# CMT Ursus 250 Repair: 4) It Is Alive!



## RobinHood (Feb 9, 2022)

Big step today: after gutting all the electrical - mainly because I am not running it on 440V, and because I have no wiring diagram for this vintage of the Ursus 250 - I hooked up a motor contactor with overload, a light switch to activate the 120V coil in it and 3 Phase, 240V power from my 10hpRPC. The lathe has a 10hp motor, so I figured that under no load it should run the motor fine. Removed all the belts and gave it a try. It worked.

Next step was to put oil in the sump, connect the belts and run the lathe out of gear. In that configuration only the input shaft and the second (brake) shaft turn. Third shaft and spindle are not engaged. The oil pump is driven by the input shaft. This allows full flow lubrication, even at low spindle RPM. Started up the motor - no oil flow. The motor was turning in the wrong direction. Switched two leads around and presto, oil flowing liberally (as indicated by the sight glass) everywhere as the motor / oil pump is now turning in the correct direction.

Time to put top cover on as there will be a big mess once the other shafts are engaged. The clutches had been set very weak at assembly (on purpose to facilitate adjustment by trial). Engage the lowest gear and the clutches were slipping too much. Stop the machine, disco power, open clutch access plate and adjust both FWD and REV clutch by a couple of notches. Close cover. Connect power. Try again. Yes, lathe runs in lowest speed - 23 RPM. Test all other functions like power feeds, threading half nuts and run a bunch of speeds/feeds in the QCGB. All ok. Apron oil pump works as well (sight glass confirms it).

Try some of the higher speeds. I knew that the clutches were still going to slip, so adjustment was as above for each of the 18 speeds. The top placarded speed of 1000 RPM - which is based on the motor running at 50 Hz in Europe (I run it at 60Hz, so the top speed is higher), blows the 30A breaker of the RPC circuit. There is a lot of inertia at the higher speeds. If I am really, really gentle feathering the clutch, I can get it to go without tripping it.
It works fine (no RPC tripping) up to the second highest speed - 780 RPM placarded.

More realistically, I am going to be looking for a 20hp RPC to run this and all the other machines going forward.

Here is a video of the machine running at about 78 RPM. The “spaghetti salad“ is the result of the gutting. I think the control circuit will work as is. The 440V to 120V/30V transformer was pulled out. It will be replaced with a 120V to 30V one as I am feeding in separate 120V, fused, control voltage. The 30V is required by the electromagnetic brake rectifier circuit - not connected yet as I am still testing and developing the circuitry. The door safety switch and brake control circuit will be wired in last.









						CMT Ursus 250 First Power-Up
					

Watch "CMT Ursus 250 First Power-Up" on Streamable.




					streamable.com


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## PeterT (Feb 9, 2022)

Nice. Smooth a silk. The neighbors will just have to get used to occasional light dimming.


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## RobinHood (Feb 9, 2022)

PeterT said:


> The neighbors will just have to get used to occasional light dimming.


Already got that feedback from my better half… was wondering what I was doing out in the shop this pm...


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## Dabbler (Feb 9, 2022)

beautiful!


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## Susquatch (Feb 9, 2022)

RobinHood said:


> Yes, lathe runs in lowest speed - 23 RPM.



O.  M.  G. 

Be still my heart! 

Very Nice @RobinHood ! I love it!


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## Sergei Slovenija (Jun 18, 2022)

RobinHood said:


> Time to put top cover on as there will be a big mess once the other shafts are engaged. The clutches had been set very weak at assembly (on purpose to facilitate adjustment by trial). Engage the lowest gear and the clutches were slipping too much. Stop the machine, disco power, open clutch access plate and adjust both FWD and REV clutch by a couple of notches. Close cover. Connect power. Try again. Yes, lathe runs in lowest speed - 23 RPM. Test all other functions like power feeds, threading half nuts and run a bunch of speeds/feeds in the QCGB. All ok. Apron oil pump works as well (sight glass confirms it).



Wow! My URSUS 20 arrived the other day. There are no instructions. Trying to figure out what oil level is needed. The oil pump and oil intake pipes, the glass pointer, hinted at a "dry sump" circuit. But there was no certainty.

Tell me, how many liters of oil did you need to replace in URSUS 200? I believe that mine and the version of the lathe will be 95% the same, in terms of filling volumes.

I requested a manual from the manufacturer, but my hands itch to do maintenance and start the machine)


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