Surface Finish Issues On 12x36 (long Post) + Kb Electronics Vfd Install

The saga continues--Mostly in a positive fashion.

I have been debating about starting another thread about installing and setting up the VFD & 3 Phase motor on the 12x36. I have decided, that the VFD install actually falls into the surface finish realm, and therefore am leaving it as one thread. I will attempt to rename the thread to include VFD install in it in case anyone else attempts this.

As a pilot, I would rather fly an instrument approach to minimums with a 20 knot crosswind & one engine out than mess with electric & electronics--I'm not afraid of it, I just don't enjoy it.

Anyway, I obtained the IODA board for the KB VFD and have it installed. I followed MKSJs programming and setup notes that he so generously provided, and was able to get the motor spinning nicely using the VFD controls. Then the fun started. My next challenge was to set up for remote operation. Remember, I am electrically challenged (severely). I hooked it all up as best I thought I knew how. I couldn't figure out why the motor wouldn't run. I read & reread the manual--which is very good--not written in Chinglish. I was just not clever enough to figure out which of the situations I was attempting to set up. I called KB tech support & got through to a tech almost instantly. He first asked what I was using the drive for. I told him a metal lathe and his response was "That is too much drive for a lathe--kind of like putting a jet engine on a Toyota Corolla". After we had a good chuckle, he walked me through the setup, & wished me luck.

So, back to the bench. Let me interject here a bit--I have the motor & drive on a workbench. I have been using jumpers to simulate the switches. That leaves the lathe contactors completely out of the equation, for now. OK, moving on. I reprogrammed the parameters per the techs instructions, & NOTHING!!

Started over, did all the programming again, & checked the jumpers--still NOTHING!!

Another call to tech support, & I actually spoke to the same tech again. He asked a lot of additional questions this time, & I was able to provide the answers that he desired, & he pointed me in a whole new direction--This time including the external potentiometer. The manual has a very clear diagram that even I could follow. He apologized for not sending me to that section initially. I went through the programming again, hooked up the jumpers, & now I have the motor running both forward & reverse, and with variable speed in each direction. One more hurdle cleared. I even took notes of how it is wired for when I get it installed on the lathe.

Now, I want to check the FWD/REV switch on the actual lathe. MKSJ told me that the contactors might be too corroded to function with the low voltage supplied by the VFD. I got lucky--Both directions work great.

My next big hurdle is all the safety switches. Tracking down the foot brake was easy. The case door, also easy. The EStop, not so easy. There are lots of wires in that panel. So, after a bit of detective work, I finally have all the switches figured out. They are all normally closed. So, I am guessing that if I connect them all in series and in series with the common wire to the FWD/REV switch on the apron, that all should be happy. I am just a bit hesitant to do it right now. Kind of basking in a small success--afterglow.

So, that's it for now from Delaware.

Jerry
 
Hi Jerry,

Most likely the VFD was programmed for external controls and the speed pot, if not connected it won't operate. The safety switches are all NC, so just connect them serially, usually before the stop switch. You can use an ohm meter to trace each one or follow the cabling back to the control box. Nice that you are making headway, took me quite a few tries the first time I wired up a VFD, and then there was the programing. But you are getting there. The KB should work fine with this size motor, it is not a big lathe, nor heavy duty. Some of the more industrial VFDs can take a much higher overload for short periods and can provide a bit better motor control, but you should get the benefits of the 3 phase and a smoother motor.
 
IT LIVES !!!!!

This afternoon, late, I removed the old motor, & all of the required stuff needed to hook up the VFD & new motor. Quite the job. I had to shorten the link belt by one link in order to get the new motor to clear the drip pan. No Biggee! Got everything lined up nicely & fired it up. Ran the first time. Now, you must envision this in your mind--cuz I'm not going take a picture of this mess. I have the motor mounted, temp wires everywhere, & the VFD lying on a work table nearby. I was clever enough to ground it all together.

OK, I can't wait. I set the VFD for 60 Hz & let it run a while at 840RPM. I'm on the high speed range for the belt. Still almost the same amount of total vibration as before--a tiny bit less, but not much. 840RPM is as close as I can get to the old motor settings without redoing the belt, etc. Close enough.
Same insert, same feed rate, same piece of aluminum--Some very, very slight hammering still visible--I would estimate the intensity to be less than half as much as before. When looking at it, it is noticeably better.

So, after I get everything back together and get permanent wiring installed, I can then start playing with speeds, feeds, & RPM settings to locate the sweet spot.
Overall, at this point I feel that I made a positive step forward.

