Monarch 10EE rebuild 10Hp VFD no backgear

Karl_T

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I bought my second 10EE a while back

After playing with the existing DC motor and drive, I gave up on repairing it. I did not try super hard, not too excited about maintaining an antique system. So all the old stuff got ripped out.

I have another thread where I got help with motor and VFD selection

My first 10EE lathe used a 5hp 3phase motor and VFD with a backgear. the machine has worked WONDERFULLY for 20 years now.

For this build I decided to go with a larger 10 Hp VFD rated motor to give low end torque without the need for a backgear. Simplifies the build quite a bit.

Here's pics of yesterday and today's work. had to get tricky to put the motor in place. made a "U" shaped fixture to hoist the motor so it could tuck inside the lathe cavity. the entire lathe is on a pallet truck to move left - right. the hoist is on a rail to move in - out.

yesterday, built a little fixture to hold a 5 turn potentiometer on the existing speed control knob. It is not quite assembled - I will replace the opaque plastic tube with a more flexible clear 1/4" plastic tube and clamp in place. This keeps the pot from being too rigidly attached and allow the operator to feel pot end of travel without breaking it. Soldering of wires will wait until all mechanical work is completed.
 

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markba633csi

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Deek did a nice conversion on his:
 

Heychris

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I completely agree with your decision. I've done VFD conversions on several lathes. No need for backgear. Interestingly, I noticed an article about a new motor company turntide. They have a great motor comparison chart. I wish the new motors were already available. I'd consider one. For now I'm doing a 5hp motor and VFD
 

Karl_T

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OK, lot of work last couple days, not much to see.

Got all the original wiring stripped out along with all the original conduit. Only a few components are going to be re-used. Found the three wires for the forward/off/reverse lever and labeled them F C R for forward common reverse. EXTRA CREDIT - I could not remove the plate shown in the pic. It was still tight after removing the four slot head screws. Beating on it with a chisel etc. was no help. HOW to do it?? Also there are five conductors here, what could the other two be for?

I will also re-use the stop start pushbutton and wire it to the main power contactor. Found two wires for the coolant pump with the third wire taped off so it must be a single phase unit. The switch for this is in a terrible position - on the back side of the headstock. Think I will change that.

Got the spindle motor plate drill and tapped to mount the motor and have it all installed. I had lost one of the rubber mounts for the motor plate and had to clean the whole shop up to find it. So now I got a nice neat shop as part of the deal.

The project will go dormant waiting for parts.
 

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Beckerkumm

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Thanks for the thread. I'm doing a vfd conversion on a Smart Brown 1024 which has a 3.6-1 clutch and a 7.85-1 back gear so a four pole 5 hp motor works for me. Did you go with a vector duty 6 pole to get the range needed with no back gear? Dave DSCN3903.JPG
 

Karl_T

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I was originally focusing on getting an 8 pole (900 RPM) motor, see link to my previous thread. I was convinced to go instead for a 4 pole (1800 RPM) VFD rated motor and pulley it down more.

 

Beckerkumm

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Looks basically the same but TEFC rather than TENV. Will you need to put an auxiliary fan on the motor ? I've seen computer fans activated when the vfd drops below a set hz to help cool the motor. Since these are meant for a wide range I don't know if that is necessary. Sweet motor. What range do you intend to run it? Sorry if you answered earlier on the other thread. I gave up reading through the crap answers you got. Dave
 

Karl_T

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I will keep trying slower and slower while threading to find the bottom end. probably start trials at about 5 hz. If that works try 3 if not try 8, ya da ya da.

no plans to add a fan
 

Beckerkumm

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I don't think you will find a bottom end. You can go down to .5 hz and still not be able to stop the spindle. Whether the finish suffers when the hz are that low is a different question. I think you will be fine but it is nice to have someone actually verify it. Dave
 

Karl_T

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I had ordered a P1 series hitachi VFD a couple weeks ago. Just talked with drives warehouse - its now on back order. So I am going with the WJ200 drive.
 
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