CW #23419 16" x 60"?

[Tiger_one]

The un-named eBay VFD died, or will not start motor anymore. Error OC_u, which is over current. I set start acceleration to 120 seconds, made no difference.

I measured wild leg at 35amps at 30Hz before it died. Didn't get a chance to test Pony as second choice for VFD before it quit.

Shaft diameters are different on Pony vs Monarch motor, so sheave will not interchange.

Looking at my options for turning in the Rong Fu mill to finish my Z-axis cnc conversion.

 

[Cal Haines]

I don't understand. Were you using the VFD together with the RPC? If you're running a VFD, there's no need for the RPC. You use the VFD to directly drive the spindle motor.

Cal

 

[Tiger_one]

I don't understand. Were you using the VFD together with the RPC? If you're running a VFD, there's no need for the RPC. You use the VFD to directly drive the spindle motor.

Cal

Sorry, I'm not very clear on my paper work explanations.

I'm trying to get this lathe running, so will try and put the Pony motor in, but was unable to test it initially. Seller (VFD)responded and gave me some parameters to start the lathe motor but really really slow acceleration.

I had 50Hz set as rated for the motor, however it throws over current fault beyond 36Hz no matter how slow it starts. T3 leg is beyond 35amps. So, something gone amiss with the lathe motor.

So tonight, I hooked up the Pony motor (sans all caps) to VFD and bingo runs to 50Hz and starts quickly, course only load is belt to table saw startup motor.

Checked the Legs for current and all 3 around 17amps. Motor is rated 230v @ 26amps 60Hz and 1740rpm.

At this point looks like I need to scoot (huge crowbar) the lathe out from under the upstairs steps so I can have room to pull the motor and swap the Pony in.

Shafts are wrong size, will have to bore the sheave on lathe motor to 1 3/8" as it is 1.225".

Recon how much the OEM motor weighs? I'm expecting 250lbs or more.

 

[Tiger_one]

Before pulling motor, noticed the connections at motor were burned and looked bad. I trimmed the ends of motor wires and connected the leads again (new #10 awg).

VFD ran it up to 40Hz but motor sounded terrible. Checked legs for current, 26, 35, and 45. Shut it off.

Pulled motor. Anyone want a slightly used Monarch 7.5HP engine, otherwise it is going to scrap. Might check with vintage people and see if they are interested.

Now to fab a mount for the Pony motor and get the sheave bored.

 

[Cal Haines]

Is the old motor also a 1750 RPM motor?

Cal

 

[Tiger_one]

Is the old motor also a 1750 RPM motor?

Cal

No. Old was rated 1450rpm. Was turning 5.75" sheave to 11" clutch sheave on 35" centers. Calculated RPM at 11" sheave 758rpm.

I decided to go with a 5.125" (1-3/8" bore) 3 belt sheave I found on eBay, which calculates out to 810.7 rpm with new motor turning 1740rpm. Sheave centers will change cause the new motor mount is shorter, to 36.25" and take 3 new BX95 v-belts (actual 98"). Turned out to be OEM Caterpillar belts.

Now to use my X and Y CNC Rong Fu to layout the new holes for the motor mount. After I get the motor mount plate out of the lathe. Cleaning everything I take off.

Oh, I drained the 30wt oil today and replaced with ISO68.

 

[Tiger_one]

Got the motor mount plate loose! Two back pins were not too bad, used a rod and hammer. Front pin would not budge, fabbed a tool to fit behind one side and pushed it out with my puller. Took all day fabbing and trying and failing, modding it. 2"x4" is to hold the plate out and get the adjustment eye bolt out of the way of the puller.

Does anyone know if the motor mount plate will come out the end hole or do I have to jack up the head and slide it out?




P.S. Got it out!
Trick was to remove the two rear pivot blocks (set screw behind lathe) to make room to pivot the plate around with nose sticking out side hole. AND

The protruding part of lathe bottom was in the way at front left corner so screwed the two front leveling screws all the way in and this allowed the plate to pivot with the nose going under the protrusion.

 

[Tiger_one]

Rong Fu mill was too small to get all 4 holes, but I got the important 2 at front of motor for alignment, then laid the other two out and manually drilled.

Tapped M12x1.75 and waiting on bolts to arrive. Probably will not go in the motor from topside as the motor is in the way. Probably screw them into plate and cut heads off install motor and put nuts on.

 

[Tiger_one]

Belts came in today, up and running. Will be making chips later. VFD is working perfect. Less than 11amps on each leg to 10HP motor with lathe out of gear, less than 12 amps at full speed in gear (487rpm). I will rig up a tach and see what the real speed is.

Happy camper at this point. Thanks for all suggestions and questions.

 

[Tiger_one]

Tried tuning the lathe with 12" piece of 3.5" OD pipe.
Started with nearest the head 3.360" and at end 3.348".
Jacked up the head with front leveling bolts couple turns at a time.
Stopped at head 3.3415" and end 3.340".

The new (Pony) motor is very loud with bad bearings, will pull today and replace bearings. Never noticed before with all the noise, now lathe is much quieter.

Truing the lathe

 

[Tiger_one]

Bearings in, major difference, motor is very quiet on lathe now. Very happy, like getting a new lathe, can hear the lathe now, like never before.

Finished the Z-axis on the Rong Fu, this is what started this whole thread when my lathe died.

I like to use stuff I have laying around, so 1999 Harley twin cam gears were put to use after lots of head scratching and trial and error with some other options.