I wish to thank each of the members of this forum for all the ideas & encouragement to undertake this project.

Jerry in Delaware.
 
Now it is time to get some vibration mounts.

:D

There is always one more job to do...
 
Moving Forward With the Project!!

Yesterday, & today, I worked at fabricating and installing a bracket to hold the VFD for the 1236. This VFD is huge!. So, in the following pics, you can see what I created.

The first pic is of the bracket to hold the VFD to the lathe. It is constructed from 1.5 inch square aluminum tubing--nice sharp corners--not rounded--3/16 thick. A bit overkill, but all that was available in the salvage yard that I frequent. The reason for the offset will be clearer later. I used my TIG to assemble it. My aluminum welding still leaves a lot to be desired. It still needs to be cut to length.

Bracket.jpg


This is a front view--I was back & forth several times about whether left side or right side was best--Right side finally won. The black cable coming through the splash shield is for the light power. I have a 12-volt wall wart that plugs into a receptacle on the back of the splash shield. I still do not have the left side of the lathe back together, yet. It all functions properly except for one important item--More on that a bit later.

VFD1.jpg


This is a side view of the whole assembly. There is a piece of the aluminum tubing inserted and bolted into the steel base that I built soon after acquiring the lathe. The upper support is bolted on 2 sides to the cabinet with large thick washers to help with possible "oil caning". It seems pretty rigid after a bit of test running--no actual machining yet. In the next Pic, you can see the offset to go around the splash shield. The bracket is not connected to the aluminum channel on the rear of the splash shield yet, but if needed for vibration reduction, I will do it later.

VFD on Bracket.jpg


OK, I mentioned one important item that does not function--or function properly. I need some help with this one. I have eliminated about 95% of the factory electrical stuff from the cabinet. Actually, I disconnected it, it is still physically in there--another day's project. I used mostly existing wiring for this install plus a 9 conductor cable from the VFD to the electrical box on back of the head stock. I wired all of the safety switches (except for the chuck guard) in series with the common power line that feeds both forward & reverse for the main motor. They all work as normal except for the foot brake switch. It works, but as soon as I remove my foot from the brake, it starts up again--NOT GOOD!! Any ideas how to cure this issue? When formulating an answer, you need to realize that there is no power other than VFD control power (low voltage) in the electrical box--NONE!!!!!

As always, Thank You All for your inspiration & support.
Jerry in Delaware
 
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Jerry, we would need to know how you wired up the VFD. If the brake switch restarts the system when reset, the same would occur with all the other safety interlocks and E-Stop. If it is only the brake switch it might be that the wiring is wrong, or it has a dual switch (3 wires), one NC and the other NO that might be wired into the system incorrectly. If you are not using any reset/power relays, then it will restart when the fault is correctly. I can look at the VFD settings and see if there is a programmable function that requires the VFD to be reset, but the spindle will engage immediately once the fault is corrected. You most use some form of power relay that requires a reset. I designed a system for a Grizzly lathe awhile ago and several people have used this schematic on their machines.
Regards,
Mark
 
That is correct, Mark. They will all restart--However, only the brake is important. Example--you cannot remove & then replace the gear end cover accidentally, or the E-Stop, either--no problems with those. I took the chuck guard switch out entirely. As you guessed, I wired the 3 switches in series with the common wire for the fwd/rev switch. I never thought to see if there is a stop function that would require other action for restart that could be used for the brake. I'll go through the manual again. I also need to determine if I can set up one of the sections for a jog switch.

I suppose that I could (with a lot of coaching) configure one of the relays for the brake switch. I am really not too thrilled about running another circuit into the lathe for that one switch, though.

Thanks,
Jerry in Delaware
 
Hey Jerry,
How is the VFD input terminals wired to the lathe, if directly connected to the spindle switch, then what you will have this restart issue and a risk. It is possible to wire in a latching relay, that when it trips requires the reset button to be pressed. If I recall this is how the standard G$003G is setup. I did a post elsewhere that use the contactors as relays for the VFD For/Rev, just removing the high voltage to the contactors. It should work exactly like the stock machine.
Mark
 
E-STOP switches are normally PUSH TO STOP & must be PULLED to permit restart
fixit
 
You are correct, Fixit. What I meant by my statements in post #67 was that I could not inadvertently or accidentally restart the lathe via the E-Stop or Cover (it requires some actual attempt to restart it). However, with the Brake, if I remove my foot, it starts right back up.

Gonna require some more thinking.

Jerry
in Delaware
 
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