above my pay grade to dive into.

I think I'm gaining a grasp on the hydraulics now (separate thread), and the components are starting to make more sense. Except of course the electromechanical clutches that I completely missed. Thanks again for that!

--Jon