Inverter/3-phase drive for my S7

Following on from my motor problems a couple of weeks ago, and having regard to the many helpful comments here, I took the plunge and bought a
CL750 1HP motor and inverter set from Newton Tesla*, cost just over 400. I could see it would have been cheaper to buy the parts separately, but the time and trouble to locate the right parts, learn how to connect and program, and to make an enclosure, would have been rather burdensome.
As it was, the NT kit was an absolute breeze. It took less time to fit than it took me to remove the old motor (if I say the longest part of the operation was making holes in the lathe stand to fix the inverter box, you'll get the idea). Motor plugs into inverter, inverter into mains, and Robert is your mother's brother; everything worked first time exactly as it should. Only used the lathe for a couple of hours so far, but already I can see that the benefits of the huge speed range is tremendous; can twizzle the speed down at the touch of a finger if I detect chatter with a boring tool without interrupting the cut. If I had known it was that simple I would have done it years ago.
A footnote - the old motor was gunged up with a mixture of oil and wood dust (had done a little wood turning years ago) which had seized the bearings solid. I guess the jolt it got must have disturbed the grot somehow. It cleaned up OK and works again, but in view of the advantages of the inverter drive I have no regrets.
A footnote to the footnote - looking at the motor spec plate, it turns out it was only 1/2 HP (IIRC the spec for the S7 is 3/4 HP, but I suspect this was a replacement the previous owner had fitted). I always thought it was a bit light on power but it was virtually impossible to see until I removed the motor. OTOH, I guess if I have any screw ups, they could be more disastrous....
David
*Usual disclaimer.
--
David Littlewood

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Hi David, pleased to hear that you are up and running again and enjoying the ability to "twizzle the kn... sorry switch". While I always enjoy the challenge of getting things to work I must admit that sometimes I also like to bask in the pleasure of buying something which has been well designed, well built and does exactly what it says it will without any fuss or bother. Somehow it reduces the pain of putting my (slimmer) wallet back into my pocket. I'm sure you will enjoy the facilities you now have and I have certainly found that thread cutting up to a shoulder is now something I do not try to avoid at all cost but rather enjoy the ability to slow the process down at the end to match my capability.
..............

To avoid this issue I run the drive belt on mine fairly loose so that the drive is OK in normal use but would slip if you were unlucky enough to have a major "scew up". Not any good, I know, if you intend to remove large amounts of metal in a short time but for normal turning it produces a sort of "safety net", particularly at slower speeds. If you run the saddle into the chuck at 2200 rpm it won't help much :-)) Enjoy your new found control.
Best regards
Keith
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Polytechforum.com is a website by engineers for engineers. It is not affiliated with any of manufacturers or vendors discussed here. All logos and trade names are the property of their respective owners.