10ee VFD Conversion

Having read a ton of the commentary on the lathe, I'm not sure why anyone puts a 7 or 10 hp motor in this machine. Of course I'm just a hobbyist, so I'm not all that aggressive. However, I've yet to stall the lathe when machining something. It just keeps turning. 5 hp seems a good compromise especially with the back gear.

Best of luck with your lathe.
I could be wrong but it seems like mine had a 3hp motor in it. It was a 1952 MG machine. Used it for about 5 years and the only problem I had was a burned coil. Smooth running machine.
 
  • Like
Reactions: Z2V
I could be wrong but it seems like mine had a 3hp motor in it. It was a 1952 MG machine. Used it for about 5 years and the only problem I had was a burned coil. Smooth running machine.
Yeah...my thoughts exactly. Maybe they are going big without the backgear??? IDK
 
Yeah...my thoughts exactly. Maybe they are going big without the backgear??? IDK


Well, its all about torque, not HP. The original 10EE drive developed way more torque at low speed than a comparable 3 phase motor. The electrics on these old machines are impressive. Hence the need to go bigger with 3 phase/VFD over the 10EE DC drive.

Now, eliminating the backgear is a huge torque problem as it gives a 6:1 advantage. Even with doubling the size of the 3 phase motor, there is still a considerable disadvantage without the back gear.


Now, there is room for discussion on how much torque you really need. If you want to take heavy cuts on ten inch diameter tool steel parts, the maximum torque is needed. Don't do this sort of work, then a bit smaller drive is fine.
 
3hp DC with back gear is okay, that is what my 56 WiaD machine is, I looked at a 7 hp machine with no back gear, Fanuc controller, very expensive refit , it was a complete dog below 500 rpm, you could stop it with one hand. On my 56 I can turn 8 rpm and there is no way I could stall lathe it is a beast, with 3 hp DC. I think anyone who has used a well tuned original machine would cringe if they had to use a machine with no back gear, I don't care how much hp it has. Karl is dead on abut the back gear.
 
3hp DC with back gear is okay, that is what my 56 WiaD machine is, I looked at a 7 hp machine with no back gear, Fanuc controller, very expensive refit , it was a complete dog below 500 rpm, you could stop it with one hand. On my 56 I can turn 8 rpm and there is no way I could stall lathe it is a beast, with 3 hp DC. I think anyone who has used a well tuned original machine would cringe if they had to use a machine with no back gear, I don't care how much hp it has. Karl is dead on abut the back gear.
Thanks for the info...about the gear box. I have found that I am missing the smallest gear of the 4. while I am awaiting a callback from Monarch...Any ideas where I could find a gear blank? I can bore and broach one and suppost I could make one but would rather not.
 
Thanks for the info...about the gear box. I have found that I am missing the smallest gear of the 4. while I am awaiting a callback from Monarch...Any ideas where I could find a gear blank? I can bore and broach one and suppost I could make one but would rather not.

I would ask the boys over at Practical Machinist Monarch board. Lots of guys over there have 10EE. Someone will likely have spare parts, or watch ebay. Some parts from Monarch are reasonably prices others are absurdly high. That said they would well made if they have them.
 
Boston Gear will have one that needs the arbor bored
 
I'm well into this project having almost completed the 15/16" aluminum adapter ( tomorrow the 1.125" reamer comes). After reaming I will slip the adapter over the motor shaft and locate the 1/2x13 holes on the "C" face , and drill the holes. I still have to ream the sliding drive gear to 1.125" and broach it to fit the motor shaft (1/4 keyway, sliding fit). If this build is successful I'll post pics, detailed order of ops, and cost.

So far things have gone well, almost too well, other than one misplaced hole which I repaired it's been easy. I'm scared. Usually I have to do things at least twice and maybe three or more times before I get it correct. Stay tuned.

All that being said I have a lot of leftovers to get rid of: tubes, a 5hp DC motor, a lot of electronics and electrics I know nothing about. Anyone here interested before I go to CL or eBay? Never used eBay to sell though I have bought there.
 
Can someone help with this....I measured my centerline of the 2 shafts and it is 3.000" . The big gear is 72 t and the small gear (the one I need) is 24 t.

Am I correct with this thought pattern....find a gear that meshes with the one I have in order to find the pressure angle and/or pitch diameter? Just beacause it is a 24 tooth gear doesn't mean that it will mesh with the one I have right?
 
yep, you going to need that. Machinery handbook has a good section on how to measure a gear and get the numbers.
 
Back
Top